Aphids

Aphids

Photo © Bulleen Art & Garden

We are planning to produce an aphid factsheet in the near future.. but in the meantime we thought you would find this interesting!

If you see these shiny puffy brown mummified aphids on your roses – leave them there – each of these aphids has been parasitised by a tiny black wasp and now has a single wasp growing inside it. Each wasp can parasitise 200 aphids. There are some amazing youtube videos – if you have a strong stomach….A little bit of patience and between the ladybirds, lacewings, hoverflies and parasitic wasps – all naturally around – we have our aphids under control and we have done NOTHING – just waited until a natural balance occurred (and bit off a few fingernails during the wait).

Beneficial Bugs

Beneficial Bugs

Most people know that one of the benefits of companion planting is to attract bees which help pollinate fruiting plants. However, an equally vital benefit is attracting insects which will prey on and control pest insects such as aphids. Giving these beneficial insects an environment in which to thrive, helps ensure a healthy balance in your garden and can dramatically reduce the need for sprays to control problem pests.
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Beneficial Insects and Mites – the BAAG experience

Beneficial Insects and Mites – the BAAG experience

Photo © Bulleen Art & Garden

To combat the appalling white fly invasion that was tormenting Melbourne gardeners in summer 2013 we introduced a parasitic wasp and a mite. They are susceptible to certain sprays – so we eliminated those pesticides to give them every chance to do their work. We saw a definite improvement in white fly control.
We used Montdorensis mites from and Encarsia formosa (parasitic wasp)

In 2015 we engaged the services of IPM Technologies and jumped feet first into managing our pests in a sensible and intelligently planned manner. This was a bit nerve wracking as it meant a lot more monitoring of pests and NOT reaching for the spray pack. Angelica from IPM Technologies regularly inspects the nursery and is the source of amazing photos of what is going on around the nursery. At this point we have not sprayed the roses at all (unheard of!) and spray once for Pear and Cherry slug. We introduced a predatory mite (Persimilis) into our poly tunnel which rapidly cleared up a burgeoning spider mite infestation before it became a problem. Apart from that, it has been a matter of watching and waiting and allowing the natural predators which were visibly there, to build up in numbers and control the aphids on the roses and hellebores, and the white fly on the shrubs and trees.

In 2019 Jen and Claire went to an industry training morning on IPM and came back fired up to increase the focus on our natural predators. As a result we have more insectory pots around the nursery planted with native species. These act as breeding grounds and food sources year round for our beneficial native insects.

Beneficial Nematodes for Natural Pest Control

Beneficial Nematodes for Natural Pest Control

Photo © Bulleen Art & Garden

Nematodes are tiny microscopic non-segmented round worms that are barely visible to the naked eye and which occur naturally in the soil. Some species of nematodes are pests which damage plant roots, while others are beneficial predators of pest insects such as lawn beetle grubs and fungus gnats for example. The beneficial nematodes are also called entomopathogenic nematodes (EN for short) which basically means that they’re insect-killing nematodes.

Since beneficial nematodes are natural part of the soil ecosystem, they’re a safe biological pest control to use around humans and pets, and they won’t harm non-target species such as bees and other beneficial insects. There is no issue with water runoff causing groundwater contamination or harming aquatic organisms either. Being non-toxic, there is no withholding period for edible plants after application, nor any exposure risk from touching treated lawns. Application is a straightforward process, beneficial nematodes can be applied to the soil using a low pressure sprayer or a watering can.

After they are released into the soil, juvenile nematodes track down their preferred pest insects through changes in carbon dioxide levels and temperature, or via the pest’s excrement trail. Once beneficial nematodes locate a pest insect, they enter into its body through its mouths or breathing pores. The nematodes don’t do the killing directly though, they carry a symbiotic bacterium which they release into the pest insect’s bloodstream, where it multiplies and kills the pest insect in around 2 days or less. The symbiotic bacteria also break down the dead insect tissues into food for the nematodes, and the nematodes feed and breed and multiply inside the decomposing insect. Once the food source is consumed, the new active juvenile nematodes will venture out to seek new prey, repeating the cycle.

There are various beneficial nematodes and they each target specific pests, so it’s important to select the right type. In the examples below we’ll look at two different ones.

Heterorhabditis zealandica – is used for scarab beetle control (including lawn beetle grubs) and weevil control. This EN utilizes an active search and destroy strategy to locate pests, and once they kill a pest, reproduce every 10-14 days, releasing up to 100,000 new nematodes from the dead beetle larvae.

According to Ecogrow, a vendor of EN pest control solutions, this EN will specifically control the following scarab beetles – Argentine Scarab African Black Beetle, Argentine Stem Weevil, Red-headed Cockchafer, Black-headed Cockchafer and the following weevils – Black Vine weevil (in soil temps over 15C only), Bill Bug.

Steinernema feltiae – is used for fungus gnat control in indoor plants, nurseries, mushroom growing and hydroponic systems. This EN utilizes an ambush strategy, waiting for the fungus gnat larvae to come close before attacking, and once they kill a pest, reproduce every 10-14 days, releasing up to 100 new nematodes from the dead gnat larvae.

As the beneficial nematode populations increase, they will wipe out most of the target pest insect. A level of around 90% control or more can be expected for scarab beetles, and with fungus gnats, if the population is well established, the number of adults will be noticeably reduced after 2-3 weeks.

In summary, biological controls such as beneficial nematodes are a safe alternative to synthetic chemical pesticides as they are non-toxic, do not affect non-target species, have no negative environmental impact, and are ideal for incorporating into a multi-tiered integrated pest management (IPM) strategy.

References:
http://ecogrow.com.au/pdfs/ECO%20Brochure%2002.pdf
http://ecogrow.com.au/pdfs/ECO%20Brochure%2002.pdf
https://pss.uvm.edu/ppp/articles/nemat.html

Black Aphid

Black Aphid

Photo © Bulleen Art & Garden

These can explode in numbers seemingly overnight and yesterday’s beautiful healthy foliage can turn into today’s twisted and curled up mess as you can see from the pictures here of our poor esplaiered cherry in Edible Alley (on the left as you enter the driveway). The difficulty with black aphid in this situation is that most sprays rely on getting the spray onto the aphid, and that is almost impossible when the leaves are curled up and the aphids are busy sucking away on the inside. Your best friends are ladybirds, lacewings and parasitic wasps. These will find the aphids within their curled leaves and they are excellent predators. A good supplier of natural predators is http://www.biologicalservices.com.au/.

If you can’t wait for the natural predator numbers to build up and just have to spray, using any of the contact insecticide sprays (pyrethrums, white oils etc) means you must get the spray onto the insect, so you will need to spray the undersurface of the leaves. Not an easy job when the leaves are curled up and this means you will unavoidably kill some of the natural predators.

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Blackspot and Powdery Mildew on Roses

Blackspot and Powdery Mildew on Roses

Photo © Bulleen Art & Garden

Blackspot on Roses

I grew up in South Australia where the hot dry summers were perfect for rose growing. Now I live in Melbourne and have had to become a lot more proactive in preventing and treating both blackspot and powdery mildew, as the wetter conditions leave the bushes a lot more vulnerable to attack. In a bad season, even the more disease resistant varieties can be affected. Not that this deters Melbournians from rose growing, this is after all the garden state (or was, and should be again) and people here clearly love their roses.
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Citrus Gall Wasp

Citrus Gall Wasp

(Photograph by Bulleen Art & Garden)

Citrus gall wasps (Bruchophagus fellis) are small (3mm) shiny black wasps native to northern Australia. There they have natural predators (two parasites) which keep the number of gall wasps under control. As the wasps have gradually moved south (thought to be via the movement of infected citrus trees), they have appeared in many areas without their natural predators, and consequently have exploded in numbers and caused considerable damage.
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Citrus Leafminer

Phyllocnistis citrella

This is a small nocturnal moth which lays its eggs on the underside of soft fresh leaves of citrus. The eggs hatch and the larvae rapidly burrow under the surface of the leaf, and it is these larvae that cause all the damage. The larvae feed on the epidermal cells of the leaf, creating the typical silvery snake-like ‘mined’ damage to the leaf.

Controlling Citrus-leafminer

Pheromone Traps
Finally something that works! One of our wholesalers in Victoria used these last year with great success. Called the eco-CLM Trap, it is a sticky trap combined with a very strong pheromone lure which attracts the male citrus leafminer. The result is fewer females able to lay eggs and much greater protection for your trees. The lure remains effective for around 2-3 months, and you need 1 for a small tree, 2 for a large tree. As soon as the weather warms up, the leaf miners become active, so install sometime in spring – temperature depending. Keep an eye out after 12 weeks and if damage is occurring – you may need to install another one. The pheromone is specific to the male Citrus Leafminer, so does not attract any beneficial insects that may be around.

Chemical control

While very difficult to control with insecticides because they are protected by their leaf ‘mines’, they can be managed by both cultural means and predatory insects. If choosing to spray, the best spray to use for the home gardener is white oil. The moths avoid leaf surfaces sprayed with oil. Spray every 5-7 days in warm weather and spray both upper and lower sides of new growth (don’t wait for leaf to fully open, start spraying when still tiny). Spray to the point of run off: i.e. have a fine mist over the leaves, but if the spray starts dripping off the leaves you have sprayed too much and the effort is wasted. Because this is an oil water mix, continually shake or agitate the mixture to prevent it from separating. Do not spray when the soil is dry, as trees should not be suffering moisture stress when you spray, and avoid spraying when over 32ºC.

Spinosad (marketed as Success) is reputed to be effective against leaf-miners, particularly Tomato leaf-miner. Whether or not it is effective against Citrus Leafminer is not known yet.

Natural Enemies

Brown and Green Lacewings predate on Citrus Leafminer. Green Lacewings are available as a biological control. They are highly susceptible to pesticides, so do not release them for 4 weeks after residual pesticide use.

Cultural control

Citrus Leafminer is most active over summer and autumn and is restricted to soft new growth, so you need to adjust pruning and feeding regimes to get the soft new growth when the Citrus Leafminer is not active. Keep watering and fertilizing to the minimum required for the health of the tree for the rest of the year. Prune leaf flushes at other times of the year.

Codling Moth and Oriental Fruit Moth

The chemicals commonly used to control codling moth also kill beneficial insect species, which contribute to biological control of other pests. Consequently increased chemical sprays are required for control of other pests. The most successful way to avoid this problem is to use Integrated Pest Management (IPM). Using a combination of pheromones and sticky traps, good orchard hygiene and traps will help you avoid the revolting coddling moth.

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Cottony Cushion Scale

Cottony Cushion Scale


This is great shot of Cottony Cushion Scale on a citrus leaf which was brought into the nursery today for identification. It shows them sitting along a citrus leaf, along the middle rib. This is where you will normally see them congregating.

Unfortunately spraying is not really an option, as any spray that will kill the scale is not selective and you will end up knocking out your garden’s ‘good guy’ predators. This could also compound the problem by making future infestations worse. Your best friends in this situation are two of your garden’s natural predators… ladybirds and green lacewing. You can boost your garden’s natural pest-fighting ability by releasing some of these natural predators yourself.
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Elm Leaf Beetle

Elm Leaf Beetles are present on most Elms throughout Melbourne. There are many Elm trees in Melbourne, both
planted as street trees, in public parks and reserves, and in private gardens. Although the Elm Leaf Beetle is
present in significant populations, Dutch Elm Disease, for which the beetle is the carrier, is not present in Australia. This disease has devastated many Elm Tree populations around the world.

Damage Caused

The damage caused to trees is different at different times of the year, depending on the stage in the life cycle of the beetle. In spring new leaves will have many small holes chewed through the leaf, called shot hole damage. This is caused by the adult beetle, a pea – sized, oval shaped beetle with yellow and black stripes.

The adult beetles then lay their eggs on the undersides of the leaves. These hatch out after 7 to 10 days. The
larvae hatch out and feed on the green parts of the leaf, completely skeletonising the leaves. In late December the larvae move down the trunk to pupate in the soil and in lower crevices in the bark. After one to two weeks the adult beetles emerge and travel back up the trunk to feed on the foliage. As the weather cools down the beetles seek shelter for the winter months. The beetles will over winter in houses, sheds, wood piles, compost bins, even in vehicles.

In Melbourne, one to two of these cycles occur each year, depending on the seasonal weather. The damage to the trees depends on the health and age of the tree. Older trees that suffer other environmental stresses, such as drought or compaction of the root zone, will be weakened and may decline at a faster rate. Young trees that are otherwise healthy and vigorous will be more able to cope with the beetle infestations each year. Watering trees in drought periods and avoiding damage to the roots will result in healthier trees, more able to cope with the yearly beetle attack.

What can be done?

The aim is not to eradicate Elm Leaf Beetle, but to reduce the numbers so that the damage is minimised. There are several methods that may be used to reduce the numbers of beetles and larvae feeding on your Elm trees.

Trunk banding: Two bands, approximately 20cm apart, of clear film with a band of Tac Gel applied around the trunk. This should be applied early in January as the idea is to trap and kill larvae moving down the trunk to pupate. On smooth barked Elms, sticky packaging tape may be wound in a 20cm wide band around the trunk, with the sticky side facing out. This is a physical trap for larvae moving down the trunk and as such should be replaced when it loses its stick or gets clogged with larvae.

Foliar Sprays: This method is only useful for immediate control of the beetles and larvae feeding on the foliage. This method is difficult for the home gardener to apply due to the size and height of the canopy. For most established trees, this method is both expensive and short term and is the most environmentally damaging. This method is not recommended as an effective and safe control method.

Trunk injection: This method can only be administered by an arborist, as both the technique used, and the equipment used is specific. Most arborists would not recommend this method, as there are more effective and
cheaper ways to control Elm Leaf Beetle.

Need More Information?
Friends of The Elms at Burnley: e-mail foteinc@hotmail.com

There are also several arboriculture services that can help:
Arbor Spray: 0419 546 376
Tree Logic: (03) 9822 2181
Arbor Co: (03) 9804 3366
City Wide Tree Care: 1300 136 234

Encouraging native beneficial insects

Encouraging native beneficial insects

Photo © Bulleen Art & Garden

A healthy garden is full of life, from deep in the soil to the tree tops there should be fungi, bacteria, spiders, insects, worms, and innumerable other living creatures. These all cohabit in a generally harmonious way. Sometimes, however, a problem arises and the balance is temporarily upset. Reaching for an insecticide spray when aphids appear on your tender rose buds will often make the problem worse in the long run. Most insecticides are not prejudiced, they will kill everything, both the aphids and their natural predators.
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Freckle, Black Spot or Scab on Apricots, Peaches, Nectarines and Plums

Freckle, Black Spot or Scab on Apricots, Peaches, Nectarines and Plums

Photo © Bulleen Art & Garden

This is a fungal issue affecting stone fruit. It is seen as small dark spots on immature fruit, becoming round brown freckles, sometimes scabby, on mature fruit. It is often just cosmetic and the fruit is perfectly fine to eat, however it become so dense that the fruit is rotten or shrivels and falls off. It is mostly apparent towards the end of the season, as the fruits swell and ripen. At this stage it is too late to do anything about your current crop. However, there is plenty to do to avoid future problems.
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Fungal Gnats in your pot plants

Fungal Gnats in your pot plants

Photo by John Tann. Sourced from Wikipedia

It is the larval stage of these small flying insects that create the most havoc, but their numbers can build up to such a level that the flying gnat itself creates an unpleasant nuisance in the house. Small dark bodies with long legs and a single pair of wings, these small flying insects commonly live around a week before dying en masse, usually on your sunny windowsill just before your mother in law comes to visit.
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Gall Wasp Preventative Treatment – ‘Overhaul’

Photo by NSW Department of Primary Industries

Finally we have a new preventative for the infuriating gall wasp that has been decimating our citrus, lemon trees in particular, across Victoria.

‘Overhaul’ is an organically* rated kaolin clay (used in papermaking and ceramics) and has been used in broad-acre agriculture to reduce heat stress and sunburn in tree and horticultural crops (e.g. tomatoes) for 18 years; in that time an unexpected secondary benefit has become apparent: the fine coating of clay resulted in less insect damage to crops. It is hypothesised that the clay works in a variety of way depending on the insect: repelling, reducing egg laying, impeding grasping, restricting movement, altering behaviour, inducing paralysis and mortality, and camouflaging the plant. Whichever way it works, trials by the NSW Dept. of Agriculture in the Riverland and Sunraysia have found it significantly reduces the incidence of galls (from Citrus Gall Wasp) in their citrus trees. Both number and size of galls are reduced (70-90%).

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Garden Pest Control

Photo © Charles J Sharp

Effective and sustainable pest control for the garden.

It is only within my lifetime that consumer standards have changed so dramatically to the point where there is currently an expectation that all fruit and vegetables should be perfectly shaped, unblemished and of a specified colour. In order to achieve this level of ‘perfection’ commercial producers are forced into using a significant amount of chemicals. Luckily this is not the case for the home gardener, who can retain a sense of realism and common sense about the appearance of fruit and vegetables. Our gardens are all highly complex and interactive ecosystems, the actions we take have both short and long term effects. Listed below are a wide variety of pest management methods which you can use in your garden. All the recommended methods have a relatively low environmental impact but are effective.

Integrated pest management.

Gardeners looking for an environmentally responsible approach to pest management are adopting principles of Integrated Pest Management (IPM). This enables them to use multiple compatible tactics to control pests. The environmental and economic effects of widespread synthetic chemical use have led to the development of IPM where the problems of insect resistance, toxicity to humans and beneficial insects, and harm to the environment are addressed. Techniques including biological control, trapping and monitoring, highly specific microbial pesticides and selective and timed spraying are all part of IPM.

Beneficial insects and mites

A beneficial insect or mite acts as a predator, parasitoid or competitor of pest insects i.e. they are natural enemies of the pest species. Unlike insecticides which generally result in an immediate knockdown effect, the release and use of beneficial insects and mites takes longer to have an effect. Also the effect is to reduce the damage, often to a completely acceptable level but not completely eliminate damage (as needed in some ornamental flower crop production).

Predators

Usually as big or bigger than their prey, predators are predaceous as larvae and or as adults. They may be generalists, feeding on a wide range of prey, or specialists, selectively feeding on a narrow range of prey.

Ladybeetles (also called Ladybugs and Ladybirds) (pictured above) are beneficial as both larvae and adults, feeding primarily on aphids, but will also feed on mites, scale, thrips, small insects and insect eggs. Voracious feeders, they are effective predators and their numbers will build up with the food supply if broad spectrum pesticide use is limited.

Photo © Guido Bohne

The Mealybug Destroyer (Cryptolaemus montrouzieri), (pictured above) is a native Australian lady bird, black with an orange ‘head’ (pronutum), the larvae look very similar to its mealy bug hosts being covered with shaggy white waxy material. Another voracious feeder, where both larvae and adults are predaceous, each ladybeetle may eat up to 250 mealybugs during its development. The photograph above was taken by Flickr user Guido Bohne

The Green Lacewings
With delicate pale green bodies and large transparent wings, the adult lacewings are only rarely predacious; it is their larvae which are the generalist predators. Sometimes referred to as ‘aphid lions’ they are voracious feeders of aphids, but will also eat other soft bodied insects, mites and insect eggs.

Typhlodromips montdorensis: This Australian predatory mite feeds on larval stages of thrips, whitefly and other small insects.

Parasitoids: These are parasite like insects, often the same size as their hosts and always killing their host (unlike true parasites which are often smaller and rarely kill their host). The parasitoid will develop on or within a single host during their development. Most parasitoids are highly host specific, and the vast majority are small to minute wasps. Example: Encarsia formosa a tiny wasp which parasitises the larval stage of whitefly.

All the following Cottony Cushion Scale, Black Aphid, Mealybugs, Citrus Leafminer have commercially available natural predators.

Suppliers of Beneficial insects and Mites Biological Services in South Australia Bugs for Bugs in Queensland

Lures, physical barriers, exclusion and traps

These range from netting trees to simple yellow sticky traps to the pheromone traps requiring some knowledge of the correct timing and correct lures for targeted pests.

Sticky traps and Glues

Horticultural glues and sticky bands or tapes are used to prevent insects crawling up tree trunks and into the tree canopy to feed on the leaves and or fruit. Good for codling moth, tent caterpillars, procession caterpillars and ants. Ants protect aphids, scale and mealy bugs, so reducing ant numbers aids in reducing these pest numbers. Yellow sticky traps are useful in greenhouses but also can be used for specific pests such as citrus gall wasp. Effective until trap is full of insects and no sticky surface is available. Non-discriminatory – will trap predators as well as pests.

Netting

A variety of nets are available which surround the plants to be protected and provide a physical barrier against the pest. Fine netting allows water and light to penetrate but prevents insects from entering and causing damage.

Advantages: No chemicals, no toxicity, can also aid in preventing hail damage and bird damage.
Disadvantages: If insects are already present, they will be included inside the barrier, and will need to be treated. See our cabbage white butterfly fact sheet.

Lures Pheromone lures are used at specific times to lure the pest to a trap, usually before breeding to interrupt the breeding cycle. See our codling and oriental moth fact sheet

Microbial Insecticides

Microbial insecticides are composed of microscopic living organisms (viruses, fungi, bacteria, protozoa, nematodes) or the metabolites produced by these organisms. They are formulated as conventional insecticidal dusts, sprays or granules.

Advantages: Essentially nontoxic and nonpathogenic to wildlife, humans, and other organisms not closely related to the target pest. The toxic action of microbial insecticides is often specific to a single group or species of insects. This means the natural predators and competitors of the target insect remain unaffected by the insecticide. Most microbial insecticides can be used in conjunction with synthetic chemical insecticides because in most cases the microbial product is not deactivated or damaged by residues of conventional insecticides. As the residues are considered harmless, can be used on crops close to harvesting. In some instances the microbe can become established in the pest population and provide ongoing control over the season and possibly subsequent seasons.

Disadvantages: They are specific to only a well defined range of target species, this means that only those pests are treated, other damaging pests are untreated, this is also true with other pesticides, but is more noticeable with microbial insecticides. Heat, desiccation (drying out), or exposure to ultraviolet radiation reduces the effectiveness of several types of microbial insecticides. This means correct application processes are more important with these insecticides. Special formulation and storage procedures are necessary for some microbial pesticides.

On the shelf: Bacillus thuringiensis (abbreviated as Bt): A bacterial pathogen occurring commonly in soils. Must be eaten by the target pest to be effective. Although the target insect may take a few days to die, it will stop eating rapidly after ingesting Bt treated foliage. Bt does not reproduce and infect subsequent generations of the target pest so must be re-applied as necessary. The most widely known and used Bt is Bacillus thuringiensis var. kurstaki, these are toxic only to larvae of butterflies and moths and have proved invaluable in controlling damage done to many crops, including the brassica crops (cabbage, cauliflower, kale, Brussels sprouts). Bt degrades rapidly with UV, and may need to be applied twice a week if the pest problem is severe. Can be found on the shelf as Dipel Spinosad is an insecticide derived from naturally occurring soil bacteria Saccharopolyspora spinosa. Spinosad is highly active by both direct contact and by ingestion to numerous pests. It will move into the leaf giving it residual activity and some resistance to sunlight and rain (although any spinosad remaining on leaf surface will be rapidly broken down by sunlight and rain). Spinosad affects some insects at multiple life stages and others only in the adult stage. Considered a natural product, spinosad is approved or use in organic farming by numerous nations. It has high efficacy, a broad insect pest spectrum, low mammalian toxicity and a good environmental profile. Various studies have concluded that spinosad offers a negligible risk to honeybees. Can be found on the shelf as Success Fruit Fly Control and as Tomato & Vegetable Dust (Yates).

Insecticidal soaps

Insecticidal soaps are selected and formulated for their insecticidal properties (contain the potassium or sodium salts of insecticidal fatty acids). Despite many years of use the exact manner of action of insecticidal soaps is unclear. Some physical disruption of the insect cuticle is known to occur, but other toxic activity is assumed. There is some evidence that the cell membranes are broken down and call metabolism disrupted.

Uses: Useful for controlling soft bodied pests such as aphids, thrips, scale (at the crawler stage only), whitefly, leaf hopper nymphs and mites. Effective only when wet spray comes into direct contact with the insect. Adult forms of beneficial predators are generally safe from the soap spray – but their immature forms may be susceptible.

Advantages: Rapidly broken down by enzymes and degrade rapidly in sunlight, moisture and air. This is considered advantageous as it is less persistent in the environment and non – target organisms are less likely to be at risk Rapid action – insect stop feeding almost instantly, even if death occurs days later. Often (but not always) low toxicity to mammals

Disadvantages: The rapid breakdown means more frequent applications may be needed and more precise timing of application Whilst mild, still has some degree of toxicity (like any soap) and care needs to be taken

On the shelf: Bug Guard (potassium salts of fatty acids) Multicrop Natrasoap (potassium salts of fatty acids) Yates

Botanical insecticides

Sometimes just referred to as ‘botanicals’ are naturally occurring insecticides derived from plants.

Background: In common use from the late 1800s until mid 1940s. The development of synthetic insecticides led to the wholesale abandonment of botanicals in commercial agriculture and horticulture. Since early 2000 the resistance of key pests to synthetic insecticides has led to the re-introduction of some botanicals into commercial use, and a general increase of interest in their use. Concern about environmental contamination and pesticide residues has also fostered renewed interest in botanicals. The increase of certified organic production has also led a resurgence in the use of botanicals and increased research and development of new botanicals.

Advantages: Rapidly broken down by detoxification enzymes and degrade rapidly in sunlight, moisture and air. This is considered advantageous as it is less persistent in the environment and non – target organisms are less likely to be at risk Rapid action – insect stop feeding almost instantly, even if death occurs days later. Often (but not always) low toxicity to mammals Some need to be ingested, hence only the chewing/sucking insects are affected and their natural predators remain unaffected. Almost never phytotoxic (Toxic to plants)

Disadvantages: The rapid breakdown means more frequent applications may be needed and more precise timing of application Whilst most botanicals pose fewer hazards than synthetic insecticides, some degree of toxicity exists and some botanicals (e.g. nicotine) are highly toxic, so care always needs to be taken. ‘Natural’ and ‘botanical’ does not necessarily equate to ‘safe’ or ‘non-toxic’.

Botanical insecticides for garden use include:

Pyrethrum and Pyrethrins Easily confused with pyrethroids which are synthetic compounds based on the chemical structure and physiological action of naturally occurring pyrethrins. The pyrethroids are often much more persistent in the environment and toxic to insects. Pyrethrum is the dried powdered flower head of the Pyrethrum Daisy (Chrysanthemum cinerariaefolium). The pyrethrins are the 6 related insecticidal compounds that are derived from this raw material. Their mode of action is disruption of the sodium and potassium ion exchange in insect nerve fibres and interruption of normal transmission of nerve impulses causing almost immediate paralysis (the knockdown effect). This effect is often very short lived and the insect commonly can recover. To prevent this pyrethrin insecticides generally contain a synergist PBO which prevents the insect from degrading the pyrethrin and recovering. PBO is low in toxicity, has no inherent insecticidal activity and is not persistent in the environment. Toxicity: Pyrethrins are low in mammalian toxicity – one notable exception is cats which are highly susceptible to poisoning by pyrethrins. Uses: Effective against a broad range of insect pests. They are contact poisons (spray must land on the insect) and have almost no residual activity, so repeated applications may be needed.

Rotenone An insecticidal compound found in the roots of several plants from the Fabaceae family and in the stems and leaves of several other species of plants including the roots of the Lonchocarpus nicou species in South America and the Derris elliptica species in Asia In insects rotenone acts at the cellular level, primarily on nerve and muscle cells, resulting in almost immediate cessation of eating, although death may take several hours or days. Toxicity: Extremely toxic to fish, used as a fish poison in water management programs. One of the more acutely toxic botanicals, care needs to be used when applying this compound. Uses: A broad spectrum contact and stomach poison, very effective against leaf feeding beetles and certain caterpillar pests. Has some residual effect and when applied as a dust, will remain active for approximately 6 days. On the shelf: Found in Derris Dust

Sabadilla First used in the 16th Century, the insecticidal dust is derived from the ripe seeds of Schoencaulon officianale, a tropical lily plant from Central and South America. The toxic alkaloids cause immediate paralysis of insects, in some cases immediate death, in others death may occur several days later. Toxicity: Highly toxic to honey bees. Low mammalian toxicity. Uses: A broad spectrum insecticide, effective against certain bugs from the Hemiptera family (e.g.Harlequin bugs, leaf hoppers, aphids). Rapidly degrades leaving little residual activity.

On the shelf: Natural Pyrethrum (pyrethrins, PBO) Sharp Shooter Beat a bug (garlic/chilli/pyrethrins/PBO) Richgro Derris Dust (Rotenone) Amgrow

Using oils as a pesticide.

Nerdy background stuff

Oils are distilled from petroleum, plants or animals. Those oils distilled from petroleum in horticultural use are highly refined paraffinic oils often referred to as ‘white oil’ or ‘horticultural oil’. Regardless of where the oil is sourced from, the mode of action is similar: Insecticidal oils kill insects on contact by disrupting gas exchange (respiration), cell membrane function or structure. They also kill them by altering their behaviour such as disrupting their feeding on oil covered surfaces or reducing egg laying. Their toxic action is more physical than chemical and is short-lived. Fungicidal oils smother fungal growth and reduce spore germination on treated surfaces. They are mostly fungistatic, stopping fungal growth rather than killing the pathogens. Some plant oils that contain sulfur compounds, such as neem oil, may possess additional fungicidal activity compared to petroleum oils. Stylet oils are highly refined oils and may control insect-vectored plant viruses in addition to insects, mites and fungal pathogens. These oils reduce the ability of aphids to acquire the virus from an infected plant and transmit it to healthy plants. Stylet oils may interfere with the virus’s ability to remain in aphid mouthparts (stylets).

Advantages of oils over synthetic broad-spectrum pesticides

  • Many pests can be controlled simultaneously.
  • They have less harmful effects on the natural predators of the pests
  • They do not stimulate other pest outbreaks.
  • Pests are not known to develop resistance to them.
  • The oil deposits are broken down within weeks to form simple, harmless molecules.
  • When using oils only minimum protective clothing needs to be worn.
  • They are suitable, depending on the emulsifiers and additives used to formulate products, for use in organic farming.
  • They are not toxic to humans or other animals.

Using oils

Phytotoxicity: This simply refers to the damage that may occur to the plant by the oil. As the quality of oils has improved, instances of phytotoxicity have reduced, none the less some oils can injure plants (leaf scorching and browning, defoliation, reduced flowering and stunted growth) and as a general rule do not use oils on stressed plants. Do not apply on hot days, very cold days or days of high humidity. All oil products have emulsifiers added to enable them to be mixed with water and used as a spray. When sprayed onto a leaf, the oil tend to stay on (or be absorbed by) the leaf, while the emulsifier and water runs off the leaf. Always use oils as indicated on the label. Spray immediately after mixing, and agitate the mix as you go along. Some oils are incompatible with other products, it is essential you check the label for this, for example do not apply an oil spray within 1 month of a sulphur spray.

On the shelf: Eco Oil (Botanical Oil) OCP Pest Oils (Petroleum oil) Yates

Neem oil

Background:

Neem or neem oil is extracted from the seeds of the Neem tree, Azadirachta indica, a native of India and has recorded use in India for many hundreds of years. In the mid 20 century serious academic research began on neem oil and its properties. As a result a number of Neem based commercial products have come on to the market. The oil is made from many components, with at least 3 compounds known to have insecticidal properties: azadirachtin, meliantriol and salannin.

Horticultural uses:The best understood and active component of neem oil is azadirachtin. The azadirachtin must be ingested by the insect eating the treated plant for it to work (remaining active on the plant for 1 to 2.5 days). It acts as both an insect feeding deterrent and as an insect growth regulator. Azadirachtin prevents the treated insect from moulting and transitioning to the next life stage, it subsequently dies, thus preventing it reaching maturity, mating and reproducing. Consequently Neem is most effective against sucking and chewing insects in their actively growing immature stages (e.g. caterpillars, mites, curl grubs, aphids, leaf miner, whitefly). Death may occur in 2 or more days, but damage to the plant stops immediately. A significant advantage of neem oil is that it does not harm beneficial insects such as lacewings and other predators in the garden, hence is excellent to use when using Integrated Pest Management (IPM) as a way of controlling problem insects. Further it does not appear to harm pollinating insects such as bees, and is safe around pets and people. Azadirachtin acts as an insect repellent when applied to a plant and it also has some systemic activity. It is known to repel and reduce the feeding of nematodes. Other components of neem oil kill insects by hindering their ability to feed. The exact mode of action of all the components of neem oil is yet to be fully understood.

Safety:Neem has extremely low mammalian toxicity and in most forms is non-irritating to mucus membranes and skin.

On the shelf: Eco-neem (Azadirachtin) OCP

Mineral based pesticides

Sulphur (syn sulfur) Sulphur probably is the oldest known pesticide in use. Sulphur is formulated as a dust, wettable powder, paste or liquid. Primary used to control powdery mildews, certain rusts, leaf blights and fruit rots, it can also assist in controlling Spider mites, psyllids and thrips. Most pesticidal sulphur is labelled for vegetables such as beans, potatoes, tomatoes, peas and fruit crops such as grapes, apples, pears, cherries, peaches, plums and prunes. Sulphur has the potential to cause plant injury in dry hot weather. It’s also incompatible with other pesticides. Never use sulphur on plants within 30 days of applying spray oils. Sulfur is non-toxic to mammals, but it may irritate eyes and skin.

Lime Sulphur Lime sulphur is made by boiling lime (calcium hydroxide) and sulphur together with a small amount of surfactant. The mixture is used as a dormant spray on fruit trees to control diseases such as blight anthracnose, powdery mildew, black spot and some insects including scales, thrips and eriophyid mites. Its drawbacks include its rotten-egg smell, its potential to burn exposed skin and eyes and to injure plants if applied when temperatures exceed 27degrees C.

On the shelf: Sulphur (Sulphur) David Grays powdered sulphur Tomato and Vegetable Dust (Sulphur, Copper, spinosad) Yates

Good Bug Seed Mix

Good Bug Seed Mix

Photo © Bulleen Art & Garden

An important strategy for organic gardeners is to enhance and maximise the natural biological controls already present in a garden ecosystem. Does your garden provide a nectar source for beneficial, pest-controlling insects? Planting particular flowers and herbs known as insectary plants has been proven to improve the natural balance and reduce pest outbreaks.

Good Bug Mix contains colourful re-seeding annual and perennial flowers including red clover, alyssum, cosmos, marigolds, Queen Anne’s Lace, buckwheat, lucerne, dill, caraway, coriander and phacelia (when available), gypsophila. It blooms much of the year, providing nectar, pollen and habitat for wild and introduced beneficial insects, such as predatory mites and tiny micro wasps, ladybirds, lacewings, hoverflies, tachnid flies and predatory beetles. These beneficial insects or ‘good bugs’ are generally small with correspondingly small mouthparts, so they are only able to feed on particular flowers with suitable attributes. By providing a plentiful food supply the ‘good bugs’ live longer and reproduce more. Good Bug Mix is available in our seed section all year round, and is best sown during spring and autumn.

Thanks to Green Harvest for the information and pics – greenharvest.com.au.

Gummosis (Bacterial Canker) in Apricots

Gummosis (Bacterial Canker) in Apricots

Photo © Bulleen Art & Garden

This disease has become almost endemic in apricot trees across Melbourne. It is now a disease that we need to prevent, live with, and manage. Gummosis is identified by the gum or sap that oozes from a wound in the bark of the tree. The wound can be from splitting during a rapid growth phase, physical damage from whipper snipper, mower or other accidental damage, or from boring type of insects.

When you first notice the oozing sap, look carefully to see if there is any frass or sawdust in the ooze. If there is, then you have a boring insect causing the damage. Insects tend to attack trees which are already stressed, so it helps to increase the vigour of your tree with a good watering and fertilising regime. Make sure it has good drainage and optimal pH.

Gummosis is a bacterial infection, so while spraying with a fungicide might make you feel proactive, but it is unlikely to solve your problem. The better approach is to start with good hygiene and clean up all fallen leaves and plant material on the ground. Trees are at their most susceptible as they are coming out of dormancy – do not prune over this time. You should always prune apricots in the warmer months (NOT in winter). This allows for a more rapid sealing of the pruning wound and reduces the opportunity for the bacteria to gain an access point to your tree. Only prune when the weather is dry. When pruning you should always disinfect your secateurs frequently during the process. A small spray bottle of methylated spirits will do the job. Make sure your secateurs are sharp to prevent any tearing and pulling.

Feed your apricot with a fertiliser high in potassium and phosphorus to encourage flowering and healthy growth. A good N:P:K ratio is 6:3:9. Fertilise in late winter, again in mid spring and lastly in mid summer if needed. Avoid feeding in late summer and autumn, as you do not want a lot of soft sappy new growth going into winter. This takes longer to harden off and is more susceptible to bacterial infection.

Promote good vigour in your tree by keeping the pH slightly alkaline. In this area (Manningham), the natural pH is neutral to slightly acidic, so an application of lime is a good idea. Fertilise regularly and water well, but ensure your tree is never sitting in water or is overly damp. Good drainage is important for apricots.

Apricots are prolific early bearers and a heavy load of fruit on young sappy branches can lead to splitting, especially in the branch crutches. You can thin the fruit, cut the branches shorter, prop up the branches or tie up the branches with broad soft ties. Splitting allows the bacteria an entry point – and is to be avoided whenever possible.

Gummosis will eventually shorten the life of your apricot tree, but in the meantime, you can live with it and still have a very productive tree for many years.

Insect Hotels

Insect Hotels

Photo © Bulleen Art & Garden

Beneficial insects are insects you want in your garden, either for pollinating or for predating on pest insects. To encourage them into your garden you can provide them with nesting and hibernating sites, if a garden strewn with dead branches isn’t your thing, you may prefer to add in an insect hotel. These are particularly useful for solitary bees and solitary wasps.
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Land Cress as a Natural Pest Control

Land Cress as a Natural Pest Control

Land Cress (Barbarea vulgaris and Barbarea verna) releases chemicals which attract the Diamondback Moth (right) and the Large Cabbage Moth (left) – both small brown moths which are common pests in the vegie garden. These moths lay their eggs in the Land Cress, subsequently the emerging caterpillars feed on the Land Cress, are poisoned by the saponins in the leaves and die. So if you hear Land Cress referred to as a ‘Dead End Trap Crop’ – that is why.

Also worth noting is Land Cress – Barbera verna – is a nice spicy addition to salads.
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Mealybugs

Mealybugs

Mealybugs

These little insects are 3-7mm long and covered in a white ‘mealy’ wax. Adults are slow moving and feed by sucking sap from the plant tissues. Females lay their eggs in a cocoon of waxy filaments, as many as 200 eggs can be laid in a lifetime and consequently their numbers can rapidly expand; particularly in temperatures around 25C (high humidity is also favourable for population growth – often seen in greenhouses).

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Mosquito Repellent Plants

Mosquito Repellent Plants

Photo © Bulleen Art & Garden

Perfection is sitting outside with the warm sun on my face, the company of friends and family, and food on the table. To keep this image of perfection firmly in place, I need to exclude the uninvited guest – the mosquito.

I can slather on insecticide, have bottles ready for other people to use, or I can plan ahead, and create a mosquito free garden. They have lots of options, they don’t have to be in my garden, so I plan on making it as unattractive to them as I can, sort of a cultural desert for mozzies, no where to hang out, unattractive smells, nothing enticing.
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Myrtle Rust

Myrtle Rust is a plant fungal disease that was first diagnosed in NSW in Myrtaceae family plants in April 2010

Myrtle Rust is now in Victoria. To a greater or lesser extent (depending on flora and climate conditions) this will change our landscape. It appears that we have no choice but to adapt and learn to live with this fungus. It attacks plants from the Myrtaceae family (list below), some are affected more badly than others (Lophomyrtus, Syzygium and Agonis). Badly affected species are referred to as host plants. We recommend that susceptible host plants be removed in highly infected areas, as re-infection after fungicide application is highly likely. Replace with non susceptible plants, preferably not from the Myrtaceae family.

Rust spores travel very long distances on the wind and may infect stands of susceptible plants many kilometres from the original infestation. Rust spores are also gathered and spread by bees.

Fungicides are effective in the control of Myrtle Rust. Rotation of fungicides between products containing different active ingredients is recommended to ensure fungicide applications remain effective.

Fungicides available to the home gardener for myrtle rust control on non produce plants (i.e. do not use for food plants) are:

Copper oxychloride. Use at 30g per 10L water and leave a minimum of 7-14 days before spraying again.
Mancozeb. Use at a rate of 23g/10L water and leave for a minimum of 7 days before spraying again.
Triforine. Use at a rate of 13ml/10L water and leave for a minimum of 7 days before spraying again.

Do not use any of these sprays more than twice in a row before switching to an alternative spray. Spray to the point of run off. This means just that – stop spraying before the spray runs of the plant – you want a fine mist all over the surfaces of the plant, you don’t want it to run off.

Read the instructions on the label of the product and follow these instructions.

Genus List of Myrtaceae      
Acca Cheyniana Lophomyrtus Pleurocalyptus
Accara Choricarpia Lophostemon Plinia
Actinodium Chytraculia Luma Pseudanamomis
Agonis Cloezia Lysicarpus Psidium
Algrizea Conothamnus Malleostemon Psiloxylon
Allosyncarpia Corymbia Marlierea Purpureostemon
Aluta Corynanthera Melaleuca Regelia
Amomyrtella Curitiba Meteoromyrtus Rhodamnia
Amomyrtus Cyathostemon Metrosideros Rhodomyrtus
Angasomyrtus Darwinia Micromyrtus Rinzia
Angophora Decaspermum Mitranthes Ristantia
Archirhodomyrtus Eremaea Mitrantia Sannantha
Arillastrum Eucalyptopsis Mosiera Schizocalomyrtus
Astartea Eucalyptus Myrceugenia Scholtzia
Asteromyrtus Eugenia Myrcia Seorsus
Astus Euryomyrtus Myrcianthes Siphoneugena
Austromyrtus Gomidesia Myrciaria Sphaerantia
Babingtonia Gossia Myrrhinium Stenostegia
Backhousia Harmogia Myrtastrum Stereocaryum
Baeckea Heteropyxis Myrtella Stockwellia
Balaustion Hexachlamys Myrteola Syncarpia
Barongia Homalocalyx Myrtus Syzygium
Basisperma Homalospermum Neofabricia Taxandria
Beaufortia Homoranthus Neomitranthes Tepualia
Blepharocalyx Hottea Neomyrtus Thaleropia
Britoa Hypocalymma Ochrosperma Thryptomene
Callistemon Kania Octamyrtus Triplarina
Calothamnus Kardomia Osbornia Tristania
Calycolpus Kjellbergiodendron Oxymyrrhine Tristaniopsis
Calycorectes Kunzea Pericalymma Ugni
Calyptranthes Lamarchea Petraeomyrtus Uromyrtus
Calyptrogenia Legrandia Phymatocarpus Verticordia
Calytrix Lenwebbia Pileanthus Welchiodendron
Campomanesia Leptospermum Pilidiostigma Whiteodendron
Chamelaucium Lindsayomyrtus Piliocalyx Xanthomyrtus
Chamguava Lithomyrtus Pimenta Xanthostemon

Peach Leaf Curl

Peach Leaf Curl

Photo © Bulleen Art & Garden

Every September we get customers bringing in thickened bubbly curled and distorted leaves from their peaches and nectarines, by then it is too late to treat and all we can do is offer a rueful smile and tell people what to do for next year. This is Peach Leaf Curl, a very unsightly and damaging problem caused by the fungus Taphrina deformans. If left untreated, it can cause dieback of new shoots, early fruit drop, reduction of vigour, and eventually death of the tree. The cool wet spring conditions in Victoria are ideal for this particular fungus, so you need to be proactive in controlling this disease.
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Phosphorus and Australian Native plants

Most Australians have heard at one time or another, that our soils are almost universally phosphorus deficient. In a truly fascinating manner, Australian plants have evolved various ways of coping with low phosphorus levels: some develop symbiotic relationships with fungi, others have developed root structures which increase ability to find and absorb phosphorus. Somehow, this information, has segued into the incorrect idea that phosphorus is toxic to all Australian natives, and applying a phosphate fertiliser will kill native plants.

The reality is that while a few natives cannot tolerate phosphorus, many can benefit from the application of a complete fertiliser (one containing phosphorus). If your native is looking healthy it probably won’t benefit from an application of fertiliser, but if it is looking hungry, then it may respond well to an application of a balanced fertiliser. Natives generally prefer the slow release of fertiliser rather than a sudden large dose which may cause toxic shock.

It is important to note that the use of phosphorus is linked to the level of iron. If iron is deficient, then plants cannot metabolise the available phosphorus. Hence a balanced fertiliser is better, one that has Nitrogen, Phosphorus, Potassium and trace elements.

Equally important is being aware of those plants which ARE sensitive to phosphorus, where phosphorus is toxic and will kill the plant. Kevin Handreck wrote an excellent paper in 1997: ‘Phosphorus Needs of Some Australian Plants’ in the February edition of the journal of the Society for Growing Australian Plants. This paper gives you a list of which plants responded well to additional phosphorus and which reacted badly to additional phosphorus. It is interesting to note that different species within the same genus had wildly different reactions to phosphorus. So you can’t assume that because one Acacia tolerates phosphorus, they all will.

Consult Handrecks lists, and if in doubt, just apply a small amount of balanced fertiliser and see how the plant reacts.

Queensland Fruit Fly

Queensland Fruit Fly

(Queensland fruit fly. Photo © Agriculture Victoria)

Queensland fruit fly is a significant pest that has been found in areas of Victoria for a few years now. Recently there is evidence the fly is establishing itself in Melbourne and surrounds. It feeds on a wide range of fruits and vegetables, and is understandably causing a great deal of anxiety for both home gardeners and commercial growers. Queensland fruit fly from the start of spring and through summer and autumn. They are able to survive mild winters as well.
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Safer Spraying


Herbicides, Insecticides & Fungicides… The safer alternatives

There is a rapidly increasing need to change what we spray and sprinkle around the garden to keep it disease and insect free. It has been evident from the first usage of chemically produced sprays and powders that not only do they kill the insect, fungus or weed that is the problem, they also eradicate helpful flora and fauna that are part of the natural biological chain within the garden. Many gardeners do not realize that when top dressing their garden with super phosphate they are systematically eradicating their extremely helpful earthworm population. The same conditions apply when using chemically produced sprays and powders. The garden’s natural biological structure is totally disturbed so instead of combating a problem it is being compiled. The residue of these sprays and powders build up in the soil, getting into your home produced food chain and poisoning the soil for years.

Healthy plants are less susceptible to pest attack, whether it be from insects and other creepy crawlies or fungal problems, such as mildews. The best way to ensure that you have healthy plants is to have healthy and rich soil, full of decaying organic matter, or humus. Add lots of compost whenever you can – not synthetic all-purpose fertilisers that encourage fast and sappy growth. This lush growth attracts pests far more than steady strong growth and they can quickly ravage the plant you have been cosseting so well. Feed your soil, not your plants.

Growing monocultures in nice straight rows becomes a smorgasbord for insect pests. Diversity in your garden acts to confuse insects. (Diversity doesn’t mean dozens of different varieties of roses!). Overcrowding plants may also contribute to fungal problems as air flow between plants is restricted and fungal spores from one plant spread easily to another. Sometimes even the wrong plant for a particular position weakens the plant and makes it more vulnerable to attack. This could be nature’s way of telling you that you need to cull that plant and put in something more suited to the conditions.

If all else fails and you feel you must really reach for something to help a precious plant survive, there are a number of commercially available insecticides, herbicides and fungicides which are considered safer to use in the garden because they are either biodegradable, herbal-based or consist of elements that occur naturally in the soil. They are usually selective in their eradication of pests, killing the ones that are the problem and leaving the useful insects and the soil clean. They may not “zap” your problem instantly, but they have worked for many.

All of the following alternatives can be found in the nursery or at home in the garden and/or kitchen:

Insecticides

Garlic spray: make up your own (see below) or buy some

Pyrethrum: all are readily available commercially, though one additive to the spray, piperonyl butoxide, is not accepted as organic

Eucalyptus

Derris powder

Sulfur preparations (do not use in hot weather)

Mineral oil sprays (make up your own: see below)

“Dipel” or “Success”: Biological control of caterpillars.

Herbicides

Sulfuric/nitric acid: breaks down within minutes after contact with soil and weeds leaving acceptable residues.

Mulching with Newspaper or non-synthetic carpet under felt. Green manure crops in winter are excellent as these will feed the soil when slashed and allowed to decompose.

Black plastic: Effective but excludes air and moisture which is not beneficial.

Marix weedmat: Very effective in controlling weeds yet allow water and air to penetrate its fabric.

Boiling water poured onto weeds can help kill them

Fungicides

Dusting sulfur: Downy and powdery mildew.

Lime/sulfur mix: Powerful, safe fungicide, also effective against scale, red spider and mites.

Copper compound: ‘Bordeaux mixture’ – very effective but use wisely as it kills earthworms.

Blackspot on Roses

1 litre skim milk (preferable organic because it contains more antibiotic qualities)
1 litre soapy water
Spray on foliage every couple of weeks or so, covering both sides of the leaves and the stems.

Powdery Mildew on Soft leafed Vegetables

4 teaspoons bicarbonate of soda
50 mL white oil
4 litres water
Spray foliage as required

Garlic Spray recipe as a general insecticide

(ref Jane Edmanson’s Working Manual for Gardeners)

Crush several cloves of garlic and mix with 2 tablespoons of paraffin oil. Leave to stand overnight. In a separate container, mix 500ml water with 1/3 cup flakes of soft soap. Strain the garlic/oil mix into the soapy water. Store in a glass container, preferable refrigerated and clearly labelled.

This needs to be DILUTED 10 times with water and then misted over your plants. If it is not effective, dilute less. It is not a contact spray, but must be eaten by the pests. It can sometimes also work as a deterrent.

Oil Spray recipe for sap-sucking insects

Use 2 cups of vegetable oil to 1 cup of pure liquid soap and blend them together until the emulsion turns white. Dilute 1 tablespoon of this to 1 litre of water and spray over insects such as scale and citrus leaf miner. NB Only use this in milder weather as the oil film over the plant can burn the leaves. Scale can also be removed using an old toothbrush!

Methylated Spirits

Used straight, dab directly onto small mealy bugs with cotton wool or cotton buds for pests within the crevices. Mealy bugs proliferate in sheltered positions, usually under eaves or in indoor plants.

Snails and Slugs

Seek out their hidey holes. Long strappy leafed plants are a favourite. If you must use snail baits, choose the ones based on chelated iron, rather than metaldehyde, which is also toxic to children and pets. Put some down into the leaves or make traps with the bait inside.

Do the stomp! When it rains, go out overnight with a torch and a sturdy pair of boots and enjoy the crunch as you stomp your way through the garden. You can eradicate hundreds this way!

Place jars half-filled with beer with the mouth at soil level near seedlings and other plants that are susceptible to snail attack. The snails are attracted to the smell of the beer. They consume it, become drunk, fall into the saucer and drown. Use this method only if you can bear sacrificing beer to snails!

Coffee. It’s a great slug and snail killer. Add to 10 parts water, one part espresso coffee. It has to be espresso because instant coffee is just too weak. Spray this solution over the surface of leaves and over the surface of the soil, where snails and slugs might crawl. The snails absorb the coffee through their skin and the caffeine in it kills them.

Snails don’t like to get their foot dirty! They tend not to travel over some substances such as:

·Shell grit, as is used for chooks and budgies.
·Chopped up hair or
·Sawdust
Sprinkle them around the base of seedlings and other snail delicacies to keep the snails out

Cabbage Moth

The caterpillars that hatch from cabbage moth eggs can eat a whole row of vegetable seedlings to the ground overnight! To stop cabbage moths laying eggs on your vegie seedlings, scatter empty white eggshell halves amongst your cabbages, broccoli, Brussels sprouts and any other crops that get eaten by cabbage moth caterpillars. These territorial moths mistake the eggshells for other cabbage moths and are repelled from the area.

IMPORTANT SAFETY NOTE

As always, check with manufacturer’s specifications and use safety precautions when using any chemicals – even safer alternatives.

Saving frost and cold damaged plants

Saving frost and cold damaged plants

Photo © Bulleen Art & Garden This frost affected Babaco will come back next spring as good as gold. Just leave it alone until spring, then trim off old foliage.

When confronted with the soggy brown / black disaster of frost affected foliage your first instinct is to grab the secateurs and prune away the evidence, but just take a minute to consider. If it is a potted plant that you plan to move indoors for future protection, then by all means prune away the unsightly mess and bring inside. Similarly if it is a soft stemmed plant, it may rot or get fungal issues, so prune it back (if the plant has been cut right down and is remaining outside, put straw or mulch over the soil to protect from further frosts). However, if the plant is a woody or semi woody plant, and there is potential for further frosts, wait until the last frost is over and prune in spring. The old dead material will help protect the undamaged stems. Prune dead material away in spring, and the plant will generally recover.

Don’t despair if your Boston Fern or other fern look totally dead, they can make Lazarus like recoveries. Prune right back and bring inside and it will almost always recover.

Preventing frost damage

This is easier said than done sometimes, but the first step is to keep an eye on the overnight weather minimums via the Bureau of Meteorology. If it looks like the chance of a frost, then I prefer to use a double covering, the top layer catches the frost and the bottom layer protects the plant from the frozen top layer. Also make sure the soil is damp not dry before the frost occurs. If is in an option, bring any susceptible pot plants inside.

Frost and succulents

Many succulents will survive a short mild overnight frost (-1C), they will look damaged (like the pictured Crassulas) and need to be cut back, but they will live. Some succulents, like Sedum reflexum, Sedum sieboldii, Sedum spurium ‘Voodoo’ and ‘Tricolor’ and most of the Sempervivums will tolerate prolonged freezing conditions and look fabulous. If you are in alpine conditions – pick these succulents.

Treating scale on indoor plants

Tips

1. Any plant heavily infested with scale is the Typhoid Mary in your collection. It will be a source of infection and needs to be isolated and treated if you are not prepared to simply bin it.

2. A single treatment is almost never enough. Everyone wants a one shot solution – it isn’t going to happen. Treat fortnightly until you are convinced the problem is eradicated.

3. Scale will stick to both the plant and the pot – even after you have killed them. Pick, scrape and brush them off. They like to hide in crevices and hard to get spots – be vigilant, turn the plant around and inspect from different angles and in good light. Check the pot also, scale will hide in the rim, the base and in the top layer of soil. If re-using a pot, it is essential you disinfect the pot (I put them in the dishwasher).

Treating Scale

Scale are covered in a protective coat, either a hard protective cover (Hard Scale) or a soft waxy covering (Soft Scale). Both types of scale tend to stay put once they find a site to feed from. They hold tightly to the plant, and may need to be brushed or picked off, even after treatment.

Treat fortnightly with cotton buds dipped in rubbing alcohol and brushed over the scale, neem oil (diluted as per bottle instructions) or insecticidal soap sprayed onto the scale. These are all safe to use indoors. Be thorough and persistent. Check all the crevices, nooks and crannies. They are devious little buggers and have made hiding into an art form. If possible, trim off and bin any heavily infested leaves.

Pure rubbing alcohol (isopropyl alcohol) applied with a spray bottle is very effective against scale (and mealy bug) on succulents which are easily damaged by other methods of removal/ treatment.

Scale life cycle is 2 to 3 months, and you can have all stages on the one plant. The eggs are all but invisible and the emerging nymph is also tiny and hard to see, so you may need to treat for 3 months to get all the scale. Stop treatment once you are sure all scale has been eliminated. Check the rim and the base of the pot, plus any decorative cache pots and saucers. If the scale keep coming, then remove top 2cm of soil, disinfect exposed pot, and add in fresh potting mix.