Control pests organically.
WHAT'S A PEST?
An insect can become a pest when it causes economical damage to homes, crops.etc. This happens when there is not enough diversity in the surrounding ecosystem to support the predators which in a natural system would keep the pests in check.
WHY CHEMICAL PESTICIDES ARE BAD.
Human health and environmental health are affected by use of chemical pesticides. There is a multitude of toxins around in cleaning products, aerosols and commonly used pesticides on foods to make them look and last better.
These products can reduce our immunity to everyday viruses, bacteria and common allergens, and in combination with 'background' levels of pollutants can have unknown consequences on health- no one really knows because the chemicals have been around for a relatively short time.
DDT showed what unknown new chemicals can cause.
UNEXPECTED RESULTS OF USING POISONS.
1/ Imbalances can be caused in other parts of the garden and non-target species in the food web will also be affected by use of poisons.
Even least-toxic choices can damage or kill beneficial insects populations if used carelessly. Poisoning may even cause an influx of the same or different pest species the next year.
There are numerous interactions in a garden which may not show for some time as beneficial insects can take a while to show up and settle in. There needs to be plenty of food for them to stay.
If you use poisons pest numbers rise because beneficials have died.
2/ Insects can form a hereditary resistance to toxic sprays that are commonly used against them. Some species show signs of vigour when sprayed with their favourite poison. In some cases the exposed eggs of an insect will show signs of resistance as an adult.
TOXIC POISONS STILL ON THE MARKET.
Round Up, claims to be fairly harmless to the soil, breaking down fairly quickly into lesser chemicals but it can still damage life away from the target area if spray drift or a spill occurs into a pond or waterway, and through poor disposal practices.
The surfactant, used to make sure the product mixes with water and stick to leaves increases its damage to water life - fish, frogs and dragon fly nymphs, as it absorbs through their skin.
Organophosphates are more toxic but have a shorter persistance than the banned organochlorine compounds. They are both nerve poisons. It can easily be accidentally absorbed through the skin.
WHY USE ORGANIC METHODS? WHY ORGANIC IS GOOD?
Encouraging diversity in your garden is the best way to control pest populations. Killing insects willy-nilly with chemicals decreases diversity.
Diversity increases predators such as skinks, spiders, wasp and flies, mantids etc, reducing the pests as they satisfy their food needs.
Plant diversity allows some plants to survive when others get diseased or eaten. It is important to have things in flower at all times of year so nectar is always available.
Balance is easier to attain in a diverse environment.
IMPROVING CULTURAL PRACTICES IN THE GARDEN.
Generally the worst problems will occur in new or neglected gardens or those with a history of chemical abuse. It can take 3 years for balance to occur.
Choose appropriate plants for your climate, time of year and soil type. Certain varieties will be more locally adapted than others, if they've been grown there before.
Look around at other gardens to see what does well and isn't being bothered by pests.
Grow local plants that the local insects know and which will be controlled by local birds.
There may be disease resistant strains of the plant you like.
Plant early and/or late varieties: works to avoid pests such as Med fruit fly. You might just miss the time when the pests want to bother that crop.
Grow lots of flowers from the Asteraceae family (daisies, chrysanthemums, cosmos, etc) and the Apiaceae family (dill, fennel, carrots, Queen Annes lace, yarrow, angelica, coriander, parsley) to feed hoverflies, and wasps etc.
Avoid monoculture. Plant similar things or groups of things around the garden; not altogether or in rows that a pest can easily follow and decimate. Planting in a number of spots means if they find one they won't find all the others, and also if some get diseased they won't all pass it on to each other.
Crop rotation stops a host plant being in the same place when eggs hatch the next year from adults that fed on the last seasons crop. There can be problems associated with nematodes when crop rotation doesn't occur.
Improving the soil and feeding plants well will grow healthier, stronger and more pest resistant plants. A healthy plant can (somehow) increase its bitterness, when nibbled, to deter its nibblers. Overuse of nitrogen fertilizers encourages aphids etc as they suck sappy new growth. Kelp seems to increase leaf strength.
Observation is important in all stages of pest control, to make sure you won't kill more than just the pest. Use a magnifying glass to aid identification and to see if aphids, etc are already being parasitized by wasps, etc.
Garden hygiene: some weeds encourage pests by providing homes.
LIFE CYCLES:
Learning the cycles of insects by observing what they eat, what time of year they come and the weather conditions will allow you to better identify and control them, by acting at the most sensitive and appropriate stage of their life.
If you garden in the same place for a long time you can learn its rhythms. Keeping a garden diary is handy for ongoing information collecting.
Many pests will explode in numbers as their favourite, possibly only, food source becomes available.
Many overwinter as eggs, in the ground, on a tree trunk or in fruit. Once the conditions are right they quickly emerge in large numbers.
The pests die down again once their favourite food is gone, adults laying eggs for next season.
Less fussy insects go to other weedy species allowing them to carry on breeding, and making them harder to control.
Some plants that can harbour pests are cape weed and sow thistle, though this may vary in your area, or even different bits of the garden.
COMPLETE METAMORPHOSIS.
The insect goes through four stages of growth - egg, larva, pupa, adult, and changes form completely at each stage eg caterpillars, dragonflies.
Eggs are placed by the parent on the larva's favourite food source, so when the eggs hatch they don't have to go far. Easy to squash, but be sure you know what it is. It is often easier to kill a pest while it is still an egg than as an adult. Certainly easier to catch!
Digging over the ground exposes insect eggs and root eaters so the sun or birds can get them, but it also exposes the soil and its organisms to UV which is bad (worms die if exposed to UV).
Frequent digging damages soil structure, but needs doing occasionally to loosen compacted ground and incorporate organic matter. Once fertile, digging is reduced as it's been loosened by plant roots and soil life - worms, etc.
Larvae are easy to collect if they can be seen. Some insects hide their young under leaves or in cracks of bark to make them hard to find.
This is often the most damaging part of an insect's lifecycle, when they eat the largest amount to store up energy for the next part of their life cycle.
Pupa: no damage. A good time to collect if you know what you're collecting.
Collecting adults of the pest, usually at dusk or dawn is an easy way to stop population explosions.
INCOMPLETE METAMORPHOSIS.
The young looks just like the adult only smaller, each time it moults it grows bigger, eg cockroaches, grasshoppers, earwigs.
PARTHENOGENESIS.
Unfertilized females give birth to more unfertilized females, building numbers up rapidly to plague proportions. It cuts out breeding and egglaying and the need for males. Many scale and aphids populate by this manner.
GENERAL INFO ON TYPES OF PESTS
PEST POPULATION EXPLOSIONS.
Many pests will explode in numbers as their favourite (or possibly only) food source becomes available. Many overwinter as eggs, in the ground or on a tree trunk. Once the conditions are right they quickly emerge in large numbers.
Types of pest by damage done:
* Leaf eaters: The most common garden pests, seasonal. Cause chewing damage on leaves, frass piles beneath where they are on the leaf.
* Sucking insects: These have piercing and sucking mouth parts, often feed along the central veins of a leaf. They may cause only minor primary damage, but can spread viral diseases. Sometimes appear in plague proportions as eggs all hatch at once when conditions are right.
* Root feeders: Root maggots cause damage to plants as they feed on roots, stopping water and nutrient absorbtion by the plant, which wilts and won't recover no matter how much its watered.
With potplants try placing in water above soil level til they float out.
Crop rotation prevents a lot of these problems as the food source won't be available when the last season's eggs emerge. Many eggs are laid beneath the food plant.
* Borers: Identified by dry, woody frass collecting at entry point. Some trees are more susceptible than others.
* Fruit feeders: Hatch mainly from eggs laid in fruit. Cause huge amounts of damage to crop. Most common in Perth is the Mediterranean Fruit fly.
You need to learn lifecycles of these pests, so they can be controlled at the right stage.
* Viruses or fungal spores can also be spread by sapsuckers and other insects.
GOOD ONES: BE BETTER TO BENEFICIALS FOR YOUR OWN BENEFIT.
Many creatures are beneficial- birds, lizards, frogs, bats and tiny wasps, hoverflies and mantids and lots more.
Most are predators while many wasps are parasites.
Pollinators are also very important, and many insects help with this important job. These too suffer from poison use.
MANY BENEFICIAL INSECTS ARE EXTREMELY SENSITIVE TO ANY CHEMICAL USE AT ALL.
It is generally the young of beneficials that do the pest control, eating themselves silly as they decimate a population of aphids, scale etc.
Predators can be encouraged by providing habitat such as piles of rocks, logs for lizards and snakes, undisturbed perennial flowering shrubs and committed non-use of chemicals.
Ponds should always have sticks or plants poking out of the water, so lizards can escape if they fall in while drinking. Many birds and insects use ponds in summer. Birdbaths are also frequented by bees, wasps and other flying things (though mine gets frogs in it!)
Birdbaths need to be cleaned really well once a week to reduce risk of bird diseases and mites spreading.
Attract birds in with native flowering shrubs, bird baths, and by providing shelter such as prickly shrubs and fruiting species.
Ideally these areas should never be disturbed.
Provide stakes or other perches for them. They learn to watch when you turn compost or mulch and will soon learn to take advantage of any soil disturbance coming in to clean up slaters and other things.
A bird feeding area can be good as long as they don't become reliant on it. Scatter seed so they don't get crowded.
Chickens digging and scratching can reduce root and fruit pests and expose overwintering insect eggs. Stems that are covered with aphids etc can be fed directly to chooks. Chickens can also help with composting etc, but they can also harbour pests, and need looking after properly.
TYPES OF GOOD INSECTS.
* Hoverflies (Syrphid flies) will often wait until aphid populations are quite large before going in for their dinner, so waiting a little longer before spraying can be of benefit; they are very susceptible to pyrethrum sprays.
* Tachinid flies: There are more than 400 types in Oz, some tiny, some as big as blowflies - they look like house flies but are more squat and hairy.
* Parasitic wasps: There are many types from quite large to less than a millimetre, they parasitise many creatures, including beetles and caterpillers. The smaller wasps lay their eggs in aphids.
* Beetles eat a variety of flying and crawling pests. Highly beneficial insect order.
* Lacewings feed on honeydew, nectar and pollen and some types eat insects. The larvae love to eat aphids, red spider mites, scale and other soft-bodied pests. They lay eggs on single stalks.
* Ladybirds and their young eat aphids, scale, mites, thrips and lerps.
* Frogs eat huge amounts, including green vegetable bugs and cockroaches.
* Centipedes eat soil dwelling organisms and slugs.
* Millipedes feed on rotting plant material .
* Dragonflies: catch many different insects from mosquitoes and flies to butterflies, and their larvae eat many, many mosquito wrigglers.
* Lizards: ants, beetles, fleas and their eggs and other small insects.
soil organisms: including friendly nematodes, microscopic roundworms which increase readily in humus rich soil. They kill more than 200 types of pest, including cutworms, root maggots and other underground pests, but they don't damage worms or plants.
INDIVIDUAL PROBLEM PESTS AND FIXES (AND WHAT THEY'RE REALLY DOING!)
* Aphids provide year round food for garden predators, like ladybirds.
* Ants herd aphids, which produce sweet honey-dew. Ants carry aphids from plant to plant, spreading the pest and viral diseases. Banding can stop ants, as can boiling water in their nests (maybe mixed with borax or pyrethrum). They can be drowned out, by keeping the nest moist for a few days (on slow trickle).
Ants eat flea eggs and are the desert equivalent of worms, so they should be allowed to some extent and only dissuaded rather than killed.
* Cats eat many lizards, frog, birds, etc.
* Cockroaches: hygiene is best control as they are mainly after food particles.
* Fruit fly: size of holes in traps must keep out non-target species. Best to use only specific fruit-fly bait, so beneficials don't accidentally get it.
* Green vegetable bug: damage tomatoes, beans. There is a parasitic wasp that gets them, it was introduced and has reduced their numbers.
* Mites: sulphur.
* Rats and mice: trapping- sticky traps, Deb,
* Slaters are blamed for killing plants when they are actually just trying to get rid of fungus, etc which may already be killing the plant. A sick plant is much more susceptible to insect attack. Slaters enjoy mulched gardens, which have lots of humic activity happening. They also aerate the soil- improving water infiltration.
* Snails mainly a problem for people who water in the evening a lot. Best collected by placing orange halves, or planks around. They feed lizards, frogs and rats. Bribe or pay a kid to collect them. Best time to collect is evening, an hour or so after dusk.
* Scale: use white oil, or meths on a brush.
* Thrips: may be killed with pyrethrum, but they also be get eaten by small wasps and spiders.
GETTING RID OF PESTS (IF YOU MUST POISON)
HANDPICKING
The least toxic approach there is!
TRAPPING
There are many simple traps, such as empty upside down orange halves to catch slaters, pots with straw or paper to catch millipedes.
Many insects are attracted to yellow, so sticky traps are made using yellow cardboard.
COLLARS: cardboard around a tree stem to collect pests (caterpillars, earwigs) beneath.
BIOLOGICAL CONTROLS
* Bug spray: collect some of the problem pest, mash or blend with water, dilute, spray onto pests and plant.
* Bacillus thuringiensis (Bt): kills caterpillars only.
* Pyrethrum spray: highly effective against many roaches, flies, aphids, fleas, thrips, whitefly and others. It works by direct contact and ingestion. Lizards, bees, ladybirds, and the larvae of ladybirds, lacewings and hoverfly larvae are also killed by it though, so it should not be used unless vitally necessary. It breaks down very quickly. Some people are allergic to it.
FUNGICIDES
These also damage useful fungus in the soil, so should be used sparinglly and with care, and try not to let too much hit the ground.
* Sulphur is useful against fungal diseases; it is available as wettable sulpher, which is sprayed on or dusting sulphur.
Wear a mask, goggles and other protective clothing.
Do not spray within a month of horticultural oils. It makes alkaline soil slightly less so and makes phosphorus in the soil more available.It can kill parasitic wasps and predatory mites.
* Urine watered down with water to a ratio of 1:20-30.
* Milk watered down 1:9. This works by creating bacteria that eat the fungus.
* Casuarina needles can be made into a spray to reduce fungal attack.
* Chamomile is good against fungus and is used to prevent damping off in seedlings.
* Condy's crystals: potassium permanganate: a powerful fungicide (kills tinea), which kills many fungal species, including some hard to kill soil-borne tomato diseases and beneficial soil organisms. Easy to apply and use, is not dangerous to handle, and ends up as K and Mg.
It does kills worms, only where applied and the effect goes away quickly. Use as a last resort.
HOMEMADE SPRAYS
There are various homemade sprays that can be used to make the plants taste bad to insects. Some feed the plant too, which increases its pest resistance. Most of these have a short toxic lifespan and need to be reapplied frequently as they only kill the insect by contact.
How poison gets in.
Contact
Through skin by direct spraying onto pest or when it walks on surface sprayed area. ingestion: by ingesting poison bait, or when it cleans itself later.
Systemic.
The whole plant or animal (eg, fleas on dogs) becomes poisonous to the problem insect after ingestion, or other type of administration. Neem is said to be in this category.
It is important to decide whether a thing needs controlling at all. Doing nothing may result in better control than spraying. Just give the predators a chance to find the pests.
Consider the least toxic approach first.
Consider the least toxic approach first as even simple solutions can create feedback loops of different pests, or less beneficials if applied wrongly.
Hover fly larvae are killed when sprayed with soapy water, copper used to repel snails stops worm activity (and stays around for a while), sulpher sprays kill parasitic wasps and predatory mites.
Aphids can be removed with a strong blast from a hose. This may put them off altogether, but be careful they don't end up spreading onto other plants.
The next step could be to spray with soapy water, or milky water, both of which act to clog the spiracles of an insect so it can't "breathe". It is best to test spray to make sure it won't burn the plant.
Use a very weak solution of an environmentally safe detergent or soap with plenty of water. This needs to hit the pests directly.
Observation beforehand will tell you if there are good bugs there and if there is you could let them clean up instead.
Bees and ladybirds are affected by soapy water so spray in the evening or early morning before they get to work.
Watch spray drift, even of low-tox stuff.
Spraying anything means it is fine enough to breathe in; be aware of this and don't stand where drift can get you if it's anything worse than water.
Wear protective clothing, a mask and goggles.
It is best to spray in the early morning or evening as less beneficial insects will be around and it reduces the chance of leaves getting sun scorch.
Plants for pest control/home made sprays.
Many of these things need repeated spraying, especially after rain or watering.
Kelp.
As a spray kelp increases the plants health and improves its immune system, strengthening leaves and thereby reducing insect attack.
Seasol is a kelp based plant tonic. It works in many ways to increase plant health.
Soap.
Must be sprayed onto pests directly to kill them. Doesn't harm bees, ladybirds or parasitic wasps that come along later but will cause damage if it gets directly sprayed on them.
Milky water
Useful against fungal problems.
Elderberry.
Flowers all year which is good for beneficial insects, and the leaves make a potent poison brew.
Casuarina needles.
Turn into a tea and spray on. It can be used instead of horsetail, provides silica to strengthen plant cells.
Garlic.
Blend garlic and water. Strain. Spray on plant.
Chilli.
Blend chilli and water. Strain. Spray on plant.
Hot water.
Boiling water can be poured onto ant nests.
White oils.
A mix of vegetable oil and water emulsified by vigorous mixing. It is used to suffocate insects through direct contact.
Works against mealy bugs, aphids, scale, mites, whitefly, psyllids and also kills the eggs of critters as they overwinter in cracks on trees,
or in curled up leaves. Insects get no resistance because they die. No harm to humans or other mammals.
Winter oil is heavier and doesn't evaporate as easily. It is used on dormant trees to kill overwintering eggs, etc.
Summer oil is lighter and evaporates easily so it doesn't clog the leaves. Can be used any time of year.
Only use these when temp is below 30 deg C. and make sure the plant is well watered beforehand.
Not all plants tolerate oils on the leaves.
Copper solutions (Bordeaux).
Spread a plastic sheet beneath the tree to catch droplets and stop it going in the ground as toxicity can build up after a few years. It repels worms from the soil and stays around for a long time. A little is okay on deficient soils.
Summary
A change in attitude can mean you see an exploding aphid population as an important food source for your garden's helpful insects, wasps, etc instead of as an enemy to be wiped out. A lot of predatory insects are really interesting to look at and to learn about; and there's plenty to know.
Have fun in the garden.
Vicki B
BOOKS
'Organic Gardening' - Peter Bennett.
'Tiny Game Hunting' - Hilary Dole Klien and Adrian M. Wenner; adapted by John Dengate.