Integrated Pest Management

Integrated Pest management (IMP) is a strategy organic gardeners adopt to protect their crops from garden pests. There are a number of different practises. Although one alone is unlikely to be completely effective, by adopting a number of defence tactics the garden can be protected.

Some examples of successful gardening practise are:

• Plant diversity
• Mulching
• Soil fertility
• Trapping
• Barriers
• Hygiene
• Cultivation
• Plant resistance varieties
• Use organically approved sprays
• Personal physical attack

Plant Diversity

A polyculture (many types of plants in an area) is preferable to a monoculture (one type only). There are three main reasons:

1 some plants provide a refuge for beneficial – predatory insects

2 some plants may act as camouflage for other plants, enticing the injurious insects away

3 some plants may repel insects.

Mulching

The organic gardener’s mantra is mulch more mulch. Some benefits are that mulch:

• conserves water
• protects against heavy rain and wind
• insulates the soil
• Adds nutrients to soil
• Reduces weeds
• Recycles nutrients
• Stimulates beneficial soil flora and fauna

Soil Fertility

If the soil is fertile with a good balance of nutrients, including trace elements and minerals, the plants are more likely to be strong and vigorous. This has two effects (1) they are able to resist attack and appear to less susceptible to attack and (2) they recover more quickly after an attack.

Trapping

Trapping can be very effective. Fruit fly lures put around my property have resulted in there being no fruit stung. There are various types of fruit fly trap: I use a lure (yellow plastic lid) and an attractant in which they drown.

Another form is a sticky trap. A yellow stick or stake is put into the ground and coated with sticky oil. These attract white fly.

Light traps are used at night to catch moths.

Barriers

Fruit trees, pruned to be small, can be covered with a netting to halt the deprivations of birds and if the mesh is small enough most insects. I covered some apple trees to keep the fruit safe from the rainbow lorikeets (parrots) which visit me annually just for the apples.

Barriers of wood ash can keep snails and slugs at bay.

Paper bags are sometime put over individual fruits or trusses of fruits to protect them.

Hygiene

This is a simple matter but one too easily forgone. Clean all tools. Clean secateurs when moving from one tree to the next. Spades, forks and trowels should be washed and cleaned (not on the garden) to reduce the spread of soil, fungi, bacteria, and soil fauna such as nematodes.

Fruit that has fallen early due to attack should be cleared away and destroyed – boiling is good. Similarly, diseased plants should be pulled. If the compost heap is generating enough heat they can be composted and most pathogens will be destroyed. When flowering has finished or the plants have been harvested take them from the soil as soon as possible rather than leaving them to weaken and become infected.

Cultivation

Although mukch is encouraged, there may be times and circumstances when cultivation is needed to control the emergence of insects that pupate in the soil. Cultivation disrupts their breeding and may expose pupae or eggs to the surface where birds prey or sunlight destroys. I have had little birds follow my hoe staying just inches from it as they snaffle up the goodies!

A green manure crop may be incorporated into the topsoil.

Plant resistant varieties

Avocadoes can very susceptible to root rot and we require a variety grafted to a resistant rootstock. With citrus we try to use only plants with Troyer Citrange as the rootstock. When going through seed catalogues (what fun), we look for disease resistance as much as possible.

Sprays

Sprays can be:

1. Plant derived

• Pyrethrum
• Garlic spray
• Rotenone

1. Acceptable chemically derived.

• Sulphur
• Lime-sulphur
• Oil
• Diatomaceous earth

Personal physical attack

One of the most effective ways of getting rid of small infestations before they build up is to pick the offending insects off by hand. Scale insects can be scraped off with a fingernail. Moths can be swatted – one writer comments that he uses a squash racquet

On non-organic farms IMP includes the use of synthetic and dangerous spray – theoretically as a last resort.

Probably, no one method will work all the time but by using an integrated approach the amount of disease and insect attack should be reduced significantly.