In this post, we examine the different ways to control farm pests that prevent you from enjoying the fruits of your labour.
Whilst many pest and disease problems can be prevented, there are various occasions where pest or disease numbers increase to such high numbers that they can cause serious damage to your crops. It is crucial to properly identify the culprits. Sometimes innocent bystanders who happen to be at the scene get blamed for an act that pests are responsible for.
Here are a few effective ways to manage pests on your farm.
Mechanical controls include barriers that keep pests away from your crops. There are various types of netting available to protect your vegetables (fleece, crop covers, bird netting, etc.). It’s important that you use the right type of netting for the relevant pests. A net to keep the small carrot root-fly out needs to be a lot finer than a net for cabbage white butterflies.
Collars are used around brassicas to prevent the cabbage root-fly from laying its eggs near the cabbage stems.
Many pests can be lured into traps. The beer trap for slugs is a popular example. If you use this method ensure that the lip of the container is above the soil surface otherwise you may also catch some ground beetles which would have eaten many more slugs than you have caught. Personally, I can think of a much better use for beer!
You can also buy yellow sticky tape from garden centres to catch flying pests such as aphids. They are very good as indicators to find out which pests you have but they will not control pests sufficiently.
Handpicking larger pests such as slugs, leatherjackets or caterpillars can be quite efficient especially in a small garden. I know some gardeners who get great satisfaction from this.
Biological control includes attracting beneficial creatures that feed on pests as well as introducing predators for the job! These predators can be purchased by mail order but are generally very expensive especially for a small area.
It is much more efficient (and a lot cheaper) to attract native beneficial creatures into your garden than to purchase foreign species.
Examples of natural predators include:
Hoverflies – the larvae and adult hoverflies feed on aphids
Lacewing – feed on aphids
Ladybirds – feed on aphids
Beetles – feed on slugs and many other small pests
Earwigs – most people believe they are pests but they also feed on aphids
Frogs – feed on slugs
There are a number of so-called ‘safe’ organic sprays available to the gardener. They are safe in the way that they are fully biodegradable within a couple of days (with the exception of copper sulphate) but nearly all of them will also kill beneficial insects and thus disrupt the natural cycles. The garlic spray (Envirorepel) is one exception. It only masks the smell of host plants so that pests find it less attractive or get confused. Apparently, it also strengthens the plants so that they become more resistant.
A milk/water spray (1 part milk and 7 parts water) was probably the best new discovery in organic disease control. I have successfully used it to control diseases such as grey mould and mildew on a variety of vegetables. You can spray it with a little plant spray directly onto affected plant parts ideally three days in a row and the disease stops spreading further. Unfortunately, it didn’t work for potato blight.
Other organic sprays include:
Derris – to control aphids, caterpillars, flea beetle
Pyrethrum – to control aphids, caterpillars, flea beetle
Insecticidal soap – to control aphids, whitefly, spider mites
Softsoap – to control aphids
Quassia – to control aphids, apparently safer than derris and pyrethrum
Bluestone (copper sulphate and washing soda) – to control potato blight, apple scab
Sulphur – to control powdery mildew, rose blackspot
Note: All these sprays can also damage beneficial insects or can be harmful to fish, livestock and worms (i.e. Bordeaux mix)
Home-made sprays: Home-made sprays are often prepared by hobby gardeners to control various pests and diseases. They are illegal in places like the EU as they are not tested. Some of them are extremely toxic (rhubarb spray) to all sorts of wildlife. The most interesting spray is a compost tea or extract. You soak one part of compost with ten parts of water for about a week and stir it daily. You then dilute it with another 10 parts of water before spraying it onto susceptible crops to prevent or halt fungal diseases. Many scientists all over the world achieve tremendous results in controlling a large variety of diseases. But remember you are not allowed to make it yourself.