From the Farming God’s Way Vegetable Guide:
Repellents
Preventative measures are by far the best way to combat pests and diseases, as they stop outbreaks before
they occur. If you have had a history with a particular pest in the field in the past, then you should apply
repellents every 7-14 days to ensure they do not become a problem in the current season.
Plants such as marigolds, petunias, lemongrass, basil, rosemary and mint, amongst many others, are great
for repelling problem pests in the garden. These can be easily incorporated into the design of the garden,
either in rows or at intervals, throughout the garden.
Onion, chilli and garlic sprays are excellent pest repellent options. There are also many essential oil plants
that have aromatic repellent properties including neem, orange, eucalyptus, lemongrass, lavender, sage,
rosemary, thyme and clove oil. Many of the mixtures of repellents double up as control sprays.
Spot Spraying
Most people when they see a pest outbreak, will just go ahead and spray the whole field, which is really not
the correct way to tackle pest incidence. It is preferable to spray affected areas as spot sprays to sort out
problem areas, so that they don’t spread into the rest of the field. Remember that these sprays will most
likely kill and repel both beneficial and non-beneficial organisms, so try to limit the ecological damage you
can cause by limiting the spray coverage to affected areas. Spray infected areas with a fine nozzle spray in
the late afternoon to prevent the plants from getting stressed. Do trial sprays of plants to ensure you have
your mixtures correct and don’t cause unnecessary damage. Here are a few examples of hundreds of
available concoctions:
Soap sprays are good at controlling aphids, scale, thrips and mites. Spray directly onto all infested surfaces
to ensure there is a full coverage on the surface of the insects. 2 teaspoons liquid soap per litre of water.
Soap and Oil sprays are more effective as they combine both the effective agent of soap, with the surface
coating effects of the oil, as well as some of the repellent properties to keep pests away for longer. Aphids,
thrips, mealybugs, scale and whitefly breathe through their skin, so a surface coating of oil suffocates them.
The strong smelling repellent properties from chilli, onion, garlic and other essential oil ingredients are
incredibly effective at causing a hasty retreat of pests from the garden.
Option 1 - 1 teaspoon of liquid soap, 1 teaspoon of vinegar, 100ml canola or soya oil and 1 litre of water.
Option 2 – Crush 6 hot chilli peppers (or 2 tablespoons of chilli powder), 2 bulbs of garlic and an onion to a
pulp, add a teaspoon of liquid soap, 2 teaspoons vegetable oil and a cup of warm water. Let it stand
overnight, then strain out the solid particles and top this mixture up with water to make up a litre.
Neem oil (an extract from the Neem tree seed) has become the most widely utilised organic oil spray
against caterpillars, aphids, mites, mealybugs and whiteflies. A simple spray onto the leaves of plants is
enough to disrupt their feeding and lifecycle, and although not instantaneous it will kill pests. Neem oil
sprays have also been found effective at deterring grasshoppers and also controlling powdery mildew.
Neem oil does not harm beneficial insects. 1 teaspoon liquid soap, 2 teaspoons neem oil and 1 litre of
water.
Milk Spray - Using diluted milk and water solutions have proven as effective against powdery mildew as
commercial fungicides. Milk solutions are also effective against mosaic virus, blights and other fungal
infections on squashes, tomato, cucumber and other crops. Mix 100ml of milk with 900ml of water.
Soap and Baking Soda
Baking soda/Bicarb is very basic (high pH) and creates a hostile environment for fungal diseases like
powdery mildew and early blight on potato, tomato and squashes. 1 teaspoon of liquid soap, 1 teaspoon of
bicarb and 1 litre of water. Make sure you test spray before applying to the whole crop.
Bacillus thuringiensis - A commercial option is the use of Bacillus thuringiensis or Bt. Bt is a bacterium
naturally present in the soil which secretes a toxin which is only harmful to certain insect larvae. Bt is
sprayed as a biological insecticide onto the leaf surfaces of many plants and is an excellent biological
control mechanism against certain insect pest larvae with no known side effects on other organisms. Bt has
to be eaten by the larvae in order to work, and once ingested it attacks the gut lining of the insect causing
death.
Dusting
Woodash is very effective in preventing stalk borer and fall army worm infestations in maize/sweetcorn.
Place a pinch of woodash down the funnel of every sweetcorn plant at knee high for “stalk borer” control.
Post harvest stalk lodging is also very effective at exposing overwintering stalk borer to UV light and
opportunistic feeders like guineafowl and chickens.
For the control of “Fall army worm” in all maize cultivars, apply a pinch of woodash every 2 weeks until the
piping stage. This has been proven very effective even when neighbours have had complete failures with
chemical control.
Diatomaceous earth is a fine chalk like powder made up of fossilised diatoms. When sprinkled on insect
pests it sticks to them drawing the moisture away from their exoskeletons, causing dehydration and even
death. It can also be broadcast around the base of valuable crops stems to act as a barrier to cutworm,
snails and slugs.