Pesticide for Organic Vegetable Gardens
To control pests in an organic vegetable garden you must use organic and natural means. No artificial or chemically processed pesticide is to be used. This excludes all commercial pesticides, fungicides, insecticides and herbicides. Instead, all methods to control insect pests are either biological or chemically natural.
Before I elaborate on these pesticides for organic vegetable gardens, here are two general practices to be observed:
Keep your soil healthy and clean and maintain an ideal sand/clay balance. For organic vegetation, the soil should be slightly clayey as it has more nutrients than sandy soil.
Check on your vegetables daily. Inspect the leaves, roots and general look of the plants. Look out for any wilting, yellowing or traces of insect pest damage or activity (such as the aphid’s honeydew). By doing so, you nip pest problems in the bud.
Here are some common insect pests in your organic vegetable garden:
1. Aphids (also known as greenflies) – they suck the sap from vegetables and other plants and leave a sticky substance called honeydew on the leaves. This breeds a fungus called sooty mold. If aphids attack a plant, it would have withered, yellow leaves.
2. Mealy bugs (also known as wooly aphids) – they also suck sap from plants but are mostly found in humid places.
3. Bean leaf beetle – the adult beetle feeds on the underside of bean vegetable leaves while the larvae attack its roots.
4. Flea beetle – these are small insects with black bodies that chew holes in leaves and leave crisscross markings on them.
5. Squash bugs – insects that attack vegetables like cucumbers, squash, melons and pumpkins.
6. Green stink bug – these flat and green insects attack bean pods, leaving bulging and wart-like spots.
7. Cucumber beetle – these beetles are greenish-yellow in color with either stripes or spots. They feed on vegetable seedlings where their larvae feed on roots and burrow holes through them. These beetles spread bacterial wilt among cucurbit vegetables like cucumbers and melons.
Now here are some ways to control pests in an organic vegetable garden:
1. Biological method
This is where friendly insects destroy the insect pests. For example, the parasitic wasp lays its eggs on the aphid and when the larvae hatch, they devour its host. Ladybirds also attack and kill the aphid and other pests. Other friendly insects include lacewings, praying mantis etc. You can draw friendly insects to your garden by planting flowers or maintaining a weed patch nearby.
2. Horticultural method
This method involves planting certain herbs such as garlic, sage, peppermint and basil that are disliked by pests. This is a good natural way to keep insect pests away.
The horticultural method also involves mixed cultivation (also known as companion planting) of your vegetables. Certain types of vegetables help each other repel insect pests. For example, onions and carrots help each other eliminate the onion fly and the carrot fly. Even flowers can be used. For example, the marigold draws away nematodes from the vegetables.
Another way of dealing with pests under this method is rotation planting. This is where you rotate your vegetables among the raised beds in your garden after each year. This reduces the proliferation of insect pests.
3. Natural chemical methods
In this method, you use natural substances against insect pests. One example is insecticidal soap. Insecticidal soap is made of sodium or potassium salts of either animal or plant oils. Chemically, they are the salts of the fatty acid portion of fats and oils. You can either buy it or make it yourself. Insecticidal soap is very effective against soft-bodied insect pests like aphids and mealy bugs. It can also be used to wash off honeydew stains from the leaves.
Another example is bacillus thuringiensis (BT) or friendly bacteria. There are about 80 types of BT. They are poisonous to insect pests. You sprinkle them on the vegetables and in time, they are consumed by the pests.
As you see, you don’t have to use synthetic commercial pesticides to protect your organic vegetables. That keeps your vegetables uncontaminated by such pesticides.