Organic Vegetable Insect Control
I had maggots in my radishes and beets last year. I had worms in my cabbage and broccoli. I had leaf miners in my lettuce and spinach. Is there a way to prevent these pests without using chemicals?
Yes, we have both cultural methods and new safe organic pesticides which will control these and other common insect pests on vegetables.
The best way to prevent insects from reaching vegetables is to cover them with floating row covers. Floating fabric row covers are lightweight blankets made of spunbonded polypropylene which is permeable to air, sunlight and rain. They prevent adult insects from reaching the plants and laying their eggs. Floating row covers are placed over newly seeded or transplanted vegetables with soil placed around the edges to hold them in place.
They prevent the adult flies from laying eggs at the base of root vegetables and cabbage family vegetables which develop into maggots that attack the roots.
They prevent moths from laying eggs on cabbage family vegetables which develop into cabbage worms. They prevent the flies that lay the eggs which develop into leaf miners from reaching the leaves of lettuce, spinach and other leaf vegetables. They also protect from aphids, beetles and many other insects.
Vegetables can be watered and fertilized without removing row covers. They do need to be folded back for weeding.
Row covers also trap warmth around the vegetables and protect from wind damage, so early growth is improved.
Diatomaceous earth is a natural material which can be placed in the soil when seeding or transplanting or around newly emerged or transplanted root and cabbage family vegetables to prevent maggots.
Three organic pesticides are available which control most vegetable insects without leaving dangerous residues on the plants. My favorite is Spinosad, an organic pesticide which is effective against worms, leaf miners and many other pests. Ask for Spinosad at full service nurseries and garden stores or check labels for active ingredients. Or order Spinosad on line.
Neem oil is another natural pesticide which controls many pests. Bacillus thuringensis (Bt), sold as Thuricide or Dipel, is effective against cabbage worms.
When any of these 3 organic pesticides are applied weekly before insect attack, they prevent most damage to the vegetables.
Allen Wilson
Allen has been writing about gardening for over 30 years. He is a retired professor of Horticulture.