Gardening With Allen: Organic pesticides control many bugs
By Allen Wilson for The Columbian
Published: May 29, 2021, 6:00am
Share:
I have leaf miners ruining my lettuce and maggots ruining my radishes. Is there any control for these pests that does not leave dangerous chemical residues on my food?
Yes, there are three wonderful organic pesticides that are completely safe to use on food crops and around children, pets and wildlife.
Spinosad is a compound derived from a bacterial species originally found on sugar cane. It is an organic pesticide with uses including cat fleas as well as for food crops and ornamentals.
It controls a wide range of insect pests including leaf miners, root maggots, borers, caterpillars, codling moth (apple worms), beetles, thrips and many more insects.
For leaf miners on lettuce and other leaf vegetables, spray the leaves at the first sign of damage. Repeat application at weekly intervals.
For root maggot control, spray the soil around plants of radish and other root crops as soon as seedlings emerge from the soil. It can also be sprayed over seeds before they are covered with soil.
To prevent wormy apples begin spraying fruit as soon as it reaches the size of the end of a little finger and repeat at two week intervals until early August.
Spinosad will also control insects on roses and other woody ornamentals including borers and caterpillars on trees.
The word “spinosad” may not be on the main label. You may have to check active ingredient labels to find it. It will most likely be available at full service nurseries and garden stores.
Bacillus thuringiensis (Thuricide) is an organic pesticide that is especially effective on caterpillars. It is very effective in controlling the cabbage worm which feeds on cabbage and related vegetables like broccoli and cauliflower.
Neem oil is another organic pesticide. Derived from the neem tree, it is effective in controlling major insects as well as a number of leaf diseases. It is my favorite pesticide for roses since it controls both insects and diseases. Spray every two weeks on roses to prevent black spot and other leaf diseases.
Other organic fungicides for plant disease control include lime sulfur, copper and horticultural oils.
