“Spring is when you feel like whistling even with a shoe full of slush.” —Doug LarsonMost gardeners prefer to use organic insect control as much as possible. This is called integrated pest management. A few of the best non-toxic controls that I have used for many years are sold in most good garden centers.
My favorite is diatomaceous earth. These tiny mineral crystals are sharp enough to cut through the skin of soft-bodied insects like aphids, thrips, slugs, and root maggots. Insect eggs are also very susceptible to DE and its dehydrating power. Early application with a duster in the morning on soil surfaces is effective. The rate is 8 to 10 pounds per acre. In a home garden, a little goes a long way. Dust frequently and especially after rain.
I have found DE very helpful for rootworms on radishes, turnips, rutabagas and for slugs under hostas. For rootworms, sprinkle the rows of vegetables when you plant them. It is non-toxic to humans but be careful not to breathe it in or get it in your eyes.
Another great organic insect control is a caterpillar killer is bacillus thuringiensis. This is safe to use up until harvest. It is used on the larval stages of cabbageworms, codling moths larva, and leaf rollers. It is also used on tent caterpillars and bagworms. It even kills gypsy moths. The timing of your spray is important because once worms work their way into fruit they are unreachable. Spray two weeks after moths appear, just as the eggs are hatching. For cabbageworms, keep a look out for the small white cabbage moths and start spraying at least every two weeks.
Another organic control is Ryanodine or Eight Garden Dust. This is effective control for codling moths. This is a plant resin and is an internal stomach poison that kills leaf eaters. It is also used against corn earworms and borers, houseflies, fruit moths, asparagus beetles, fungus gnats, and fruit flies. It affects pests adversely but is gentle to beneficial insects and safe for mammals. It will not injure plant tissues. Dilute this powder at the rate of 5 tablespoons per gallon of water. When I dilute any chemicals, I use a little olive oil or a small amount of mild dish soap with the product. This helps it stick to the leaves.
Remember to read labels completely. The only chemicals that should be around your home are the ones that are labeled “caution.” If the label says “warning,” protective clothing should be worn. If the label says “danger” that is exactly what is means. Avoid these chemicals if possible. They are toxic to humans and the environment.
There will be a Master Gardener class held this fall if enough interest. For more information, call 608-355-3250.