DON’T WASTE YOUR TIME PICKING OFF POTATO BEETLES
There are some easier solutions to help you reduce the number of these intruders
Q Last summer I spent plenty of time picking potato beetles — a couple dozen every day — from my garden. They start out small and bright reddish orange, then become large and brown, with black stripes. After some research, I found out that they were Colorado potato beetles. I’ve lived here for 70 years and never seen these pests before. How can I get rid of them? I don’t want to spend another summer picking bugs. If you miss even one day of picking, another plant is gone. Are they only airborne? Can I cover the plant with a net, or what kind of spray treatment can I use? There’s no way I can grow potatoes without getting rid of these bugs.
A Adult Colorado potato beetles are oval in shape and approximately three-eights of an inch long. The area behind their head is yellow-orange and their wing covers are yellow-white. There are 10 black stripes on the wing covers. Females lay clusters of bright yellow-orange eggs on the underside of leaves. The young larvae are brick red with black heads. As the larvae mature, the colour changes to pink, with black heads.
The beetles overwinter in the soil, becoming active in the spring — usually around the end of May. This is convenient timing for the pests, as that is usually the time that newly planted potatoes begin to emerge. The adults feed for a short time, mate, and then lay their eggs. The eggs hatch within two weeks.
Cultural control includes crop rotation. By changing the location of the potatoes you make it harder for the emerging adults to find the plants. This may not be completely effective, but it certainly does help. Laying down a straw mulch can also help. The straw helps confuse the adults when they emerge, and they can actually keep wandering around in the straw, eventually starving to death.
Picking them off is a technique that does work (as you know) but can be time-intensive if you have a lot of the little so-and-sos in your garden.
According to the University of Minnesota, diatomaceous earth can work on this insect problem as well. Spreading the diatomaceous earth around the plants and on the underside of the leaves has proven effective.
You can also try to find Bacillus thuringiensis var tenebrionis — a bacteria insecticide that doesn’t harm beneficial insects, mammals or humans — and spray it on the plants. It’s most effective on the small potato beetles that measure less than a quarter-inch long.
I would use a combination of the cultural controls, such as straw and crop rotation, along with the diatomaceous earth, and then monitor the plants and pick off any survivors.
Q I’ve noticed a white crust that is forming on the edges of my indoor plant pots. What is causing this, and will it harm my plants?
A Water contains salts in varying proportions, depending on the area. These salts, in time, will accumulate and show up as a white or tan-coloured crust or mineral deposit on the edges of pots, or on the inside of the pots at the soil level.
The crust may even form on the soil itself or on the plant stems. If you mist houseplants with water high in salts, a white residue can form on leaves, and this can lead to permanent leaf spotting.
You can control the problem directly by avoiding tap water. Using rainwater or melted snow to water plants is an economical and effective method of preventing salt buildup. You can also purchase various systems for removing salts from your water supply. These include reverse osmosis, deionizing, and distilling systems. You can also pur- chase distilled or purified water from many stores.
If you want to get rid of the existing mineral deposits, remove the plant and soak the empty pot in a solution of equal parts water and white vinegar. After they have soaked, scrub them with a toothbrush or kitchen scrubber. Rinse the pot well before replanting.