Plant bug defense simplified [UPDATED]Published 4:37am Monday, January 6, 2014 Updated 6:56am Monday, January 6, 2014
Do you have a flying circus around your house plants? Fruit flies? Nope. You have fungus gnats. Fruit flies are brown with red eyes. These stinkers are brown.
Having fungus flies is an indication that you are overwatering your plants. Now, to get rid of them. First of all, let the top three inches of soil get dry between watering. They lay their eggs in the damp soil.
You can put a two- to three-inch layer of colored rocks, the type used in aquariums, on the top of the potting soil for a dry layer. If the soil is old, chuck it out, scrub the pot with a solution of bleach and water and repot with fresh soil.
You can hang a sticky fly strip near the plant to catch the fliers. A yellow square of stiff paper with something sticky on it hung or stuck in the soil can catch some of them when they are in the flying stage. This is the time when each flyer can lay 200 or more eggs.
To determine if you have so many larvae to actually damage the plant’s roots, lay some raw potato cut into one-inch pieces on the soil. The larvae will collect under the spuds telling you how bad the infestation actually is.
Some people have had luck watering with a solution of 4 parts water to 1 part of 3 percent hydrogen peroxide. Insecticides usually aren’t needed, and why would you spray a poison in your house this time of year. Both you and the bugs will be inhaling it.
Fruit flies must be a worldwide pest. Why else would so many scientists be working to eliminate them? Entomologists at Kansas State University have been cooperating with colleagues at the Korea Advanced Institute for Science, Korea University and the Slovack Academy of Sciences to identify a chemical natalisn in insect brains.
It regulates insects’ mating behavior and reproduction. They are learning to shut it down. Female fruit flies with their natalisn shut down, are too busy grooming themselves to pay any attention to courting males.
Males with their chemical shut down don’t attract females. Either because they can’t smell the female or can’t produce the necessary signal to tell the girl fruit flies “hey cutie, here I am.”
Because natalisn is only present in insects, targeting for shut down could be a friendly pest control strategy.
And then there are aphids. Occasionally you will find them on a house plant but more often outside on a garden plant. You are dealing with more than 1,200 species of aphids known to occur in North America.
Aphids survive the winter as eggs. In the spring, all the eggs will produce only females. Each female will produce 50 to 100 live babies. Even though they only live about a week, the babies will start to produce up to 150 babies in the next month.
There will be several generations in a growing season. Most of them will be wingless, but a few will have wings. This is necessary as many species need one plant for eggs, another for food for the adults.
Near the end of the year, winged males will be hatched. They mate with wingless females who lay eggs for the next year. All in all, that is a lot of aphids.
They damage plants by sucking the sap out. This can cause misshapen flowers, leaves and fruit. Usually all the gardener needs to do is hit the plant with a strong spray from the hose. They are too weak to crawl back onto the plant.
Neem oil or an insecticidal soap works too, but try the hose first. It’s a lot cheaper.
Bev Johnson is a master gardener in Otter Tail County