May 14, 2009 at 7:25 a.m.
I also wrote an article on nuisance and harmless insects, and I included the click beetle. Little did I realize that the click beetle in its larval form is a very damaging pest.
I started to realize how damaging they could be when I did some research on potatoes, reading that it attacks potato tubers either killing the plant or damaging the potato itself.
Since I wanted to research the wireworm in depth, I again asked Starr Carpenter, our Horticultural Program Assistant to help. Part of this article is from A. Genetzky, E.C. Burkness and W.D. Hutchinson, Department of Entomology, University of Minnesota.
Wireworms are common throughout the world and can be damaging pests of many different crops, most frequently sod, small grains, corn and beans. They feed on seeds, preventing germination, or on the underground roots and stems of the plants, causing them to wilt or stunt their growth.
There are many different species of wireworms; however, the one that is in my garden is dark brown with a very hard body. In fact, one must squeeze them quite hard to kill them. Their body length is from one-half to one and one-half inches long. The adult click beetle has a narrow body that is one-half inch long and is usually a brown, grayish, or black color. If it gets turned upside down, it keeps flipping until it gets itself right side up, making a clicking sound, and therefore getting its name, click beetle. I have noticed the wireworm in my own garden for the last couple years, but this year there are a lot of them. I have even noticed four to five of them in a cluster and in many areas of the garden, especially in moist soil.
The depressing part is that the majority of the lifecycle is spent underground in the worm stage, which takes two to six years to complete. As the larvae get close to maturation, they will create a cell in the ground for pupation. In a few weeks, they develop into mature adults and remain in the cell until the following spring. The adults will live ten to twelve months, mostly around the sod surface in cracks in the soil and will die shortly after laying eggs. Eggs take anywhere from a few days to a few weeks to hatch and their back in my garden soil for another decade. Generally, the longer it takes for a seed to germinate and grow, the more susceptible it is to wireworm damage. Therefore, it is better to plant seeds when the soil is warm. Commercial growers who find it necessary to plant early may need a seed treatment. However, this type of control only protects the seeds and not the seedlings.
The home gardener can plan for next year's control of wireworms by using baits to find out how serious the problem is. First soak an equal amount of untreated corn seed and wheat seed in water for twenty-four hours to encourage germination, since wireworms are attracted to the carbon dioxide given off by the germinating seeds. Next dig holes six inches deep and from four inches wide. Fill the holes with one cup of the seed mixture and cover up the holes with dirt and then with a black plastic bag. The bag will increase the temperature and encourage germination. Remember to mark the place where you have the traps. Check the traps in a week and see how much of a problem you have. Since most gardens are small, one or two traps in areas where you suspect damage should do
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