Ask the Expert: Honey Bees, Brown Widow Spiders and Subterranean Termites
November 25, 2014
November 25, 2014
Q. Honey bees are attracted to flowers on a customer’s tree next to a day care center. The kids there are afraid they’ll be stung. The center wants the tree sprayed. Can I do that if I just have a General Household Pests (GHP) license? We can spray hornets’ nests on a tree, so I think I can. If so, what should I use? J.O., Ohio
A. In most states, you must have a license to spray trees. A GHP license doesn’t work. Therefore, I don’t think you can legally spray trees for bees. The other concern is killing bees, which has been politicized. Most insecticide labels provide directions to avoid killing bees. If you sprayed the tree to kill bees, you might have violated the label directions, too. I’d pass and advise the day care center to contact someone with a license to spray trees. You have an out because of the license.
Q. A school bus sat in a parking lot for three months and became infested with brown widow spiders. I placed dichlorvos strips in the bus and let them sit. Three days later most of the spiders were still alive. Why? What should I try next? G.R., Fla.
A. The strips release dichlorvos slowly. It usually takes four days or more to build up a lethal concentration in the air of the enclosed space. You only waited three days. If you’d waited longer, you might have achieved 100-percent control. I also assume all windows and doors on the bus were closed tightly. The more air exchange you have, the longer it takes to build up a lethal concentration. If time is of the essence, treat the bus with a contact spray and kill all the spiders you can contact. A space treatment is a good adjunct to this. The other option is to leave the strips in place longer.
Q. I treated a house for subterranean termites in April after a swarm. The homeowners found a water leak in August. When they opened the wall to repair it, they found live termites. I learned the previous homeowner treated with something himself a year earlier. I used one of the nonrepellent termiticides. How do you explain the live termites? How long could they survive in the wet wood without soil contact? Why didn’t they die from my termiticide treatment? F.I., Mich.
A. If wood contains more than 20 percent moisture, termites can survive indefinitely. I suspect you found live termites after your treatment because the earlier treatment acted as a repellent, preventing the termites from entering your treated zone. The fact there was a swarm right before you treated suggests the termites were alive and healthy in the house and might have contacted the soil before you treated. Any labeled insecticide injected into the galleries in the exposed wood will eliminate the problem.
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