   Early Season Insect Activity - March 20, 2002 Jeff Schalau, County Director, Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County Have you ever wondered what happens to the insect specimens that baffle Master Gardeners and Extension Agents in local Cooperative Extension offices? They get packaged up and sent to Carl Olson, University of Arizona Entomology Curator (otherwise known as "Bugman") for identification. Carl has been doing providing this service for several years and, as a result, Carl is very familiar with most of Arizona's insects. Carl grew up in the Midwest but gravitated toward Arizona because of the incredible insect diversity found here. I know that most people have an aversion to insects, but not entomologists. This is especially true of Carl whom I affectionately call "bug hugger". This week, I just happened to be going to Tucson for a meeting and brought some insect samples along for Carl to identify. As it happened, I caught him at a good time and we had a chance to visit for a few minutes before he looked at my samples. His office is stacked high with jars of insects, various insect nests, and photographs of interesting insects and field excursions. The insect collection is housed in an adjacent room, which is filled floor to ceiling with cabinets stacked with specimen cases. Each insect in the collection has location and collection date. I would guess that there are 10-20,000 or species in the U of A collection. I brought three insect samples and Carl quickly identified them under his dissecting microscope then verified them by comparing them to those preserved in the Entomology collection. We discussed them and the potential risks they posed. Carl has much of this information in his head. He also referred to his extensive library. Details of these three insects and their habits/preferences follow. Two of my samples were winged ants: one black, one red. Ants can swarm like bees to start colonies in new locations. The large (1/2 inch long), black, winged ants were Carpenter Ants. These were collected inside a home in Sedona. Carpenter ants are a concern because they can eat partially decayed wood and/or paper. This material is often a part of a house or other structure that has been exposed to weather or water damage. Carpenter ant activity can weaken structures, which can lead to structural safety concerns. If you have carpenter ants, locate the point of entry and monitor their activity. Look for leaks, openings, or otherwise damaged areas that attract carpenter ants. Do-it-yourself treatments can be applied. However, these may not completely eliminate carpenter ants. If a carpenter ant infestation persists, call a pest control professional for assistance. The second sample contained winged red ants collected in Lake Montezuma. They were swarming around the client's home and causing a general nuisance. Carl identified these as harvester ants. Harvester ant nests are easily identified: a large soil mound surrounded by a 6-8 foot zone completely devoid of vegetation. The winged stage cannot bite. Conversely, harvester ant workers are usually reluctant to attack but can deliver a painful stinging bite. The effects of the bite can spread along lymph channels and be quite serious. When left undisturbed, harvester ants forage for plant seeds and dead insects bringing them into the underground nest as food for the colony. I have some harvester ant nests at my house. If they are located out away from areas of human activity, I leave them. Horned lizards feed on harvester ants and I have noticed more horned lizards in my yard since I left a couple of nests. I only control them when they pose a direct risk to humans or domestic animals. This can be done with Amdro® Pro Fire Ant Bait (active ingredient: hydromethylnon). The ants think the bait granules are seeds and transport the bait into the nest as they would seeds. This product works extremely well, but I would carefully weigh the needs and risks to non-target organisms before applying. The third sample was a jar of moths collected in the Humboldt/Dewey area. Our Prescott office has gotten several calls reporting thousands of these moths. The moths were mostly gray and the hind wings show six white spots (three on each side). This moth is called Litocaula sexsignata (no common name was given). They appear to be harmless and the literature said their primary food source is oak. I don't know for sure, but must assume that these moths are feeding on oak brush that is common in chaparral areas surrounding Humboldt/Dewey. They were also seen in that area last year. To see a color photo of this moth, go to the Pest Diagnosis Archive on the Yavapai County Cooperative Extension web site (ag.arizona.edu/yavapai/diagnostics/). If you have an insect sample that you would like identified, please put it in a jar and bring it your local Cooperative Extension office. You will need to fill out a form, which details the environmental conditions and control measures taken. Insects can easily be killed and preserved by immersing them in isopropyl (rubbing) alcohol. If we cannot identify it in our office, it can be sent on to Carl Olson through our office. Currently, the service is available at no charge. However, there have been discussions about charging a small fee for insect identification to help with associated costs. Given our current state budget crisis, this is a strong possibility. For this reason, only bring in insect samples that are causing a significant problem or concern. Most insects are beneficial and have an ecological role in the environment. More often than not, people kill insects because they don't understand them. On some occasions, control measures can be justified. Before applying an insecticide, identify the pest, and then ask yourself if you can tolerate a low level of damage or nuisance. Many insect conflicts can be prevented by properly maintaining our homes: screens, doors, weather stripping, roofs, and caulking. In the garden, healthy plants can usually tolerate some damage and often beneficial insect predators and parasitoids will provide control pressure. What do you know…now I sound like a bug hugger. I guess Carl Olson's philosophy has rubbed off. The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at mgardener@verdeonline.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://ag.arizona.edu/yavapai/anr/hort/byg/. |