2003 Season Review: Household Insects, Honeybees, Insects on Fruits and Vegetables

Tim Gibb, Insect Diagnostician, Entomology, Purdue University

Fruits and Vegetables:
Overall, insect pests attacking fruits and vegetables were at lower than normal levels in 2003. The unusual weather patterns resulted in the appearance of several rarely seen pests, but most of the major pests did not reach normal levels. The cool, wet spring resulted in higher than normal root and seed maggot problems and some aphid species were present in high numbers. Other common pests such as diamondback moth, European corn borer, striped cucumber beetle, corn earworm, and European red mite were present in unusually low numbers in 2003.

Honey Bees:
Honey bee problems continued during the summer and fall of 2003. Rains during the spring, summer and fall decreased the number of sunny days during which bees work and also interfered with the plant/bee interactions (esp goldenrod and fall aster blooms) such that by the time they were producing nectar and pollen, it was too cold for the bees to work efficiently. Due to these and other constraints, many bees failed to make honey in the fall after the first harvest in August. As a result, many hives had very low reserves of honey going into winter and required feeding with sugar syrup. We can expect some substantial losses of bee hives in Indiana this winter due to starvation.

Household pests:
2003 was marked with an increase in homeowner complaints of insect nuisance pests. The unprecedented rains throughout the state increased the habitat for mosquito populations in low lying areas. More mosquitoes were found throughout the spring and summer months, however, certain species of mosquito such as Culex pipiens, (the major mosquito vector of west niles virus) had lower populations in 2003 than anticipated. Interestingly, the reduced Culex population was also thought to be rain related. The behavior of Culex is that it breeds in organically enriched stagnant pools of water. The flooding rains diluted and washed out such preferred habitats, resulting in decreased populations of Culex and a corresponding decrease in the incidence of west niles virus both in horses and in humans during 2003.

Nuisance insect pests in and around homes was higher in 2003 than in most years. Wet conditions in areas where high organic matter exists, fostered a longer and more intense battle with millipedes, sowbugs and pillbugs, especially during the spring and early summer time. Homeowners often complained of these nuisance pests covering sidewalks, patio and garage floors and even entering into basements through window cracks and utility ports.

Incidence of syrphid flies and Asian lady beetles attracted to homes in the late summer and fall is thought to be directly associated with the invasion of soybean aphid throughout the state. Syrphid flies were attracted to homes and yards in unprecedented numbers in late summer of 2003. These flies resemble sweat bees and elicited fears of being stung by many people. The reality of course, was that these are flies, incapable of stinging and presented an annoyance only. Asian lady beetles have become a nuisance pest throughout the eastern United States in recent years. Populations in the mid-west had been abating in recent years until 2003. Increased food resources (principally aphids) in 2003 is thought to have triggered a second resurgence of these pests. Homes and communities near soybean fields were especially troubled by both syrphid flies and Asian lady beetles in 2003.

Cluster flies were much more prevalent inside homes during the fall of 2003. It is likely that the increased precipitation of 2003 directly influenced the abundance of earthworms of which this fly is parasitic. The increase of earthworms then led to higher cluster fly populations. These sluggish ‘house fly-like’ insects will be troublesome throughout the winter and into the spring or 2004.

Boxelder bugs were more common during 2003 than in previous years. The onset of cool weather in late summer and early fall signaled the beginning of the migration of these nuisance pests toward buildings where they seek overwintering shelter inside. Many more complaints of boxelder bugs were received during 2003 than usual.

More insects near homes, patios and gardens also gave rise to an increased population of spiders. Many orb-web weaving spiders inhabited windows sills, bushes, and garages in 2003, likely in response to the greater insect abundance that they prey upon.

Overall, turgrass insect pests were comparatively moderate during 2003. Japanese beetle damage was very spotty, some locations having increased problems and other locations experiencing reduced levels of Japanese beetle pressure compared to previous years. Increased precipitation throughout the state kept turfgrasses greener in the summer of 2003. This diluted the usual concentration of Japanese beetle egg laying to areas of irrigated turfgrass, and thus decreased the amount of turfgrass damage. However, Hoosiers should not be lulled into thinking that the populations were less. More normal weather conditions in 2004 may well yield even greater populations of Japanese beetles than ever.