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Posted 15 February 2010. PMN Crop News.

Could Another Soybean Pest be Right Around the Corner?

Source: University of Illinois Press Release.

Urbana-Champaign, Illinois (February 1, 2010)--Entomologists are always on the lookout for the next new pest that might come our way. For soybeans, the next pest might be the trochanter mealybug, Pseudococcus sorghiellus.


"This insect appears to have been first reported from soybeans in Kentucky during 2008. It has since been found in Iowa and Ohio," reports Doug Jones, University of Illinois Extension pest management specialist. "It is probably in many other locations, but because of its small size and peculiar habits, it could've easily been overlooked."

Mealybugs are an odd type of insect. Females are fat, slow-moving creatures that stay on the plant throughout their lives. Males are winged as adults, don't feed, and only serve to mate with the female. Males are not usually noticed because of their small size and short adult life.

Jones says that mealybugs are often associated with ant species that protect and spread them so that the ants can harvest honeydew from the insect. This frequently complicates their control since they can easily move between plants with the ant's help. They are also prolific and reproduce easily.

Trochanter mealybugs are usually found feeding on soybean roots. They usually have a whitish appearance due to the fluffy waxy secretions that cover their bodies. Their presence was discovered when scientists were trying to determine the cause of potassium deficiency symptoms that, after further testing, revealed no such deficiency.

"If you have soybeans that exhibit the classic yellowing symptoms that are associated with low potassium, it would be wise to pull a couple of plants and carefully examine their roots," advises Jones. "A hand lens will be necessary to adequately identify the insect."

At this moment, it is not known what, if any, consequences these new pests will have on soybeans. Jones says other mealybug species such as the pink hibiscus mealybug, Maconellicoccus hirsutus, or the passionvine mealybug, Planococcus minor, have had large negative impacts on crops such as banana, citrus, cocoa, coffee, corn, grape, mango, potato and soybean in various parts of the world.

Because of the long history of other mealybugs and crop damage and due to the trochanter mealybug's association with potassium deficiency-like symptoms, soybean growers should probably take notice.

Douglas B. Jones