DEPARTMENTS


Plant Health



Gypsy moths reach record numbers in Minnesota



Photo courtesy of USDA APHIS PPQ Archive, USDA APHIS PPQ, Bugwood.org

Nearly 70,000 gypsy moths (Lymantria dispar) have been trapped in Minnesota so far this year - with the emphasis on so far. That number has already set a new record, far outpacing the previous record high of 27,858 critters counted in 2009. But it's anticipated that the figure will grow as Minnesota Department of Agriculture (MDA) staff continue to collect the 14,500 traps set around the state earlier this year.

The state has been trapping since 1973, and the first treatment was performed in St. Paul in 1980; since that time, nearly 800,000 acres have been treated, mostly in northern Minnesota. This year's burgeoning population, however, has forced the MDA to reconsider its detection and treatment program. "We have put up a valiant fight for many years and will continue to do so," said MDA Plant Protection Director Geir Friisoe. "These numbers tell us the battle plan must begin to shift. We go from keeping gypsy moth out of Minnesota to containing and slowing the spread of the insects that are here."

The state will continue to control the resident population with the biocontrol agent Entomophaga maimaiga, a fungus that has proved to kill the insect if ingested. (A fascinating and rather icky video of the process can be seen at http://blog.mycology.cornell.edu/2009/03/18/entomophaga-maimaiga-the-caterpillar-killer/)

Gypsy moth was first detected in the U.S. in 1869 and has spread throughout the eastern part of the country. At present, counties in 20 states and the District of Columbia are under Federal quarantine. With an appetite for about 150 primary hosts and more than 300 species of woody plants, this ghostly little pest poses a significant risk.

Whitefly affects Florida standard



Adult Bondar's nesting whitefly.
Photo courtesy of Lyle Buss, University of Florida

Ficus growers in central Florida are warned to be on the lookout for two whitefly pests that appear to be moving into the region from south Florida, according to entomologists at the University of Florida. Ficus whitefly and Bondar's nesting whitefly have been relatively common in the southern part of the state, although the latter is a newer discovery, having been confirmed as recently as late 2011.

Leaves infested by Bondar's nesting whitefly (Paraleyrodes bondari) eventually develop a coating of black sooty mold, and strands of white wax accumulate as the pupae mature. In a twist on the normal path of whitefly presence, both the upper and lower surfaces of the leaf can be infested. The term "nesting whitefly" comes from the characteristic pattern of wax that forms on the leaf surface around the whitefly pupa.

A whitefly infestation of fig can result in aesthetic damage, including yellowing of leaves, sooty mold and defoliation. Severe cases can result in death of the tree, especially when the figs are planted in close proximity to form hedges.

More information can be found at http://www.flwhitefly.org.