New bacterium could harm gypsy moths

USDA’s Agricultural Research Service discovered a bacterium that is toxic in varying degrees to the gypsy moth.

Soil rich in decomposed hemlock leaves, collected from the Catoctin Mountain region in central Maryland, was the source of the new species, Chromobacterium suttsuga, now called Chromobacterium subtsugae sp. nov.

ARS scientists isolated the microbe by suspending samples of forest soil in water and then plating it directly on growth medium that doesn't contain glucose. Bacteria in the samples initially formed small, cream-colored colonies that gradually turned violet.

Gypsy moth and tobacco hornworm weren’t killed by the bacteria, but their weights were drastically reduced due to feeding inhibition. Gypsy moths eating the bacteria weighed 40 percent less than gypsy moths that weren’t fed the bacteria.

The bacterium also is toxic to other pests including the diamondback moth, Colorado potato beetle, small hive beetle, tobacco hornworm, western corn rootworm and the southern corn rootworm.

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For more: ARS Sustainable Agricultural Systems Laboratory, (301) 504-7199; www.ars.usda.gov.