Extension specialist studies havoc caused by eucalyptus leaf beetle

The eucalyptus leaf beetle has been wreaking havoc on cut eucalyptus during the last few years in Southern California. University of California extension specialist James Bethke is studying life cycles, chewing damage and pesticide use at a trial garden. He’s trying to determine how the pest overwinters -- as an adult, egg or pupa in the soil.

Adult females lay batches of 20 eggs on the upper or lower surface of new growth. Hatching larvae disperse to nearby new growth in bunches of two or three per branch. Larvae are difficult to spot and can be found on upper and lower leaf surfaces.

Adults can cause the equivalent amount of damage as about three larvae on new flush growth. Adults are light brown and relatively easy to see.

“From my observations, it appears that the insect is quite susceptible to pesticides,” he said.

Bethke is testing Safari, Orthene TT&O, Marathon II, Arena and Celero as a soil drench; and Sevin SL, Orthene TT&O, Arena, Celero, Marathon II and Decathlon as a foliar spray.

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For more: James Bethke, University of California Cooperative Extension, 5555 Overland Ave., Building 4, San Diego, CA 90123; (858) 571-4204; james.bethke@ucr.edu.