New License May Aid Control of Citrus Weevils, Other Pests

Two strains of a tiny, wormlike nematode could give citrus growers a more effective natural way to rein in the serious pest known as citrus root weevil (Diaprepes abbreviatus). Thanks to findings by Agricultural Research Service (ARS) scientists, the commercial production of the nematode Steinernema riobrave has been licensed by BioControl Systems of Greendale, Ind.

Entomologist David Shapiro-Ilan, at the ARS Southeastern Fruit and Tree Nut Research Laboratory in Byron, Ga., with Clay McCoy and Robin Stuart at the University of Florida, found the two S. riobrave strains in Texas and Mexico. The naturally occurring roundworms kill the pests but don't harm people or the environment.

According to Shapiro-Ilan, S. riobrave generally ranks as the best beneficial nematode for biological control applications against larvae of the citrus root weevil in citrus groves.

Native to the Caribbean Islands, D. abbreviatus was first reported in Florida in 1964 and has become a major pest of citrus and many other commercial crops grown in the state. It's sometimes referred to as the diaprepes root weevil.

Earlier this year, Donald Sturniolo, owner of BioControl Systems, licensed the technology from ARS. Since then, the nematodes have been mass-reared and stockpiled for future large-scale trials. These new strains also have the potential to control other important pests, such as plum curculio, pecan weevil and corn earworm, according to Sturniolo.

ARS is the U.S. Department of Agriculture's chief scientific research agency.