Two tiny wasps from South America are among the top candidates as biological controls for the glassy-winged sharpshooter, a pest that attacks citrus crops and has caused problems for grape growers in California.
The pest has bred in large numbers in southern California, a region that lacks most of the insect's natural enemies. Agricultural Research Service entomologist Walker Jones at the Kika de la Garza Subtropical Agricultural Research Center in Weslaco, Texas, is leading an international effort to find nonchemical methods to stop this invasive leafhopper.
Sections of South America, particularly Chile and Argentina, have climates that are very similar to those of some of California's prime agricultural areas. Some of those sections of South America also have sharpshooters that are close relatives of the glassy-winged sharpshooter. Given the similarities to California climates, South American biological control agents should already be pre-adapted to the Golden State, according to Jones.
In a 2002 search of northern Chile and northwestern Argentina, Jones and colleagues found more than a half-dozen such natural enemies of South American sharpshooters.
Their top two biological control prospects have turned out to be tiny wasps, Gonatocerus tuberculifemur and G. metanotalis. These wasps have been known to attack the eggs of a South American sharpshooter, Tapajosa rubromarginata. This insect is very similar to — albeit slightly smaller than — its glassy-winged cousin.