Citrus growers use predator wasp to fight disease threat
Invasive species expert Mark Hoddle coaxes a vial of predatory wasps to the tip of a citrus branch infested with psyllids. The tiny wasps become parasites to a species of psyllid that has been spreading a deadly bacteria in citrus trees throughout the Southland. More photos
California citrus farmers import a parasitic wasp from Pakistan to battle citrus greening, a disease threatening their groves.
Pesticides haven’t worked. Quarantines have been useless. Now California citrus farmers have hired an assassin to knock off the intruder threatening their orchards.
The killer-for-hire is Tamarixia radiata, a tiny parasitic wasp imported from Pakistan.
Its mission: Rub out the Asian citrus psyllid, which has helped spread a disease that turns citrus fruit lumpy and bitter before destroying the trees.
The pest is wreaking havoc in Florida’s 32 citrus-growing counties. In California, it’s been detected in nine counties, most of them south of the commercial growing areas in the Central Valley. Farmers are hoping the Tamarixia wasp can help keep it that way.
The wasp, which flew coach in a carry-on bag from Pakistan’s Punjab region, is a parasite half the size of a chocolate sprinkle. But it kills psyllids like a horror movie monster, drinking their blood like a vampire. The female wasp can lay an egg in the psyllid’s belly. When it hatches, it devours its host.
The wasp “is going to be our number one weapon to control to Asian citrus pysllid,” said Mark Hoddle, an invasive species expert at UC Riverside, who, over several trips, brought legions of wasps to California.
“We have no other choice except to use this natural enemy or do nothing. And the ‘do nothing’ option is unacceptable.”