Orange growers releasing killer wasps on their enemy

Scientist David Morgan holds a test tube containing the predatory wasp, Tamarixia radiata.

They look like grains of black sand inside a prescription vial.

But each speck is a wasp that is lethal to the offspring of the Asian citrus psyllid, an aphid-size bug that spreads the bacteria that cause Huanglongbing, or citrus greening disease.