The papaya mealybug is a particularly nasty pest that rips through papaya, eggplant, and tomato crops in southern India, but it’s hard to control since it is resistant to conventional pesticides. Without intervention from the same Virginia Tech team that helped Africa farmers combat the leaf miner moth, the mealybug would have caused $309 million worth of damage in the first year of its invasion, and more than $1 billion over the next five years. Rangaswamy “Muni” Muniappan developed a natural pest control program that wiped out the papaya mealybug’s onslaught in India – all for the modest cost of $200,000.
“India’s first efforts to eradicate the papaya mealybug failed,” says Muniappan. “The government and farmers tried spraying pesticides, but crop losses kept getting larger. It was clear to us that this was a case not for poisons but for natural, biological controls.” That’s when the team turned to three different kinds parasitic wasps from Mexico that lay their eggs inside the mealybug larvae. When the eggs hatch, the young wasps feed on the larvae and prevent the mealybug’s population from spiralling out control.
The biological control was inspired by the U.S. government, which first made use of the parasitic wasp in Florida during the late 1990s when the mealybug took up residence. Papaya mealybugs are thought to have originated on St. Martin Island, and have since spread to many other countries, which makes India only the latest in their long history of invasion.
Muniappan is in charge of Virginia Tech’s Integrated Pest Management Innovation Lab program, an organization that was also instrumental in organizing workshops to prevent the spread of leaf miner moths across Africa. Stephanie Myrick of Virginia Tech’s College of Agriculture and Life Sciences and representatives from Tamil Nadu Agricultural University in India contributed to the research to control the papaya mealybug in India.