Acerophagus papayae (left) and Anagyrus loecki (right), parasitic wasps imported from Mexico.

This could be the perfect, real-life representation of the theme for the next International Congress of Entomology — “Entomology without Borders.”

Entomologists from Virginian Tech University discovered a devastating plant pest in India and devised a way to combat it naturally, saving Indian farmers up to $309 million the first year and more than $1 billion over five years.

The papaya mealybug had been destroying papaya, eggplant, tomatoes, and other crops in southern India by causing mold and stunted growth until Dr. Rangaswamy “Muni” Muniappan of Virginia Tech identified the pest and spearheaded a natural control program.

The winning intervention centered on three parasitic wasps from Mexico which are natural enemies of the mealybug that the U.S. government first employed in Florida after the pest spread there in the late 1990s. The wasp lays its eggs inside the mealybug larvae, and when the eggs hatch, the young wasps eat the larvae.

“India’s first efforts to eradicate the papaya mealybug failed,” said Muniappan, who heads up Virginia Tech’s federally funded Integrated Pest Management Innovation Lab program, a venture that works in developing countries to minimize crop losses, increase farmer income, and decrease pesticide use. “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.”

Virginia Tech’s work to stop the papaya mealybug is “an important contribution” to protecting U.S. crops, said Dr. Marjorie Hoy, a University of Florida entomologist not associated with the Virginia Tech study who was instrumental in controlling a Florida infestation.

“It’s impossible for regulatory agencies at the borders to inspect and remove any infested material — they try, but it’s impossible to do it all,” Hoy said. “I’m happy to hear that Virginia Tech scientists conducted an economic analysis. That is so often missing in biological-control projects.”

Scientists first identified the papaya mealybug in Mexico, where natural enemies kept it under control. It was found on St. Martin Island in 1995, and by 2000 it had spread to Florida, the Caribbean, and Central and South America. The pest’s march continued, taking it to Guam in 2002, the Hawaiian Islands in 2004, and to India in 2006.

The first-year cost of the project was $200,000, which is modest compared to the $524 million to $1.34 billion in damages that could have occurred over five years.

Virginia Tech’s Office of International Research, Education, and Development is funded by the U.S. Agency for International Development (USAID).

Read more at:

– Economic impact of classical biological control of papaya mealybug in India

– Invasive papaya pest discovered by IPM CRSP in Asia