Indonesia signs up wasps to save vital cassava crop

They are the size of a pinhead and don't even sting, but the tiny wasps are cold-blooded killers nonetheless. They will be employed by Indonesia to neutralize the mealybug, a pest that threatens to destroy the nation's cassava crop, one of the developing world's most important staple foods.

Indonesia is the latest country to be threatened by mealybugs, chalky white insects with a voracious appetite that have been making their way across Southeast Asia's fields for the past six years.

But unlike in Thailand, where infestations reached about 250,000 hectares of crops grown mostly for export, cassava in Indonesia is a vital local food source, second only to rice. That makes the mealybug a serious threat to the nation's food security. Indonesia already has one of the region's highest child malnutrition rates.

The parasitic wasps, known as Anagyrus lopezi, are coming to the rescue. They need the mealybug to survive. Female wasps lay their eggs inside the bugs, and as the larvae grow they eat the bug from the inside out, slowly killing it until there's nothing left but its mummified shell.

On Wednesday, scientists put 2,000 wasps in a holding cage in an affected field in Bogor on the outskirts of Jakarta. The wasps will be monitored to see how well they handle local conditions as they multiply to an expected 300,000 before being released into the wild to start their relentless killing spree.

It's unclear how much damage mealybugs have caused to Indonesian crops, but infestations have been reported on the main cassava-growing island of Java and in parts of Sumatra, according to Kris Wyckhuys, an entomologist at the International Center for Tropical Agriculture in Colombia, which is helping to coordinate the wasps' release.

Preemptive strike

He said the idea is to introduce the wasps early because the mealybugs, if left unchecked, can destroy more than 80 percent of a harvest. They suck the cassava's sap until the plant withers and dies.

Indonesia is one of the world's top producers of cassava, planting around 1 million hectares annually, half of which is eaten as a staple food across the sprawling archipelago of 240 million people.

The long roots of the shrub-like plant are a major source of carbohydrate and provide an array of nutrients. Like the potato, cassava is a versatile starch that's an essential part of daily meals across much of the developing world. In Indonesia it is boiled, fried and made into noodles, crackers and even cakes.

Known elsewhere as manioc, tapioca and yucca, it is also made into livestock feed and used as an ingredient in a variety of products worldwide, ranging from lipstick and artificial sweeteners to paint and glucose IV drips.

(China Daily 09/25/2014 page11)