AS HUNDREDS of thousands of parasitic wasps – Apoanagyrus lopezi – spread throughout the Thai countryside, officials said yesterday that they were unsure when Cambodia would receive its own shipment, which would be used to combat a mealybug infestation that is threatening cassava crops.
The government approved the use of the wasp last month after receiving a request in April from an NGO that works with cassava farmers in the northwest. Hean Vanhan, the deputy director of the Agriculture Department at the Ministry of Agriculture, Forestry and Fisheries, said on June 28 that the wasps were expected to arrive early this month.
Yesterday, however, he said he was not sure when the wasps would arrive, and that funding for them had not been allocated by his ministry. He added that the Ministry of Economy and Finance would need to sign off on the transaction after that. He could not say when these steps might be taken.
He said there had been no response to a funding proposal submitted to the Ministry of Economy and Finance.
“We made a proposal of funds, but we don’t have the funds yet,” he said. Finance officials could not be reached yesterday.
A total of 250,000 wasps were released into the northeastern Thai province of Khon Kaen over the weekend, according to the International Centre for Tropical Agriculture. The presence of mealybugs in Thailand is one factor expected to reduce cassava yields for 2009-10 to 23 million tonnes, down from an earlier projection of 29 million tonnes.
The Bangkok Post reported in February that private-sector analysts had predicted that the yield could drop to as low as 20 million tonnes, a decline that could translate into the loss of hundreds of millions of dollars.
“Sending in the wasps is a proven way to kill the cassava mealybugs quickly and effectively,” said Tony Bellotti, an ICTA entomologist. “Think of them as a kind of eco-friendly SWAT team.”
The wasp is said to have already shown itself to be a formidable natural enemy of the cassava mealybug in South America and sub-Saharan Africa, helping protect the industry by killing its unsuspecting host from the inside out. The wasps inject their eggs into the mealybugs, and when the eggs hatch, the larvae kill the host. Adult female wasps also feed on the mealybugs.
Hean Vanhan said implementation of the wasp scheme would likely require help from Thailand. “We need technical support from Thailand,” he said. “Biological control is not a procedure that we’ve tried before. We need to know the method to breed.”
John Macgregor, communications director for the NGO Cambodian War Amputees Rehabilitation Society, which sought government approval to import the wasps, said yesterday that Thailand had agreed to supply the wasps, but that recent attempts to contact officials there had been unsuccessful.
“We are awaiting the Thais’ response to our request to visit and pick up some wasps for here,” he said. “But I gather they have been busy with their own release, so no response yet.” Dr Amporn Winotai, the Thai entomologist said to be supplying the wasps, could not be reached for comment.
Heng Bunhor, director of the Banteay Meanchey provincial Agriculture Department, estimated that 8,000 of 35,000 hectares of cassava in the province had been destroyed by mealybugs.
ADDITIONAL REPORTING BY AFP