LANG SON (VNS) — A pest called Oides leucomeleana Pic has devastated thousands of hectares of star anise trees in northern mountainous Lang Son Province in the last four years.
The provincial Plant Protection Department said it lacked effective measures to kill the pests. As a result, more than 1,300 hectares of trees were destroyed.
Star anise is one of the province's key agricultural export products. There are more than 33,000 hectares of trees, resulting in annual turnover of VND600-700 billion (US$28.5 million-33.3 million).
The pest first appeared in Van Quan and Cao Loc districts, where 250-350 pests living in each tree have destroyed 900 hectares of star anise.
Lang Van Nhat, a resident of Van Quan District's Lung Cung Commune, was able to harvest four tonnes of star anise from his 320 trees before the pests came. Now the garden is seriously damaged and many trees have only bare branches.
Nhat said the pests only came out at night and were hard to detect, as they built their nests on the wet ground but climbed up trees when they grew up.
About 100 pests could devour all the flowers and leaves on a tree in one night, he said.
Head of the provincial department Hoang Van Day said that the department had tried many different methods to prevent the pests from spreading, with little success.
Since February, the department had guided district plant protection stations to spray two tonnes of chemicals and more than ten tonnes of additional powder on star anise gardens to exterminate the bug. However, these chemicals were only effective in cold weather.
The department also used another kind of chemical on 300 hectares of trees in Van Quan District. After four days, the number of bugs in each tree decreased by 50 to 100.
The department recommends that farmers continue spraying the chemicals every one or two weeks. — VNS