More than 20,000 hectares of farmland and forest in east China's Shandong Province were damaged by the fall webworm moth in 2006, three times the area that was ravaged the previous year, the provincial forestry bureau reported on Tuesday.

Before 2004, the insect was only found in farmland and forest in Dongying, Yantai and Weihai cities, however its territory extended sharply within last two years to four neighboring cities: Qingdao, Binzhou, Weifang and Zibo, said Li Zhanpeng, director of the bureau's wildlife and forest protection department.

Experts attributed the spread of the moth's influence to increased agricultural trade between the cities, raising the possibility of cross infection.

The moth, dubbed "the leaf killer", can defoliate over 300 kinds of leafy plants and trees, such as crops, willow, elm and poplar.

Besides Shandong, last year, the moth plagued a vast area in north China, including Beijing, Tianjin, Hebei and Liaoning, affecting 234,000 hectares of farmland and forest.

According to agricultural experts, the moth is expected to plague more areas of north China this year as abnormally warm weather has helped more of the insects survive the winter.

Currently, Shandong, Beijing, Tianjin, Hebei and Liaoning have taken joint efforts to curb the spread of the moth-plague, involving an investment of 22.5 million yuan (US$2.87 million), Li said.

"We will take a series of anti-moth measures to protect farmland and forest," he said, adding that the efforts included breeding the moth's natural enemy - two billion silkworm parasites will be bred in 2007 - and using stronger pesticides.

(Xinhua News Agency March 21, 2007)