{"id":26567,"date":"2026-10-01T16:27:49","date_gmt":"2026-10-01T10:42:49","guid":{"rendered":"https:\/\/eng.dragonmedia.com.np\/?p=26567"},"modified":"2026-10-01T16:27:49","modified_gmt":"2026-10-01T10:42:49","slug":"beijing-releases-another-400-million-parasitic-wasps-to-control-invasive-pest","status":"publish","type":"post","link":"https:\/\/eng.dragonmedia.com.np\/?p=26567","title":{"rendered":"Beijing Releases Another 400 Million Parasitic Wasps to Control Invasive Pest<\/strong>"},"content":{"rendered":"

Dragon Media News Desk<\/strong><\/p>\n

Beijing has begun releasing another 400 million parasitic wasps to curb a growing infestation of fall webworms, an invasive pest that damages trees and crops. The biological control campaign began on Monday, Xinhua reported.<\/p>\n

Yang Zhongqi, chief scientist at the Chinese Academy of Forestry and discoverer of the wasp, said nearly 700 million had already been released earlier this year. Scientifically known as Chouioia cunea Yang, the wasps are major natural enemies of the pest and are safe for humans and livestock, he said.<\/p>\n

Native to North America, the fall webworm can damage more than 300 plant species. In Beijing, over 200 species of trees, fruit trees, flowers and crops are at risk. Yang said that although the insect damages vegetation, neither its larvae nor adults are toxic or harmful to humans.<\/p>\n

Beijing is currently experiencing the peak damage period of third-generation larvae. Mature larvae are expected to descend from trees to pupate, making this a key stage for targeted control. The pest produces three generations annually, each passing through egg, larval, pupal and adult stages.<\/p>\n

Yang Sihan of Beijing\u2019s municipal landscape and greenery resource protection centre attributed this year\u2019s increase mainly to warmer winters and frequent summer rainfall. Surveys in some areas showed that the survival rate of overwintering pupae rose from 65.3 percent in 2023 to 84.2 percent this year. Rainfall also disrupted control operations.<\/p>\n

The pest\u2019s strong reproductive capacity makes containment difficult. A female moth typically lays 300 to 600 eggs and can produce up to 2,000 under favourable conditions. Different generations and life stages have also overlapped this year. Narrow urban spaces, tall trees with dense canopies and the limited reach of ground sprayers present additional challenges.<\/p>\n

Authorities have established nearly 3,000 monitoring sites across the city. Pest patterns, weather data and expert consultations inform rolling long-, medium- and short-term warnings. Alongside biological control, crews remove larval webs and wrap tree trunks with corrugated paper and non-woven fabric to trap descending larvae.<\/p>\n

Traps and insect-killing lamps are used against adult moths. Authorities are also applying efficient, low-toxicity, environmentally friendly pesticides, with ground spraying conducted at staggered times. The Beijing Municipal Forestry and Parks Bureau has urged residents to remove dead branches, fallen leaves and clutter, and to cut off infested branches and leaves and dispose of them in sealed bags.<\/p>\n

Residents who notice chewed leaves, webs or mature larvae on trees in public areas can report them through the 12345 citizen hotline or their local landscaping and greening department.<\/p>\n

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