Beijing releases parasitic wasps and runs caterpillar hunts against fall webworm

Centre · 1Authorities in Beijing are releasing parasitic wasps and encouraging caterpillar-catching competitions to contain the spread of the invasive North American fall webworm, whose caterpillars have blanketed trees in Beijing and surrounding areas this summer. 1 Centre · 1According to a China Science Daily report, Beijing has released 1.1 billion Chouioia cunea, a parasitic wasp discovered in the 1980s that is a natural predator of the pest. 1 Centre · 1Municipal workers have also removed webs, trapped moths and sprayed pesticides, and nearly 3,000 monitoring sites have been set up around Beijing, Xinhua reported. 1

Centre · 1Beijing Wildlife Park, which calls the pest "the forest food monster", has asked visitors over the Golden Week holiday to catch as many caterpillars as possible, with prizes of up to 10 park tickets for the heaviest hauls. 2 Centre · 1Since the contest began on 28 September, about 2,077 people have caught more than 310,000 caterpillars weighing 47.65kg in total, CNA reported. 2 Centre · 1Chen Min, a professor at Beijing Forestry University, wrote that a warm winter and rainy summer created ideal conditions for the pest, with wet weather washing away pesticides, and that this generation has a greater risk of spread than usual. 1

Centre · 2The pest is harmless to humans but threatens hundreds of plant species; CNA puts the figure at more than 300, including crops and fruit trees, while SCMP names street trees such as mulberry, ash and plane. 1 2 Centre · 2The insect produces three generations a year, and Beijing is now seeing peak damage from the third, though Xinhua said the first generation, emerging around May, is the most important to target. 2 1 Centre · 1The pest was first found in China in 1979 and is now present in 13 provincial-level areas; Chen said this year's outbreak exposed gaps in control efforts, which need better synchronisation as climate change expands suitable habitat. 1