What are the control methods for the fall webworm?

Bundle grass around the tree trunk; after the larvae pupate inside the grass bundle, remove the bundle and burn it in a centralised manner. Contact and stomach poisons can also be used, such as 80% dichlorvos emulsifiable concentrate at 1000 times dilution, 2.5% deltamethrin emulsifiable concentrate at 2500 times dilution, and 4.5% beta-cypermethrin emulsifiable concentrate at 2300 times dilution for three-dimensional, comprehensive and meticulous spraying control.

1. Physical control methods

Taking advantage of the larvae's habit of descending the tree to pupate, grass can be bundled around the tree trunk; after the larvae pupate inside the grass bundle, remove the bundle and burn it in a centralised manner.

Manual pruning and removal: in mid to late May, adults begin to lay eggs; organise workers to search for egg masses on the leaves, remove and destroy them. From late May to early June, 1st to 3rd instar larvae spin webs and gather in the canopy to cause damage, and the leaves of the affected plants take on a white membranous appearance and turn yellow and withered, with only the leaf veins remaining in severe cases; after the 4th instar they disperse to feed and enter a gluttonous stage. Every 2-3 days, carefully search once for the web tents of fall webworm larvae; once a web tent is found, use long-reach pruners to cut off the web tent together with the small branches and destroy them.

2. Chemical control methods

During the period when larvae are causing damage, achieve early detection and early control. Mainly use contact and stomach poisons, such as 80% dichlorvos emulsifiable concentrate at 1000 times dilution, 2.5% deltamethrin emulsifiable concentrate at 2500 times dilution, and 4.5% beta-cypermethrin emulsifiable concentrate at 2300 times dilution for three-dimensional, comprehensive and meticulous spraying control.