What is the box tree pyralid, an insect found beside vegetable fields?

As spring warms and flowers bloom, insects begin to become active. During a recent science-and-technology outreach activity in the countryside, it was found that a pest called the box tree pyralid had begun to occur and cause damage on boxwood along the roadsides of the park.

The box tree pyralid is one of the common pests on plants such as boxwood, small-leaved box, large-leaved box, littleleaf box, Chinese box, spoonleaf box, Korean box, and holly, and it occurs in Shanghai and other provinces and cities. In Shanghai it has 3 to 4 generations per year, with severe overlapping of generations. It usually becomes active in March in spring, begins pupating in mid-April, begins emerging in late April, the first-generation larvae appear in early May, the first generation begins pupating in early June, the first-generation adults emerge in mid-June, eggs are laid in late June, and at the same time the second-generation larvae begin to appear, pupating in mid-July, with second-generation adults appearing in late July; eggs are laid in early August, and at the same time third-generation larvae appear, pupating in mid-August, third-generation adults begin emerging in late August, eggs are laid in early September, overwintering-generation larvae appear in mid-September, and they enter the overwintering period in mid-October. Larvae in the 1st to 2nd instars feed on the leaf mesophyll, and after the 3rd instar they spin silk to make a nest and feed inside it. Damaged leaves first show yellow dead spots, and later the entire leaf falls off. They spin silk to bind the leaves and the damaged fallen leaves together, so that the leaves cannot unfold and growth and development are severely affected; when the damage is severe, the entire plant dies. Adults hide during the day and are active in the evening; their flight ability is weak and their phototaxis is not strong.

To control this insect, management should be strengthened in cultivation to promote robust growth and increase its ability to resist pests and diseases. Reasonable pruning and manual capture can remove part of the insect source and improve the ventilation and light penetration of its growing environment. Chemical control should be carried out when necessary. During the period from larval hatching to damage by the 2nd instar, spray 20% diflubenzuron at 800-1000 times, 20% Lüan at 1000-2000 times solution, and 4.5% beta-cypermethrin at 1500 times solution.