As the temperature gradually rises, garden plants enter the golden age of growth, and garden leaf-eating pests also occur. Leaf-eating pests are very numerous, large in number and explosive, and can cause plant death when the damage is serious.
Boxwood silk borer is a genus of lepidoptera borers, is one of the leaf-eating pests on hedge plants such as large-leaf boxwood and small-leaved boxwood. It mainly harms the top and leaves of the plant
Hazard characteristics
Adult boxwood silkworms have phototropism, poor flight ability, day and night, often roost in the shade during the day.
After the larvae hatch, they disperse to look for young leaves for feeding, and the young larvae feed on the leaf epidermis and leaf flesh. Before the 2nd instar, the larvae eat less, and after 3 years of age, the feeding range expands, the harm is aggravated, and it is binge eating.
Larvae over 3 instar eat the leaves, and spit silk conjugate the leaves, feed in them, when the occurrence is severe, the amount of insects per plant can reach 100, and the leaves of the affected plants can be eaten in just a few days, and photosynthesis cannot be carried out.
Regularity of occurrence
Boxwood silkworm can occur 3-4 generations a year, the generation overlap is serious, with 3-4 year old larvae in the conjugated leaf buds as a cocoon overwintering, the following year from late March to early April began to bud hazards, and pupa feathering.
Due to the temperature differences in each region, the occurrence period of the boxwood silkworm borer is slightly different. If the temperature is high in early spring, the hazard of overwintering generation can be about 15 days in advance. (Larval infestation period in some areas, for reference)
Hebei region: the first generation of larvae occurs from mid-May to late July, the second generation occurs from late July to early September, and the third generation occurs from mid-September to late October.
Hubei region: the first generation occurs from late April to early June, the second generation occurs from early to mid-June to late July, and the third generation occurs from early August to mid-to-late September.
Henan region: May to June is the first generation occurrence period, July to late August is the second generation occurrence period, September to October is the third generation occurrence period.
Integrated prevention and control techniques
Boxwood silkworm is a garden pest that specifically harms boxwood plants, with the characteristics of early onset, generational change, and long onset time. Therefore, its prevention and control should be based on the principle of "prevention first, scientific prevention and control, and comprehensive management" and actively do a good job in prevention and control.
1. Strengthen care management
The occurrence of insect pests is closely related to the growth of boxwood, for poor growth should be reasonable fertilization, soil loosening, weeding, high temperature and drought season should pay attention to drought resistance, rainy season to timely drainage, keep the tree strong, improve the resistance of boxwood itself.
When planting plants, it is necessary to reasonably control the planting density and maintain a ventilated and transparent environment, which can greatly reduce the occurrence and occurrence of pests and diseases.
2. Physical prevention and control
(1) Do a good job in clearing the garden in winter: remove dead branches and leaves and weeds, and destroy the eggs of overwintering insects in a concentrated manner, which can effectively reduce the source of insects in the second year.
(2) Protection and utilization of natural enemies: biological control and physical control are carried out to protect and utilize natural natural enemies such as parasitic jumping wasps, ants, concave-eyed wasps and parasitic flies, or artificial breeding, and release in the concentrated area, which can effectively control the harm caused by them.
3. Chemical control
Pharmaceutical prevention and control is an important measure to control the yellow poplar silk borer, timely and rational use of drugs, as far as possible to achieve "early treatment, treatment of small, cure". The key stages of drug control are the budding stage of overwintering larvae and the young age stage of the first generation of larvae, because the insect resistance is weak and the insect population density is small.
It is recommended to use "Shenrun Lindan No. 1" with water 150kg-250kg during the nymph period, focusing on spraying pest damage sites; or use "Shenrun Lake" to mix water with 200kg-250kg for uniform spraying.