Control of soybean leaf borer, Chilo suppressalis

Soybean leaf borer is the main pest in soybean production in summer and autumn, which not only harms soybean, but also harms mung bean, peanut and other leguminous plants. In recent years, with the increase of winter temperature, the number of overwintering insects increased, which increased year by year in soybean fields. At present, it is the harmful period of soybean leaf borer, so the control should be carried out in time.

Soybean leaf borer harms soybean leaves with its larvae. Before the 3rd instar, it likes to eat mesophyll but not curl leaves. After 3rd instar, it begins to roll leaves. The 4th instar larvae roll bean leaves into a tube, lurking in them, sometimes several leaves are rolled together, often causing flowers and pods to fall. The adults lie dormant at day and night, have phototaxis and like to be active in the evening. The eggs are scattered on the back of soybean leaves, and the larvae pupate in rolled leaves after maturity.

According to relevant data, the soybean leaf roller entered the peak period of first-generation larvae from mid-July to early August, and the damage was the most serious from late July to early August, and the plant rate of rolled leaves in the field increased significantly, and the plant rate of serious leaf curling in the field reached more than 90%. It entered the peak period of pupation in mid-late August, the occurrence period of the first generation adults from late August to early September, and the peak period of damage to the second generation larvae in September. The rainy and humid climate is beneficial to the occurrence of soybean leaf borer, and the soybean fields with dense growth, late-maturing varieties and varieties with few leaf hairs suffer more seriously when applying too much nitrogen fertilizer or late sowing fields.

Chemical control is currently an important means of prevention and control of soybean leaf borer, which should be started at the beginning of egg hatching (it is found that 1% of 2% of plants in the field have leaf roll harm), once every 7-10 days, twice in a row. The available agents are cyhalothrin, cypermethrin, fenvalerate, chlorpyrifos, indenyl, fipronil, hydrazine fenvalerate, avermectin and so on.