How to control the cupreous chafer? Master its occurrence patterns and key control points

The cupreous chafer beetle belongs to the order Coleoptera, family Scarabaeidae. It occurs in many apple orchards in our region, and its hosts include apple, hawthorn, crabapple, pear, apricot, peach, plum, Japanese apricot, persimmon, walnut, strawberry, and so on.

I. Damage symptoms

Apple trees suffer the most severe damage from the cupreous chafer beetle; the adults feed on leaves, often causing large areas of young fruit trees to have incomplete leaves, and even entire trees stripped of all leaves.

II. Occurrence patterns

(I) The cupreous chafer beetle has 1 generation per year, overwintering as mature larvae in the soil.

(II) In the following spring, before the larvae pupate, they damage the roots of crops and weeds. In Zhaoyang District, they emerge as adults in mid to late May, and the adults begin to come out of the soil in early June. The period of severe damage is concentrated from June to early July, and after mid-July the number of insects gradually decreases. The main damage period is about 40 days.

(III) The adults hide by day and come out at night. They begin to emerge after sunset, first mate, then feed, and before dawn they burrow back into the soil, mostly hiding in the upper surface layer 3-6 cm deep, and they prefer to inhabit loose, moist soil.

(IV) The adults have a death-feigning habit and strong phototaxis; large numbers are attracted to lights, and more females than males come to the lights. About 10 days after emergence they begin to lay eggs. The eggs are laid in the soil, mostly at a depth of 3-10 cm. The larvae mainly feed on plant roots, and when they develop to maturity they overwinter directly in the soil.

III. Control methods

(I) Chemical control

1. During the adult occurrence period, spray the tree canopy with 50% fenitrothion (sumithion) emulsifiable concentrate at 1500 times dilution, or 50% parathion emulsifiable concentrate at 1500 times dilution.

2. Spraying Bordeaux mixture with excess lime has a certain repellent effect on adults, and pesticide can also be applied to the surface soil layer.

3. Apply 75% phoxim emulsifiable concentrate at 1000 times dilution in the tree basin or in the weeds at the orchard edge, then shallowly hoe it into the soil, which can kill large numbers of adults lurking in the soil.

(II) Manual control: Taking advantage of the adults' death-feigning habit, shake them down in the morning and evening and kill them.

(III) Trapping and killing adults: Taking advantage of the adults' phototaxis, when adults occur in large numbers, light fires at the edge of the orchard after dusk to attract and kill them. Orchards with the conditions can use black light lamps to trap and kill large numbers of adults.