Leaf wasps are an insect pest that occurs during the growth of yam, usually biting the yam leaves, resulting in a serious loss of leaves, resulting in a decline in yam yield and affecting the planting efficiency of farmers. This article summarizes the harmful symptoms, living habits and control methods of yam leaf wasps, hoping to help farmers better cope with the pest.
Hazard Symptoms:
Yam leaf bees incubate the larvae for 3-5 minutes after feeding on the leaves near the egg mass; at 1-2 years old, they only eat the leaf flesh, leaving the epidermis, causing transparent spots, often 20 or 30 head clusters are harmed; after 2 years of age, they are scattered on the back of the leaves, and eat from the leaf tip to the petiole, and the 4-5 years old is the overeating stage.
Life Habits:
North China and East China are born in two generations per year, using larvae as cocoons in the soil to overwinter, pupating in April of the following year, and feathering into adult insects in May and June. Adults are active during the sunny day, flying to nectar and aphids to feed on nectar, often pricking longitudinal lobes in new shoots and laying eggs. The hatching larvae cluster on the leaves, eat the leaves, and in severe cases eat the leaves, leaving only the veins or petioles. The first generation of adults feathered and laid eggs in July to August, entered the peak period of the second generation of larvae in mid-to-late August, and overwintered in october.
Prevention and control methods:
(1) Collect dead leaves in autumn and winter and burn them intensively, and plough in winter to eliminate overwintering larvae.
(2) Pharmaceutical control: Apply medicine to control in the early stage of larval occurrence, and the application time is best at 4-5 pm. Agents can choose 2% Tianda avermectin emulsion 1500 times liquid, 20% Tianda acetylhydrazide suspension 2000 times liquid, 48% Lesben emulsion or 48% Tianda Chlorpyrifos 1000 times liquid, 20% insecticide urea suspension 1500 times liquid, 5% cardiac dispersible liquid 1500 times liquid, 10% exhaust suspension 2000 times liquid, B.T. emulsion (10 billion spores/ml) 400 times liquid, 52.25% agrodistic emulsion 1500 times liquid, 20% 3000 times solution of permethrin emulsion, 2.5% cypermethrin emulsion 2500 times liquid, etc., stop the medication 10 days before harvest.