Occurrence Patterns and Control Methods of the Potato Tuber Moth
The potato tuber moth, also known as the potato borer and the tobacco leafminer, is commonly called the "string-skin worm," "embroidery worm," and "potato maggot" by farmers.
1. Damage symptoms
The larvae cause damage mainly by boring and feeding, usually entering through the buds and broken skin of the tubers. Larvae hatched on the plant spin silk and spread with the wind, boring from the leaf surface into the leaf interior to feed and cause damage. After the damaged leaves wither and die, the larvae move to other leaves to cause damage.
2. Occurrence patterns
The potato tuber moth produces several generations a year, overwintering in various stages on mother tubers in the field and on the residual plants and fallen leaves of various hosts. Adults hide by day and come out at night, are phototactic, and are not strong fliers. Female moths lay eggs on the buds, broken skin, cracks, and soil-covered parts of the tubers, with the most eggs laid at the buds. This insect can tolerate relatively low temperatures; adults can still survive at minus 7°C. Outbreaks are mild in flood years and severe in drought years. Outbreaks are severe when planting is shallow and hilling is thin, and mild when planting is deep and hilling is thick.
3. Control methods
1. Seed tuber fumigation treatment: Use 12 tablets of aluminum phosphide or cricket medicine, divide into three portions, wrap each tightly in toilet paper, and place them evenly among 1000 kg of tubers. Cover tightly with plastic film without air leaks. When the temperature is 12-15°C, fumigate for 5 days; when above 20°C, keep sealed for 3 days. Note: do not fumigate in places where people live, to avoid poisoning. The waste residue after use is toxic and must be buried deep.
2. Control during storage: Before storage, carefully clean the storage room and close doors and windows tightly to prevent tuber moths from flying in to lay eggs. If tuber moths are found, use deltamethrin, dichlorvos, and similar insecticides to kill the flying moths.
3. Field control: Strictly select insect-free seeds when sowing. When transparent spots caused by larval damage are found on leaves in the field, remove the leaves and take them out of the field to bury deep or burn. Carry out intertillage and hilling well to prevent tubers from being exposed. During the peak moth emergence period, promptly spray pesticides such as deltamethrin and dichlorvos to kill the flying moths.