Sweet potato moth

Classification: Pests

Pesticides for prevention and control: Dichloraz, dimethoate, imidophos, and betamethasone

Applied crops: Potato and taro crops - Sweet potato yam

Sweet potato moth

The scientific name is Brachmia macroscopa Meyrick, belonging to the Lepidoptera order and the family Lycaenidae. Distributed in North China, East China, Central China, South China, and Southwest.

Host plants such as yam, sweet potato, and water spinach in the family Convolvulaceae.

Harmful characteristics: The larvae gnaw on new leaves and form a network of young buds. The larvae burrow into the buds, and when the insect grows, they gnaw on the leaf flesh, leaving only the epidermis, causing the damaged part to turn white and then brown and wither. When severe, only leaf veins remain. When you grow up, roll up the leaves and bite them into holes. Morphological features: The adult insect has a body length of about 4mm, a wingspan of 18mm, a wingwidth of 2.5mm, and a black brown body. The head and face are tightly covered with dark brown scales. The front wings have dark brown mixed with grayish yellow scales, and the wings and veins are green. There are white stripes near the center, with 5 horizontal black spots on the outer edge, and the back wings are dark grayish white; The larva has a body length of about 6mm, with a light yellow head and a light yellow green body, indicating a dark purple color inside.

Living habits: 3-4 generations are born in North China and Zhejiang, 5-7 generations are born in Jiangxi and Hunan, and 8-9 generations are born in Fujian and Guangdong. They overwinter by cocooning their pupae in the leaves. The following year, when new yam sprouts, it harms, with the highest occurrence occurring from July to August. Place the egg near the rib of the tender leaf.

The prevention and control methods should be combined with the prevention and control of Dioscorea scabra for comprehensive treatment. When necessary, spray 90% crystal trichlorfon 80C-1000 times solution or 40% dimethoate emulsion 1000 times solution, 50% imidophos 500-800 times solution, and 50% phoxim emulsion 100C times solution at the initial stage of larvae. Spray 75L of the appropriate solution every 667m 2.