Scientific name Lacoptera quadrimaculata quadrimaculata (Thunberg) Coleoptera, Tetrigidae. Alias ​​sweet potato brown tortoiseshell, sweet potato large tortoiseshell. The distribution ranges from Jiangsu, Henan, and Gansu in the north, to Taiwan, Hainan, Guangdong, Guangxi, and Yunnan in the south, to the coast in the east, and to Sichuan and Tibet in the west.
Host sweetpotato and other Convolvulaceae plants.
Injury characteristics, larvae eat leaves into a short cut or hole, the edge of food along the side of the excrement, insects, mouthfuls of potato leaf perforation, affecting growth.
Morphological characteristics female adult body length 9.5mm, shoulder width of about 8.1mm; male body length 9mm, shoulder width 7.3mm, all tea brown. There are many curved longitudinal ridges on the pronotum. A dark spot was created near the edge of the elytra, extending toward the middle of the panel toward the open side. There are also 1 dark spots on the back corners and the seam angles, and there are generally no dark spots on the shoulder tumors. There are a lot of small engraved spots on the elytra, and the camel's top is very protuberant. Females are coarser than males and have a reticular pattern on the pronotum and esophagus. Tentacles are brownish, 9-11 black. Egg length 1.5mm, width 0.5-0.7mm, oval, brown, both ends of the thin. The last-instar larvae have a body length of 7.5–8 mm, dark brown, and 8 yellow-brown branches on each side of the abdomen. In the front of the prosthodontic plate, a pair of semi-circular irregularly concave eye-spots were placed. The tail was rolled up on the back and lifted on the tail. The body is light yellow-brown. Pronotum flat, with hard thorns around the perimeter.
Living habits 6 generations in Guangdong, Fujian 4-6 generations, overlapping generations. Adults wed over weeds, earth seams or overwintering stems. In the middle of March of the following year in Guangdong, adults emerged. Adults in Fujian started in mid-May. Adults in mid-September were prosperous, and the insects prospered in high-temperature and drought conditions. The scope of larvae activity is not large, many holes occur in potato leaves, affecting the growth and development of sweet potato. The worm is in Taiwan, the egg period is 10 days, the larval period is 20 days, and the pupa period is 10 days. Adult eggs are produced on the leaves.
Control methods (1) The sweet potato can be cleaned in a timely manner after harvesting and the weeds in the field can eliminate some of the overwhelming insect sources. (2) At the time of adult emergence, sprayed with 1200-fold diluted crystals of trichlorfon, or 1500-fold with 40% dimethoate, 1000-fold with 50% fenthion EC, and 800-fold with 25% imidothiophosphate in the evening. Liquid, 50% chlorpyrifos EC 900 times, sprayed 75L per 667m2.
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