Angoumois grain moth

Scientific name Sitotroga cerealella (Olivier), belonging to Lepidoptera, family Gelechiidae. Distributed throughout the country.

Hosts @#@245@#@, corn, rice, sorghum, buckwheat, seeds of gramineous weeds, edible fungi, etc.

Damage characteristics: larvae bore into and feed on the above seeds.

Morphological characteristics: adult body length 4-5mm, wingspan 14-18mm, body grayish yellow; compound eyes black, antennae filiform, grayish brown; top of head and face densely covered with grayish brown scales; labial palps grayish brown, the second segment relatively thick, the third segment tapering to a fine point at the tip, slightly curved upward, not exceeding the top of the head; forewings grayish white, resembling bamboo leaves in shape, usually with indistinct dark brown markings, hind margin fringes long, brown; hindwings grayish white, trapezoidal, outer margin concave, apex pointed and protruding, hind margin fringes very long, equal to the wing width. Egg flattened oval, length 0.5-0.6mm, one end slightly flattened and truncated, surface with longitudinal and transverse ridges, milky white to light red. Larva body length 5-8mm, newly hatched light red, becoming pale yellowish white after the 2nd instar, milky white when mature, head small; thorax relatively swollen, tapering gradually toward the rear, each segment slightly wrinkled, thoracic legs very small; abdominal prolegs degenerated, each proleg bearing 1-3 tiny brown crochets at the tip. Pupa length 4-6mm, yellowish brown, relatively slender.

Life habits: 4-6 generations per year in the south, 2-3 generations in the north, up to 12 generations in regions with high temperatures. Overwinters as mature larvae inside grain kernels. Before pupation, it spins a thin white cocoon. Pupal stage lasts 5 days. When the adult emerges, it pushes through the thin membrane and bores out of the grain kernel. Adults prefer to emerge in the early morning, mate immediately after emergence, adult lifespan about 13 days. Oviposition occurs 24 hours after mating. Eggs are mostly laid at a depth of 20cm in the surface layer of grain piles, with the most at 7cm. Some adults fly to the field and lay eggs on corn kernels, wheat heads, and rice heads. Eggs are mostly laid in clusters, with each female laying 389 eggs. Generally 1 larva per grain, 2-3 on corn, and up to 10-20 eggs. Larvae can move between grains to cause damage. Develops rapidly at 21-35°C.

Control methods: (1) For storage warehouses of cereal crops, prevention and control should be carried out well to prevent Angoumois grain moths from migrating into wheat fields or grain fields. Sun-dry before storing in warehouses. Before storage, spread the grain to a thickness of 3-5cm so that the sun-drying temperature reaches 45°C and maintain for 6 hours, which can kill the eggs, larvae, and pupae of the Angoumois grain moth in the grain. (2) After storage, at a ratio of one tablet of aluminum phosphide per 150-200kg of grain for fumigation, scatter and bury aluminum phosphide tablets in the grain stack, then seal the grain stack tightly. When there is a large amount of stored grain in the warehouse, apply 4-5 tablets per sq m of grain stack and space, placing several tablets at each spot buried 50cm below the grain surface and around the perimeter of the granary. After application, seal tightly. At a temperature of 20°C, seal and fumigate for 3-4 days. (3) Field control, mainly targeting eggs and newly hatched larvae, eliminating them before they bore into the grain. Specific method: during the local peak oviposition period to peak egg hatching period of the Angoumois grain moth, when there are 2 or more eggs per wheat head, spray 50% phoxim emulsifiable concentrate or 40% omethoate emulsifiable concentrate 75ml or 20% fenvalerate emulsifiable concentrate 30ml per 667 sq m, mixed with 50kg water for spraying or mixed with 20kg water using a mist sprayer for misting, with obvious effectiveness.