During the cultivation of sorghum, farmers often encounter various pests and diseases, which cause great losses to farmers. Therefore, farmers should take measures to prevent and control it. This article summarizes the symptoms, occurrence rules, morphological characteristics and prevention and control measures of sorghum borer, hoping to help farmers.
Symptoms of harm:
Larval moth stems are infested.
Occurrence rules:
2 to 3 generations occur every year on the Yunnan-Guizhou Plateau, 3 to 4 generations occur in Jiangsu and Zhejiang every year, 4 generations occur in Jiangxi, Hunan, Hubei and Sichuan every year, 4 to 5 generations occur in Fujian, Guangxi and Kaiyuan in Yunnan, and 6 to 8 generations occur every year in southern Guangdong and Taiwan. In the northern region, some larvae are found in rice piles and others.
Morphological characteristics:
(1) Adult worms. Adults are 12 to 15 mm long, with a wingspan of 27 to 30 mm, and the female is larger. The cephalothorax is grey-black, the abdomen is pale brown, the forewings are nearly rectangular, pale greyish brown, the outer edge is dark, and there is a dark brown longitudinal line from the base of the wing to the outer edge, with two small black dots above and below the stripe. The male moths have ctenophoric antennae and the female moths are filamentous.
(2) Larvae. The larvae are generally 5 years old, and a few are 6 to 7 years old. The back of the 3-year-old forebreast is bright yellow, and the 3-year-old is purple-red. The toe hook sequence is arranged in a half-ring on the inside.
(3) Eggs. The eggs are oblate spherical, slightly concave at the top, 0.5 mm in diameter and about 0.3 mm in height, with radial thin ridges on the surface. It is white at first birth, then pale yellow, then reddish, and grayish brown before oviviparation. The eggs are on the inner side of the leaf sheath, arranged in bands in 2 to 3 rows or scattered.
(4) Pupae. Male pupae are 13 to 14 mm long and female pupae are 15 to 18 mm long. It is pale yellow at first, then yellowish brown, darker on the back, and has a white powdery discharge on the cephalothorax. Except for the near posterior margin of the 2 to 7 abdominal segments, there are small black-brown rounded incisions, the base of the gluteal is obviously black, and there are 2 small protrusions on the back and ventral surface.
Prevention and control measures:
(1) Agricultural control. During winter and spring, fieldside weeds are eradicated to eradicate overwintering larvae and pupae. Before the eggs hatch, remove barnyard and fieldside weeds. Remove the remains of the plant in time after harvest and eliminate the larvae and pupae. In areas with large white leaves, the white leaves are the main source of overwintering insects, and the residue should be cut off in the mud before early spring.
(2) Pharmaceutical prevention and control. When the sheath rate of dry sheath reaches 5% in production or when the dead heart seedlings are first seen as harmful, most of the larvae are in the 1 to 2 years of age, and timely spray control. Spray once every 5 to 7 days, generally 2 to 3 times can be prevented. The agent can choose 40% imidacloprid wettable powder 500 times liquid, or 55% special borer wettable powder 1000 times liquid, or 50% insecticidal double soluble powder 1000 times liquid, or 20% strong borer-free emulsion 1500 times liquid, or 25% good winter emulsion 3000 times liquid, or 20% triazolpyridine emulsion 700 times liquid.