Recently, users from Guilin City sent pictures of citrus problems, asking: The bark has been eaten, what medicine can be used to prevent it?
Experts give answers based on the pictures displayed:
Mao Weishan (Dali, Yunnan Province, specializing in citrus, grapes, dates)
Tianniu larvae are controlled with octyl thiophos, avermectin, and permethrin.
Feng Tao (Lu'an City, Anhui Province, Agricultural Technology Station)
Tianniu larval hazards Use bifenthrin + lydyridine to inject insects in the hole.
Lv Lanhua (Liaocheng City, Shandong Province, good at plant protection technology)
Mid-day larvae. High-efficiency cypermethrin irrigation control is optional.
Guo Xinhua (Agronomist, Technical Station Manager, Guan County, Liaocheng City, Shandong Province)
Tianniu larvae harm, with a needle tube into the borer infusion bifenthrin, octylthion, cypermethrin, chlorpyrifos, chlorpyrifos, dichlorvos, etc., with mud to seal the borer hole can be.
Big classroom - recognize the characteristics of the celestial bull as a harm
1. Habitual symptoms
Overwintering larvae in the Yangtze River Basin begin pupating in March, enter the peak pupae period in early May, feather the adults from mid-April to late May, enter the peak period of adult feathering in mid-May, lay eggs from mid-May to early June, and enter the peak period of larval hatching in mid-June and late June. Adults tend to feather in the morning, then crawl out of the soil, and the body wall and elytra harden and climb onto the hemp plant. When touched, it quickly flies up or falls to the ground to fake death. After feathering, 3 to 5 days after the start of mating, spawning, eggs are mostly laid on the hemp plant about 3m from the ground, the eggs are laid between the xylem and phloem part of the hemp stalk, only 1 grain is laid in each spawning hole, 4 individually, and about 30 eggs per female. The hatching larvae first harm the phloem tissue, and after 7 to 10 days, they moth into the stem marrow, and then invade the dragon head root and the flat root downwards, and eat the hemp. In large occurrences, there are 3 to 8 larvae in the l-hemp pod, and the larvae first bite a hole in the root after maturity, and then plug it with hemp chips or fecal slag to pupate in it. Adults eat petioles and young shoots, causing the hemp plant to produce yellow-brown spots or bite off. The larvae feed on the base of the hemp plant or the underground stem throughout their growth period, destroying the transporting tissue, affecting the transport of water and nutrients, causing the affected area to become black or dry.
Second, the law of pathogenesis
One generation occurs each year, with larvae overwintering in the hemp root at 10 cm below the soil.
3. Morphological characteristics
1. Adult insects. The body length is 11 to 17 mm, and the antennae are the same length as the body or slightly longer. Male adults have sharply rounded elytra wings at the ends; female adults are blunt and rounded, with slightly longer tail segments in the abdomen, and a longitudinal groove in the center of the ventral surface. The dorsal plate of the anterior thorax is pale green, with 2 round dark spots juxtaposed on the upper body. There are light green and black spots on the elytra, some elytra have 3 dark spots, located at the base, in the middle of the anterior or 1/3 of the anterior end, the third dark spot has 1 light green spot in the middle, and some have 2 dark spots on each elytra.
2. Eggs. Length 1. 9mm, oblong oval, yellowish-white, later yellowish-brown.
3. Larvae. Body length 25mm, milky white, head reddish brown, the front half of the dorsal plate of the forebreast is smooth, with yellow-brown bristles, the posterior half has a convex pattern composed of brown grain points, and the back of the hind breast and abdomen l~ 7 segments each have a oblong oval transverse groove, surrounded by brown grain spots. The pupa is 14 to 20 mm long, milky yellowish white, and has two brown rings at the tail end.
Fourth, agricultural prevention and control
1. Use the adult pseudo-death to manually kill in the morning or evening of the adult blooming period.
2. When harvesting hemp head, cut the hemp plant on the ground, which can destroy some eggs and larvae. Try to peel the hemp during larval hatching or poison the hatching larvae in combination with hemp pod irrigation. When arranging the new ma field, the pods need to be insect-free. In order to prevent the spread of sesame seeds, the seeds cut in winter should be placed in cold water for 24 hours, dried and then planted
3. Before the adult worms lay eggs, spray (sprinkle) (2) 5% B dioxide per 667m2 1~1. 5 kg or 90% crystalline enemy insect l000 times liquid, starting from around the field, gradually moving towards the middle, to prevent the adult worms from escaping out of the field.
4. When necessary, use 90% crystalline dimethoate 700 to 800 times liquid or 10% tea seed cake infusion to pour hemp and poison the hatching larvae.