Northeast big black Gill beetle

Holotrichia diomphalia Bates

[Damage crops] Damage beets and all kinds of vegetables, but also damage legumes and grass crops.

(Pest identification) The larvae damage the roots and stems of vegetable seedlings, causing the whole plant to die, resulting in lack of seedlings and broken ridges; they also nibble on root tubers and tubers, affecting quality. Adults feed on crop leaves, especially soybean, peanut and other crops, holes or notches. Northeast black gill beetle belongs to coleoptera, cheloniaceae. Adult body length 16~21 mm, width 8~11 mm, black or dark brown, shiny. The antennae are tan. Both sides of the protoplate arc. scutellum subsemicircular. The elytra is long elliptic, each elytra has 4 longitudinal ribs. There are 3 teeth on the lateral side of the forefoot tibia and 1 root on the medial side. The egg is about 2.5 mm long, white, oblong at first birth and round at later stage. The larvae are grubs. Larvae mature body length of 35~45 mm, yellow head, body milky white, static was "O" type. The anterior parietal setae of the head are 3 on each side, in a column. Anal spineless hairs. Pupa length 21 - 23 mm, yellow or yellow-brown, tail segment narrowly triangular, upper wing, end with a pair of divergent tail spines (Figure 36).

[Living habits] The northeast black gill beetle has one generation every two years, and adults and larvae alternate to winter every other year. Adults appear from late April to early May, a large number of emergence period from May to June, the middle and late June for spawning peak period, the middle of July for egg incubation peak period, mid-October, larvae drill into the frozen soil layer for winter. The overwintering larvae rose to the topsoil in the first and middle May of the next year, and the serious damage period was from late May to early June. 7~9 months old mature larvae into the soil room pupation, after about 20 days to emerge into adults, do not emerge in the year, overwinter in the soil room. It was not until late April of the following year that it began to be unearthed. Adults lurk in the soil during the day and feed after dusk. Adults have pseudolethality. Male insects have strong phototaxis and have tropism to undecomposed manure. Adults mate at night and lay eggs 10 - 15 days later. Adults like to eat soybean, peanut and other crop leaves, and lay eggs in these field soils. Each female lays more than 100 eggs in her life. The development period of this insect is: egg stage 15~22 days; larval stage 340~400 days; pupal stage about 20 days; adult stage about 300 days. Soil temperature and humidity have direct influence on the activity of grubs. When the soil temperature is 22~23℃ at 10 cm depth, the grubs mostly move at 10~20 cm depth. If the soil temperature is 5~10℃, they move downward. The optimum humidity is 15%~20%.

(1) The land is cultivated. Autumn crops after harvest, should be timely autumn ploughing, can overwintering adults, larvae frozen to death, or preyed by birds. (2) Application of fully decomposed manure to mitigate grub damage. (3) Artificial control. In spring, artificial plows pick up insects to reduce the number of insects. After planting vegetables, if grub damage is found in the field, it can be inspected one by one and killed. (4) Control adults. At the peak of adult development, spray 50% phoxim EC, or 90% crystalline trichlorfon 800~1000 times, or 25% quinothion EC 1500 times, or 40% dimethoate EC 1000 times, or 2.5% cymethrin EC 3000 times. (5) Control of larvae. Poisoned soil: 50% phoxim emulsifiable concentrate, or 90% trichlorfon, or 25% dicongling microcapsule suspension agent, 1.5~2.25 kg/ha, diluted with a small amount of water, mixed with 225~300 kg of fine soil, applied to seedling holes, the toxic soil covered with a layer of soil, so that seedlings and toxic soil isolation, to avoid phytotoxicity. Root irrigation: in the larval occurrence of more plots, can also be used above chemicals root irrigation.