Wheat straw fly

Scientific name MeromyzasaltatrixLinnaeus Diptera, Stem Muscidae. Distribution from Heilongjiang, Inner Mongolia, * * in the north, Guizhou and Yunnan in the south, Xida * *, Xizang. It also occurs in Hainan in Qinghai, Ganzi and Aba in Sichuan. The damage is serious in Inner Mongolia, Ningxia and parts of Hebei, Shanxi, Shaanxi and Gansu.

Host @, barley, oats, alkali grass, white thatch, etc.

The characteristic of the damage was that the larvae drilled into the stem of hosts such as wheat, and the newly hatched larvae drilled into the wheat stem from the leaf sheath or stem internodes, or spirally downward at the base of the young heart leaf and spike node, forming withered heart, white ear and rotten ear, which could not bear fruit.

The male adult is 3-3.5mm long, the female is 3.7-4.5mm, the body is light yellowish green, the compound eye is black, the chest is covered with three black or dark brown longitudinal lines, and the middle longitudinal grain is wide in front and narrow in back, directly connected to the end of the posterior edge, the longitudinal lines on both sides are only half or more than the middle longitudinal lines, and the ends are bifurcated. The antennae are yellow, the cheeks are black and the base is yellow. The feet are yellow and green. The hindleg segment is enlarged. Egg-long 1mm, spindle-shaped, white, with 10 longitudinal lines on the surface mask. The body length of the last instar larvae is 6-6.5mm, yellowish green or yellowish green, maggot-shaped. The pupa belongs to the peripupa, the male body is 4.3-4.7mm, the female is 5-5.3mm, the pupa shell is transparent, and the compound eye, chest, abdomen and so on can be seen.

The living habits are 2 generations a year in spring wheat areas such as Inner Mongolia and 4 generations in winter wheat areas. Larvae survive the winter in host rhizomes or soil crevices or weeds. In the spring wheat area, the overwintering adults began to appear in the first and middle of May, entered the peak period at the end of May and the beginning of June, the spawning peak was in the middle and late June, the eggs were hatched after 7 days, and the larvae were in the peak stage in late June, which was about 20 days. Pupation occurs in the first and middle of July, and the pupal period is 5-10 days. Most of the first generation larvae emerged and left the wheat field before wheat harvest in mid-late July, laying eggs on perennial Gramineae weeds. Wheat stalk flies damage wheat by only one generation of larvae in Inner Mongolia, and the adults lay eggs at the base of the leaves after Eclosion. In winter wheat area, the 1st and 2nd generation larvae damaged wheat in April and May, the third generation transferred to autogenous wheat seedlings, and the fourth generation transferred to autumn seedlings. Henan also has two peak periods of harm in a year. After maturing, the larvae overwintered on the damage or wild host. Adults have phototaxis and chemotaxis. Adults mate on the same day after Eclosion and are active among wheat plants during the daytime. Eggs are mostly laid on 4-or 5-leaf wheat stems, and eggs are scattered. Each female can lay more than 20 eggs, as many as 70-80 eggs. The insect needs high humidity for oviposition and larval hatching. Wheat varieties with soft stems, wide leaves or few hairs have high oviposition rate and serious damage.

Control methods (1) according to local conditions, select suitable local insect-resistant or early-maturing varieties. (2) strengthen cultivation management to achieve early sowing and reasonable close planting at the right time. Strengthen the management of water and fertilizer to promote the neat growth of wheat. Speeding up the early growth and development of wheat is the fundamental measure to control the pest. (3) strengthen the prediction of wheat straw flies: the winter wheat area begins to check insects in the middle and late March, and the spring wheat area begins to check insects in the middle of May. Every 3 days, the net is swept 200 times at the top of the wheat seedlings around 10:00. When there are 3 insects in the 200 nets, it is the peak emergence period of adults in the overwintering generation after about 15 days, which is the first suitable period for chemical control. In winter wheat area, there are an average of 25 insects in 100 nets, which need to be controlled. (4) when the adult wheat straw fly has reached the control target, 2.5% trichlorfon powder or 1.5% dimethoate powder or 1% 1605 powder should be sprayed per 667m21.5kg. (5) if the wheat straw fly has laid a large number of eggs, timely spray 36% acaroid fly EC 1000ml 1500 times or 50% 1605EC 4000 times or 80% dichlorvos EC and 40% dimethoate EC at 1:1, then mix 1000 times of water or 3000 times of 10% Maxiong wettable powder and 3000 times of 25% aldicarb wettable powder, and spray the right solution of 50ml 75L per 667m2 to control the eggs before hatching.