Recently, white spots and slender cracks have been found in the heart leaves of rice in the field, and pale yellowish-white insects have been peeled off in rice, which have been judged to be rice stalk diving flies. Rice stalk diving flies mainly burrow into rice stems with larvae to feed on heart leaves and young ears, and generally the first hatching larvae will appear to be killed after 5-8 days of drilling. The insect is widespread in the southern mountains and hilly rice of Guangdong, Yunnan, Hunan, Jiangxi and other provinces, and the local areas are seriously affected. The following small series will talk to you about the harmful characteristics and prevention of rice stalk diving flies.
Rice leaf symptoms in the field
<h1>First, the harmful symptoms of rice stalk diving flies</h1>
At the seedling stage, there are many slender cracks on the extracted heart leaves, which are yellowish-white from the edge of the cracks, and the edges of the leaf cracks drawn out when the heart leaves are wet will rot and have a putrid odor; the injured seedlings are light and weak, and the heart leaves are dead severely, and there will be an increase in tillers in the later stage, and the panicle cannot be pumped or the panicle is late and the panicle head is small.
Young larvae have small feeding holes, and the heart leaves have a row of small holes after unfolding, resembling a pest of rice weevils. The difference between the two is that the rice elephant beetle is diamond-shaped and does not rot around the orifice; the rice stalk fly is rarely rounded, most of which is longitudinally cracked, and the orifice is rotted around the orifice.
Pregnant panicle stage victimization, yinghua degeneration, can not form normal grain, after the panicle shows panicle shape distortion, some spikelets are untrue or deformed small ying shell, showing a "brush head", white ying shell has holes, there will be rot around the performance, serious formation of white spikes, similar to the hazard of dimorphic borer.
<h1>Second, the identification points of rice stalk diving flies</h1>
Adult rice stalk flycatcher
Adults have diamond-shaped black spots on the back of the head, 3 long black spots on the back of the thorax, and black-brown transverse bands on the dorsal front edge of each segment of the abdomen.
Rice stalk fly larvae
The larvae are maggot-shaped, pale yellowish-white, and the old mature larvae are milky white, about 6 mm long, nearly spindle-shaped, and the tail end is divided into 2 forks.
<h1>Third, the occurrence of rice stalk diving flies</h1>
Rice stalk diving fly occurrence and rainfall, temperature has a lot to do with, adult insects like cool, humid, rainy years, egg hatching rate is high, larval survival rate is high, the amount of occurrence is large; when the temperature exceeds 35 ° C or more, the larval development is hindered, high temperature drought is not conducive to egg hatching. The hatched rapeseed is moistened by rain and dew and moved downwards, burrowing into the leaf sheath at the leaf pillow and then invading the heart leaf.
According to the observation of field occurrence, the mountain fields with high terrain, wet and foggy terrain are generally heavier than the fields and plains fields; the partial application and late application of nitrogen fertilizers and the heavy occurrence of green and tender fields with rice leaves are mainly due to the fact that the adult eggs of the rice stalk diving fly have tender greening.
<h1>4. How to control rice stalk diving flies? </h1>
The applicable agents for the control of rice stalk diving flies are: avermectin, methyl vitamin salt, chlorpyridine benzamide, imidacloprid, thiamethoxam, high efficiency cypermethrin, chlorpyrifos, triazoliphos and other pesticides, long-term use of chlorantraniliprox benzamide, if you want to achieve rapid results, you can add avermectin; fast-acting short-term and low-cost, you can use mevin salt + high-efficiency cypermethrin or organophosphorus pesticides.
Appropriate period of drug control: in the adult bloom period or the peak period of egg hatching; precautions: can be combined with the prevention and control of dimorphic borer, rice longitudinal leaf borer for prevention and control, spraying focus on spraying heart leaves, and maintain a shallow water layer in the field, which is conducive to improving the prevention effect.
In addition to medication, the following agricultural measures need to be taken:
(1) Reasonably select rice varieties, sow seeds in a timely manner, and avoid the seedling stage and the peak period of adult egg laying;
(2) Strengthen water and fertilizer management, avoid partial application and late application of nitrogen fertilizer, increase potassium fertilizer, make rice grow robustly, and help reduce the base of occurrence of latent leaf larvae in the field.
(3) Worsening the living environment of overwintering adult insects and removing weeds around the rice field in winter and spring can effectively reduce the source base of insects after winter.
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