<h1 class= "pgc-h-arrow-right" >, distribution, and hazards </h1>
There are four main species of leafminer flies that harm wheat in China, namely: thin-stemmed leafminer fly, black spotted leafminer fly (toothed horned leafminer fly, sheath tooth horn leaf diver fly), black orbital grass leaf diver fly (yellow horn diver fly), velvet eye color diving fly (black color diving fly), all of which belong to the order Diptera, submerged flies. Among them, the fine-stemmed leaf diving fly is also called wheat leaf gray diving fly, wheat black diving fly, Japanese wheat leaf diving fly, which generally occurs more, and the other 3 species occur less.
Leafminer fly larvae submerged on leaf flesh, the latent marks are curved and narrow, mainly harming the lower leaves in the early stage, and later gradually moving up to harm the middle and upper leaves and the tip of the inverted trilobite leaves, and the wheat flag leaf can also be harmed. The affected part of the leaf becomes a transparent epidermis, and in severe cases, only the leaf veins remain, which can cause the wheat leaves to dry out and die, which seriously affects the growth and development of wheat.
There are occurrences in wheat areas such as northwest China, north China, Huanghuai and the lower reaches of the Yangtze River. In 2002, the insect occurred in the wheat field of Jinghai County, Tianjin, and the rate of wheat victimization plants was about 70%; in 2003, the occurrence was more serious, and the general wheat field victimization rate was 40% to 60%, and the serious rate was 70% to 100%. In 2002, the insect was found in Sheyang, Jiangsu Province, which harmed barley and wheat, and the rate of insect fields reached 90%, and the rate of barley wheat victimization plants was 2.5% and 7.4%, respectively. From 2002 to 2003, the harm was relatively heavy in Linfen, Shanxi, and other places, with the general rate of victims being 20% to 30%, and the rate of serious plot victimization was as high as 92%. In Henan Province, in the past, the insect occurred sporadically, but in 2003 it was more common in Zhengzhou City, and some wheat fields were more seriously affected. In Funan County, Anhui Province, the pest was seen in the field in 2004, with the spring March and April as the more serious damage; in 2009, it also occurred in wheat autumn seedlings, and the harm showed an aggravating trend year by year, which has posed a threat to wheat production.
In addition to harming wheat, the insect also harms barley and barley; according to foreign records, the host has rye and grass plants.
<h1 class= "pgc-h-arrow-right" > second, prevention and control technology </h1>
1. Agricultural control
1> preferred breeding of excellent varieties resistant to diseases and insects;
2> avoid sowing too early and sowing late at the right time;
3> strengthen field management, apply nitrogen fertilizer in an appropriate amount, and reapply phosphorus and potassium fertilizers to reduce the harm. Closely monitor the dynamics of insect occurrence during the rejuvenation and jointing periods, control the spawning of adult insects, and eliminate them before harm.
2. Chemical control
Adult control is the mainstay, supplemented by larval control.
1> control of adult insects In early April, the prevention and control is carried out when the wheat emerges in the spring and the winter wheat returns to green. Agent and usage: 2.5% dimethoate powder, 25 kg of fine soil per 667 m22 ~ 2.5 kg mixed with fine soil, or 80% dichlorvos emulsion, add 200 ~ 300 g of water per 667 m2100 g, add 20 kg of fine soil and mix well and spread; or 20% cypermethrin emulsion 1500 ~ 2000 times liquid spray.
2> control of larvae When the rate of affected plants in the field reaches 5%, the following sprays can be selected. 20% Avi kill single microemulsion 1000 to 2000 times liquid, 1% avy fungin 3000 to 4000 times liquid, 4% Avi pyridine 3000 to 4000 times liquid, 0.4% Avi bitter emulsion 1000 times liquid. It can also be sprayed with 40% chlorpyrifos emulsion 50mL or 4% avyl acetidium 50mL, and sprayed evenly at 45kg of water per 667m2, which can also treat other insect pests in wheat fields at the same time. For weak seedlings and yellow seedlings, every 667m2 can be mixed with a large number of elements such as nitrogen, phosphorus, potassium and other elements and amino acids, chelated trace elements of the product, which is conducive to the formation of strong seedlings and improves the cold resistance and stress resistance of wheat.
Source: Crop Diseases and Pests in China
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