<h1 class= "pgc-h-arrow-right" >, distribution, and hazards </h1>
Rice leafminer is a common name for rice hairy eye water fly pests that are harmful to rice, also known as rice leaf diving fly, belongs to the diptera water fly family, known around the world at least 3 species: rice leaf hair eye water fly, oriental hair eye water fly and small gray hair eye water fly, China only the first two species of distribution. Different species of hairy-eyed waterflies are similar in morphology and are highly confusing. In China, it has been reported that in the northeast and north China rice areas harm rice small leafminer fly, also known as rice leaf diving water fly, rice small diving fly, mantis fly, rice small water fly, wheat leaf hair eye water fly, barley water fly, wheat water fly, after the 1980s Fan Cide, Luo Xiaonan and Huang Bangkan and others identified, in fact, including the rice leaf hair eye water fly that harms rice and wheat and the wheat sheath hair eye water fly that harms wheat and barley, while the real (small gray hair eye water fly) is distributed in the Americas, Europe and Asia in Japan, and china has not seen distribution. In recent years, the phenomenon of mistaking the scientific name of the small leafminer fly in the literature is still relatively common and needs attention.
Rice leaf hairy water fly is commonly found in the northern rice area and the middle and lower reaches of the Yangtze River, while the eastern hairy eye water fly is found in anhui, Hunan, Fujian, Guangxi and other southern rice areas. Rice leaf hairy eye water fly was originally an important pest of rice seedling stage in northern rice areas, but since the 1970s, due to the early sowing and planting period of rice and the promotion of direct rice, it has also caused considerable harm to rice in the tillering stage of Honda, and is an important pest in the early stage of rice growth in North China and Northeast China. In the double-cropping rice planting area in the middle and lower reaches of the Yangtze River, it is an occasional pest at the early rice seedling stage, and the early rice transplanting time is early, and the low temperature weather in spring is conducive to its occurrence. However, since entering the 21st century, rice-water leafminer flies have only occurred heavily in the northeast, such as Haicheng, Liaoning Province, which has shown a gradual aggravating trend with the change of farming system, which can generally cause a reduction in yields of 5% to 10%, and a reduction of 20% to 30% in serious plots. In the Tiger Forest Area of Heilongjiang Province, it occurs to varying degrees every year, often reaching 100% of the occurrence area, and the yield of the generally affected plots is reduced by 10% to 20%, and the serious ones can reach 60%.
< h1 class="pgc-h-arrow-right" >2, symptoms </h1>
In addition to rice, the hosts of the small leaf-diving fly also include barley, wheat, oats, wheat, long mango, Japanese wheat, Lee's barnyard, grass, stick grass, dog tooth root, Northeast sweet grass, seabump triange and other grasses, sedges, but also eat buttercup family of Shilongrui, Tiannanxing family calamus and other plants.
Small leafminer flies are harmed by leaf-diving by larvae. The larvae burrow into the young rice leaves, feed on the leaf flesh between the upper epidermis, the leaf epidermis remains, and the affected leaves show irregular white stripes, of which milky white to yellow-purple elongated maggot-shaped larvae can be seen, and each leaf is as few as 2 to 3 submarines and as many as 7 to 8. The damaged area initially appears on the leaf surface of the sesame grain-sized curved "worm bubble", and later with the expansion and elongation of the insect path, the formation of yellow-white dead spots, the lower affected leaves of the rice plant hang into the field water, decay occurs, and in severe cases, the rice seedlings can wither in pieces.
<h1 class= "pgc-h-arrow-right" > third, prevention and control technology </h1>
Comprehensive control measures that combine agricultural control and chemical control should be adopted.
1. Agricultural control
1> weed removal Remove grass weeds at the edge of the field, ditch edge and low terrain can effectively reduce the source of insects and thus reduce the harm to rice.
2> cultivate strong seedlings, shallow water irrigation Layer depth is within 5cm, to promote the occurrence and growth of new roots of rice seedlings, especially in the adult spawning peak 7 to 10 days, shallow water irrigation pest control effect is better.
3> level the land, drain the sun to level the land, ensure the healthy growth of rice seedlings in the same water layer, reduce weak seedlings, and reduce the probability of adult spawning. Serious plots, through drainage and drying of the field, reduce the humidity of the field, which is not conducive to the development of larvae, and its development and harm can be effectively controlled.
2. Chemical control
The focus of pharmaceutical control is on early rice seedlings and early sowing and early planting of young green seedlings in the early rice fields. During the application period, it is advisable to transplant rice to return to green and resurrect, maintain a depth of about 5 cm of field water before spraying, and then irrigate after 1d of application.
At the peak of adult insect occurrence, spray 2.5% diost powder 1.5 to 2.0 kg per 667 m2, or use 2.5% dio worm powder plus 1.5% Leguo powder to mix well at 1:4 and then use 2 kg per 667 m2.
During the larval stage, 40% Lego emulsion 1000 to 1500 times liquid, 90% dichlorvos soluble powder 800-1000 times liquid, 80% dichlorvos emulsion 1000 times liquid, 50% borage pine emulsion 1000 times liquid, 50% malathion emulsion 1000 times liquid, 25% iminothion emulsion 1000 times liquid, 10% imidacloprid wettable powder 2500 times liquid spray, every 667m2 spray liquid 45 ~ 60L. Every 667 m2 with 3% g of Budweiser granules 2 kg mixed with fine soil 20 kg evenly spread, there is also a good anti-effect.
Source: Crop Diseases and Pests in China
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