Outbreak of leaf roller 5

(Baonghean) - According to data from the Nghe An Department of Crop Production and Plant Protection, as of July 19, the whole province had more than 16,000 hectares of summer-autumn rice infected with small leaf rollers.

Localities need to isolate rice areas infected with leaf rollers. Only areas with a density of over 50 insects/m2 can spray pesticides.

Summer-autumn crop - the whole province planted over 79,687.9 hectares, of which summer-autumn 49,300 hectares, winter-spring crop 30,387.9 hectares. Recently, the weather has been alternating between rain and sunshine, creating favorable conditions for small leaf rollers to develop on a large scale.

Ms. Hoang Thi Hoa's family, hamlet 1, Lang Thanh commune, Yen Thanh district, planted nearly 4 sao of summer-autumn rice. Ms. Hoa said that after the rice plants began to tiller, small leaf rollers appeared, but the density was not high, so the family did not spray pesticides. Hearing the commune announce on the loudspeaker that these days the leaf rollers hatched at the 5th generation, the couple regularly visited the fields. If the density of worms was high, the family would buy pesticides to spray to prevent them according to local instructions.

The chart shows the area of ​​rice infected with leaf roller in the whole province.

Mr. Nguyen Van Trung - Head of the Plant Protection Station of Yen Thanh district said: Up to now, Yen Thanh has more than 2,500 hectares infected with leaf rollers, of which more than 1,000 hectares are heavily infected. Currently, the Station's staff is at the grassroots level to coordinate with local authorities, delimit areas, and guide farmers to spray pesticides according to the recommendations of specialized agencies.

In Thanh Chuong, according to the inspection of the Plant Cultivation and Plant Protection Station of Thanh Chuong district, as of July 19, 2016, the summer-autumn rice in the district is in the stage of heading, the main crop is in the final stage of tillering - standing, the late crop has started tillering. In general, the rice growth and development is poor (due to severe drought), greatly affecting the ability to resist pests and diseases. Meanwhile, the first instar larvae have begun to appear with an average density of 30 - 40 larvae/m2; In high places: 80 - 100 larvae/m2 in the communes of Thanh Yen, Thanh Luong, Xuan Tuong, Dong Van, Thanh Dong, Thanh Van, Thanh Linh, Vo Liet... In particular: over 200 larvae/m2 in Thanh Yen commune. The larvae will continue to increase in density in the next few days because the eggs continue to hatch.

Infected rice area

The weather has been erratic, and in recent days, the fifth generation of leaf rollers has appeared in the summer-autumn rice fields in Nam Dan, causing damage at high density.

According to statistics from the district Plant Protection Station, up to now, Nam Dan has 1,200/6,000 hectares of rice infected with leaf rollers, of which over 100 hectares are heavily infected, concentrated in the communes of Nam Tan, Nam Loc, Nam Hung, Nam Thai with a common density of 30-25 worms/m2, in some places 100-150 worms/m2. It is forecasted that in the coming time, the fifth generation of leaf rollers will likely develop at high density and cause damage on a large scale. In addition, the risk of overlapping generations is very difficult to control. In this situation, the district Plant Protection Station has sent staff to the grassroots level, directly instructing people to spray with specific pesticides, combine care, and apply balanced and technical fertilization, creating conditions for rice plants in the stage of laying - standing to continue to grow and develop well.

Mr. Nguyen Tien Duc - Head of the Provincial Department of Crop Production and Plant Protection, said: As of July 19, the whole province had 16,168 hectares of summer-autumn rice infected with leaf rollers. Of which, 2,525 hectares were lightly infected, 4,210 hectares were moderately infected and 9,433 hectares were heavily infected. In the key areas, Yen Thanh had 2,500 hectares, Dien Chau 6,460 hectares, Quynh Luu 6,255 hectares. The fifth generation of leaf rollers began to hatch from July 18 to 23.

Thus, the 5th generation of worms is likely to arise at a density many times higher than the 4th generation on a large scale. The worms cause damage during the early summer-autumn rice and the main crop, which is in the heading stage, which will greatly affect the yield because at this stage the rice plant is no longer able to produce new leaves. Especially in the 5th generation, there will be an overlapping phenomenon, so the damage caused by the worms will last longer, making it difficult to direct prevention and control work.

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