Risk of crop failure if we take lightly the prevention and control of leaf roller disease

Currently, small leaf rollers are emerging, developing and causing damage on a large scale with a density many times higher than the average of previous years. Professional agencies warn that if people are subjective and do not spray and control them promptly and properly, the risk of crop failure is entirely possible.

Yen Tu commune leaders and specialized departments inspect and urge pest control work.

Unprecedented depth density

In Yen Tu commune, farmers have never witnessed such a severe outbreak of leaf rollers as this year's Summer-Autumn crop. The pests have damaged over 100% of rice varieties and rice fields in all cooperatives with a density dozens of times higher than the average of many years. Mr. Tran Ngoc Tu, Director of Lien Phuong Cooperative (Yen Tu commune), said: "All 232 hectares of rice of the cooperative are being damaged by leaf rollers, with a common density of 500-700 insects/m2, in some places up to 1,500-1,800 insects/m2. We are extremely worried because these days it has been raining continuously, causing pests to spread and break out more strongly, while prevention and control are also facing many difficulties."

Small leaf rollers are appearing at high density in the fields.

The situation of small leaf rollers is also particularly serious in communes in Giao Thuy, Hai Hau, and Xuan Truong districts of the former Nam Dinh province. Mr. Vu Ngoc Minh, Head of the Hai Hau Plant Protection Station, informed: Almost the entire rice area of 21 communes under the management of the Station is being ravaged by small leaf rollers, of which 20 thousand hectares are heavily infected with a density of up to thousands of worms/m2, along with a very high density of adults and eggs.

According to the Department of Crop Production and Plant Protection, in the 2025 Summer-Autumn crop, the whole province sowed and planted over 127,300 hectares of rice, of which the area infected with small leaf-end borer was nearly 108,200 hectares (accounting for 85%), of which the area requiring spraying was over 90,100 hectares, many times higher than the 2024 Summer-Autumn crop and the average of many years. Of which, the heavily infected area was over 52,800 hectares, concentrated in the communes of Giao Thuy, Giao Hung, Giao Ninh, Xuan Phu, Hai Tien, Khanh Nhac, Yen Tu, Quang Thien, ...

Engineer Dinh Thu Huong, an employee of the Department of Crop Production and Plant Protection, said: small leaf rollers are one of the most serious pests for rice plants, especially during the tillering, panicle differentiation and flowering stages. With a life cycle of only 30 - 35 days and the reproductive capacity of a female butterfly of up to 100 eggs, their reproduction and spread rate is extremely terrifying. Meanwhile, larvae from the age of 2 to 3 have spun silk to roll leaves into bags to survive, so it is very difficult to prevent, if the timing is not chosen correctly, the prevention efficiency is very low.

Small leaf rollers that appear in large numbers in the fields will eat leaf tissue, reducing the photosynthetic ability of the plant, causing poor growth of the rice plant, and the rice field will become white and withered. A small leaf roller can destroy 3-5 leaves in its life cycle. In particular, if the worms damage flag leaves or functional leaves, rice yield will decrease significantly. Moreover, the wounds caused by the worms are favorable conditions for bacteria and viruses to invade and cause further damage to the rice plant.

Experts warn that with the current high density of leaf rollers in the fields, if people are subjective and do not spray promptly and properly, the risk of crop failure is entirely possible.

Race against time, drastic prevention

Faced with the complicated developments of pests and diseases, on August 17, 2025, the People's Committee of Ninh Binh province issued Official Dispatch No. 06/CD-UBND requesting relevant departments, branches and sectors and Chairmen of People's Committees of communes and wards to focus on directing the prevention and control of small leaf rollers that harm the 2025 Summer-Spring rice crop. The Official Dispatch emphasized that the Chairmen of the People's Committees at the commune level are responsible if the disease spreads due to subjectivity and lack of direction.

Officers of the Department of Crop Production and Plant Protection coordinated with the Cooperative to check the density of small leaf rollers in the fields of Hoa Lu ward.

Mr. Nguyen Ngoc Hai, Head of the Economic Department of Yen Tu Commune, shared: Immediately after receiving urgent instructions from the Provincial People's Committee and the Department of Agriculture and Environment, the commune held a meeting to deploy a campaign to prevent and control small leaf rollers for the entire Summer-Autumn rice area from August 15 to present. Heads of departments, branches, and organizations joined in with professional staff and cooperatives to directly go to the fields to grasp the situation, determine the density of pests and direct spraying. The preventive measures were disseminated to households through the loudspeaker system so that everyone knew the level of danger and knew how to spray according to the "4 rights" principle (right medicine, right dosage, right time and right way) to achieve high efficiency. The commune also increased inspection of the business and use of fertilizers and pesticides in the area to ensure that there were no price increases, fake goods, and poor quality goods circulating on the market.

Mr. Tran Ngoc Tu, Director of Lien Phuong Cooperative, added: Despite the continuous rain, we are still very urgent, dodging every hour to spray pesticides. We have mobilized maximum means, especially applying mechanization by drones for spraying. Using drones helps spray pesticides quickly, evenly and does not depend much on the weather. It only takes a few hours to spray a large field. By August 18, the whole commune had sprayed about 73% of the total area that needed prevention. Mr. Tu affirmed that after this period, we will continue to closely follow the fields, monitor the effectiveness, re-evaluate the density of pests to advise people to continue spraying a second time if necessary.

Faced with the complex developments of pests, farmers have actively cooperated with the cooperative. Ms. Le Thi Linh, a farmer spraying pesticides in the rice fields of Yen Tu commune, said: “The rice is in an important growth stage, if it is bitten by pests, it will greatly affect the yield. Therefore, even if it rains, we will go to the fields to spray whenever it stops. We have to eradicate the pests to be assured.”

In addition to the participation of the government, people, and specialized sectors are also actively coordinating to support. The Department of Agriculture and Environment has established working groups to inspect, urge, and guide localities. Officers of the Department of Crop Production and Plant Protection are also "working" to monitor the situation of pests and diseases, accurately determine the density, each generation of pests, and the age of pests to advise localities on the most effective time to spray.

The Department of Crop Production and Plant Protection said that the most difficult thing now is the continuous rain, which makes spraying difficult. In addition, after the merger, the local government operates at two levels, the management area is large but the apparatus is streamlined, the Economic Department staff of the communes take on many tasks, many places do not have specialized staff in the field of crop production and plant protection, creating great challenges in directing pest control. In addition, this year, the small leaf roller appeared about half a month earlier than every year, which led to a subjective mentality among the people that now is not the time to prevent and control. Meanwhile, the Department's staff in charge of plant protection is still thin, so it is necessary to have more drastic direction from local authorities. Only with close and drastic coordination from the provincial level to the commune level, cooperatives and people can we effectively deal with the small leaf roller epidemic, ensuring a successful 2025 Summer-Autumn rice crop.

Farmers in Yen Tu commune spray pesticides to prevent leaf rollers.

The provincial Department of Crop Production and Plant Protection recommends: The time to spray concentrated leaf roller insecticide is from August 18 to 23. Use one of the following pesticides: Incipio® 200SC; Clever 150SC, 300WG; Ammate®150EC; Obaone 95WG, Divine 180SC... according to the manufacturer's dosage; prioritize using specific pesticides Incipio® 200SC; Clever 150SC, 300WG. After 3-5 days of spraying, check if the density of live insects is ≥ 50/m2, spray again immediately.

Article and photos: Nguyen Luu

Source: https://baoninhbinh.org.vn/nguy-co-mat-mua-neu-xem-nhe-viec-phong-chong-dich-sau-cuon-203764.htm