Some measures for caring for and controlling pests and diseases in rice crops.

Rice plants are divided into two growth and development stages, so the following care and cultivation measures should be implemented:

Phase 1 is from sowing seedlings to heading. However, the crucial and decisive period is the tillering stage. The goal is to achieve the largest and most concentrated tillers to maximize the number of tillers for the highest panicle yield. During the tillering period, rice requires 85-90% of the total investment in nitrogen fertilizer. Therefore, the appropriate fertilization method is: Apply 100% well-rotted manure, phosphorus, lime, 2-3 kg of urea nitrogen fertilizer, and 1-2 kg of potassium per sao (if using NPK, apply 30-35 kg of NPK (5-8-5, 5-10-3, or 6-8-4; for Huu Nghi NPK, apply 10-12 kg per sao) and do not need to apply additional nitrogen and potassium fertilizers).

For topdressing during tillering, rice requires 5-7 kg of urea nitrogen and 1.5-2 kg of potassium per sao (approximately 1000 square meters), or 10 kg of high-grade NPK fertilizer from Huu Nghi or Tien Nong, such as 20-5-10, 15-5-10, or 13-13-13. Apply all fertilizer in one go when the rice plants recover their green color and new leaves appear. When fertilizing, pay attention to maintaining a shallow water level of 3-7 cm and keep it consistent for 20-25 days. Fertilizer should be applied in the early morning or late afternoon and combined with mud stirring to safely retain the fertilizer in the soil and prevent loss.

During the tillering stage of rice (approximately 25 days after applying topdressing), maintain consistent moisture levels of 90-100%. Avoid prolonged drought or waterlogging. This will reduce nitrogen and potassium costs, promote rapid tillering, and allow for pest control.

Regarding pests and diseases at this stage, the main pests are leaf-rolling caterpillars and stem borers (second and third generations of the year). Usually, their density is still low, and the rice plants are growing rapidly, so prevention and control are mainly achieved through spraying and manual methods.

In the second stage: From tillering to heading and ripening, this is the crucial stage for achieving the highest yield. During heading, panicle formation, flowering, and grain production, the rice plant requires a balanced and, most importantly, potassium fertilizer to enhance photosynthesis and respiration, creating the conditions for the components of the final product (large panicles, many panicles, many grains, uniform grains, and rapid heading).

Therefore, the main fertilizer application should be red potassium fertilizer at 4-7 kg/sao (if the rice is deficient in nutrients and the plants are yellow, apply 1.5-2 kg of urea nitrogen) or 10-12 kg/sao. When applying fertilizer, observe the rice plants and leaves; the plants should have a round base, straight, pointed leaves, and leaves that are more prominent and constricted at the waist. The water level should be shallow (5-7 cm, or 10 cm), and fertilization should be done in the cool afternoon.

Regarding pest and disease control, this stage is crucial. Failure to implement thorough measures can easily lead to losses and even crop failure. This is because there are many pests such as leaf-rolling caterpillars, stem borers, brown planthoppers, etc., and diseases such as leaf blight, bacterial leaf spot, and black kernel disease can cause significant damage.

The causes are the impact of weather, unbalanced care leading to excess nitrogen in the plants, and high humidity, which creates favorable conditions for pest and disease outbreaks. Towards the end of the season, leaf-rolling and stem-boring insects (4th, 5th, and 6th generations) increase dramatically in both scale and density. Therefore, outbreaks can easily occur, causing localized yield losses in small areas.

Therefore, pest and disease control measures during this stage are: Regularly and periodically inspect and monitor the level of pest and disease outbreaks to implement thorough control measures. Follow the instructions of the commune and agricultural cooperatives based on notifications and directives from the province and district. 12-15 days before the rice plants flower, thoroughly and completely spray to control pests. It is essential to use the correct techniques regarding concentration, dosage, and ensure even coverage.

According to baothanhhoa - LY