Rice planthoppers are the most common and damaging migratory pests in rice production. They mainly include two types: brown planthoppers and white-backed planthoppers. They are characterized by strong outbreaks, rapid spread, and high concealment, and occur in rice-growing areas throughout China. This pest primarily damages the lower and middle parts of the rice stalks. If control is not timely, it can easily cause "hole-piercing lodging, drying up, and total crop failure" in the field, making it one of the main pests leading to reduced rice yield and quality.

I. Characteristics of Damage: Piercing and Sucking, Indirect Virus Transmission

Adults and nymphs of rice planthoppers congregate at the base of rice plants, sucking sap from the rice. Their damage occurs in three main ways: First, direct piercing and sucking, leading to a large loss of nutrients and water from the rice plant. Mild cases result in yellowing of lower leaves and reduced tillering; severe cases cause large areas of rice plants to wither and collapse, forming devastating symptoms such as "hole-piercing" and "planthopper burn," ultimately resulting in a complete crop failure. Secondly, they secrete honeydew. The honeydew excreted by rice planthoppers after feeding can breed sooty mold, affecting leaf photosynthesis and reducing the fullness of rice grains. Thirdly, they spread viruses. Brown planthoppers can transmit rice tooth-leaf dwarf disease, while white-backed planthoppers are the main vectors of southern rice black-streaked dwarf disease. Once the disease occurs, it often causes irreversible yield loss. Because rice planthoppers often lurk at the base of the rice stalk, they are not easily detected in the early stages. By the time the upper leaves turn yellow, the insect population in the field is often out of control.

II. Control Strategies: Ecological Regulation as the Main Approach, Scientific Pesticide Use as a Backup

1. Agricultural Control as the Foundation. Selecting insect-resistant (tolerant) varieties is the fundamental measure. In cultivation management, avoid excessive nitrogen fertilizer, as too much nitrogen fertilizer will cause the rice plants to be tender and green with soft stems, which will attract rice planthoppers to lay eggs. Promote wide and narrow row planting and intermittent irrigation to reduce field humidity and worsen the environment for rice planthopper occurrence. After rice harvest, timely plowing and stubble removal should be carried out to reduce overwintering insect sources.

2. Biological Conservation to Strengthen Natural Enemies. Rice planthoppers have a rich variety of natural enemies in paddy fields, including spiders, black-shouldered green mirid bugs, ladybugs, and parasitic wasps. The most effective way to protect these natural enemies is to plant flowering plants such as soybeans, sesame, and cosmos along the field ridges, providing them with nectar sources and shelter. At the same time, avoid using broad-spectrum insecticides in the early stages of planthopper infestation to prevent accidental harm to natural enemies.

3. Scientific pesticide application as a safety net. The tillering and booting stages are key control periods. When the planthopper population reaches 1000 per 100 plants, timely pesticide application is necessary. Prioritize highly effective and low-toxicity pesticides such as triflumezopyrim, pymetrozine, and thiamethoxam, focusing on spraying the lower and middle parts of the rice plants to ensure thorough and even application. Rotate different pesticides to prevent pesticide resistance. After heavy rains and strong winds, timely follow-up checks and re-application are necessary to thoroughly suppress the planthopper population, prevent large-scale outbreaks, and ensure stable and high rice yields.