The rice leaf roller, a major pest in rice fields, causes significant damage by feeding on the leaves of rice plants. The larvae roll the leaves into tube-like structures and feed on the epidermis and leaf flesh, resulting in widespread white leaves. This is especially problematic in the later stages of early rice, when the functional leaves are damaged, affecting the development of the late-season basal tillers in late-maturing rice varieties. As a result, this pest has become a key factor in reducing early rice yields, making timely control essential.
In recent years, the occurrence of the rice leaf roller has been almost annual. Since late June, large numbers of adult insects have migrated into the area, and prolonged rainy weather has facilitated their movement. This leads to heavy infestations during the middle and late growth stages of early rice, with white leaf rates typically ranging from 20% to 25%, and sometimes reaching as high as 60% to 70%. In some cases, entire fields are completely whitened. If not controlled in time, it can cause severe losses, particularly for early and late-season rice crops.
To effectively manage the rice leaf roller, the strategy should focus on "treating early and addressing small issues before they escalate." Monitoring insect populations and weather conditions is crucial. Pesticides should be applied before the third instar stage of the larvae—ideally at the initial tip of the leaf. This helps reduce the base population and eases the burden of later-stage control. It's important to act during the peak egg-hatching period or when young larvae are active. Typically, spraying should begin when there are 15 or more new leafhoppers per hundred clumps, or when larvae are in the second or third instar stage.
In years with early infestations and heavy populations, it's advisable to apply pesticides in the later stages of rice growth. This not only controls the current infestation but also reduces local insect populations, lowering the pressure for future control efforts—a method known as "pre-government control."
For effective control, choose high-efficiency insecticides and spray them evenly during the first leaf stage or two days after the egg-hatching peak. Recommended options include: Chlorpyrifos (48% EC) at 60–100 ml; Fipronil (5% Suspension) at 40–50 ml; 10% Furanofos Suspension at 100–120 ml; 40% Profenofos EC at 100–120 ml; 50% Monosultap WP at 100–120 g; and 18% Insecticidal Double Water at 300–400 ml. After application, older larvae may not die immediately, but their feeding activity will significantly decrease, offering long-term protection for up to 24 days. The treatment remains effective even if rain occurs within 12 hours of spraying. Spraying should be done with sufficient water to ensure thorough coverage, and mist sprayers should be avoided.
By mid-July, most larvae have advanced in age, making control more difficult and costly. If the number of curled leaves and white leaves increases significantly, high-dose applications of Avermectin or similar agents can be used for a single treatment to minimize damage. Focus on spraying the affected areas thoroughly, ensuring full coverage and penetration.
Newer insecticides available for controlling rice leaf rollers include 5% Buteneflupron EC, Flufoxin (also known as XeroxBao), and Emamectin Benzoate. For those who prefer traditional options, high-toxicity pesticides can also be used according to technical guidelines and market availability. Always follow label instructions for safe and effective use.
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