Green leafhoppers, Empoasca kerri, E. binotata, and E. flavescens, belong to the family Cicadellidae and are important agricultural pests that infest many crops, including green gram. Leafhoppers infest various host plants, including green gram, black gram, and cowpea, causing significant damage to these crops.
These leafhoppers cause significant damage to plants by piercing and sucking on the sap from plant tissues, leading to yellowing, stunted growth, and reduced yield. Green leafhopper infestation in green gram is a major concern for farmers, especially in tropical and subtropical regions, where warm and humid conditions provide a suitable environment for their growth and reproduction.
Several management strategies are available to control green leafhopper infestation in green gram, including cultural, biological, and chemical methods. Crop rotation, intercropping, and timely sowing can lower pest populations by disrupting their life cycle and limiting host availability. Biological control uses predatory insects, parasitoids, and diseases to reduce green leafhopper populations. Insecticides kill or prevent green leafhoppers.
Green Leafhopper Management in Green Gram
Identification of Green Leafhopper
Green leafhoppers are elongated, wedge-shaped, and active insects that their green color can identify. They are the primary pests of green gram, black gram, and cowpea and cause damage by piercing plant tissues and sucking the sap. The salivary toxins they introduce during feeding can damage plant tissue and impair photosynthesis, reducing crop yield and quality. In addition to visual identification, green leafhoppers can be detected using sticky traps and sweep nets.
The Life Cycle of Green Leafhopper
The life cycle of the green leafhopper of green gram begins with laying eggs in batches inside the leaf sheaths and on the leaf midribs. The eggs hatch in 7-9 days, giving rise to brown nymphs. Over the next 13-15 days, the nymphs molt five times, gradually developing into adult insects. During this time, they feed on the sap of the host plant and can cause significant damage.
4-8 days is the Incubation period. Each of the five nymphal instars lasts between 7 and 10 days. Once they reach adulthood, the green leafhoppers are active, elongated, wedge-shaped, and green in color, capable of reproducing and continuing the life cycle.
Causes/Conditions Favorable for Green Leafhopper Spread in the Field
Green leafhoppers thrive in moderate to high temperatures and humidity levels ranging from 21 to 31°C and 55 to 85%, respectively. These conditions favor their growth, development, and reproduction and contribute to their spread in green gram fields. In contrast, low temperatures and strong winds inhibit their activities and can limit their ability to feed and reproduce.
Damage Symptoms of Green Leafhopper
- The primary damage symptoms include yellowing and mottling of the leaves, which is caused by the insects sucking the sap of the plants.
- Infested plants will have green-colored insects visible on the undersides of leaves.
- As the damage progresses, the affected leaves will turn yellowish, then brownish, starting from the margins and moving toward the midrib.
- The leaves will gradually curl before drying completely and shedding.
- The infestation of green leafhoppers can also significantly reduce the fruiting capacity of the plants, leading to lower yields.