Prevention and Control of Rice Grasshoppers

Prevention and Control of Rice Grasshoppers

Rice grasshoppers refer to pests affecting rice, with over 17 known species in China. The most widespread and damaging is the Chinese rice grasshopper, found in almost all rice-growing regions. Let's learn about the prevention and control methods for the Chinese rice grasshopper.

Prevention and Control Methods for Chinese Rice Grasshoppers

Damage Caused by Chinese Rice Grasshoppers

Both adult and nymph Chinese rice grasshoppers feed on rice leaves and small spikes. Mild infestations result in notched leaves, while severe infestations can strip the leaves entirely, leaving only the main veins. After rice heads, grasshoppers can cut small branches or cause broken spikes and white heads. During the milk stage, they may eat the milky grains directly. At the yellow ripening stage, they can knock off the grains, affecting yield.

1. Habitat Destruction

Chinese rice grasshoppers prefer to lay eggs in field ridges, canal slopes, and wastelands. Timely removal of weeds around the field edges, reducing wasteland areas, reclaiming wastelands, maintaining field ridges, and clearing silted dikes can destroy breeding sites.

2. Cultivation Management

Timely sowing, appropriate fertilization, and water management can promote robust growth of rice, making it less susceptible to grasshopper damage.

3. Biological Control

Releasing ducks to eat the grasshoppers or protecting natural predators like frogs, toads, spiders, and parasitic wasps can effectively suppress grasshopper populations. To protect these natural enemies, use high-efficiency, low-toxicity, and environmentally friendly pesticides during chemical control.

4. Chemical Control

In fields close to ditches and wide ridges that are conducive to grasshopper egg-laying, use the edge spraying technique, spraying within 2 meters of the field edges. Suitable pesticides include those that also control borers, planthoppers, thrips, aphids, and leafhoppers. Recommended pesticides: Chlorpyrifos and triazophos mixture, or monocrotophos and chlorpyrifos mixture, or chlorantraniliprole, or malathion and chlorpyrifos emulsion, or monocrotophos and Beauveria bassiana. Follow the instructions carefully for safe and scientific use.

In summary, the prevention and control of Chinese rice grasshoppers are crucial due to their significant impact on rice yield and quality. Effective control measures must be implemented to mitigate their damage.

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What Are the Preventive Measures for Grasshoppers?

Grasshoppers can cause significant damage to crops and plants due to their voracious appetite and ability to reproduce rapidly. Implementing preventive measures is essential to manage and reduce the impact of grasshoppers on agriculture and horticulture. Here are some effective strategies for preventing grasshopper infestations:

1. Monitoring and Early Detection

Regular monitoring of fields and gardens is crucial for early detection of grasshopper activity. Look for signs such as chewed leaves and stems, as well as the presence of grasshopper nymphs and adults.

Scouting

Conduct thorough scouting, especially during the early stages of grasshopper development. This helps in identifying hotspots and assessing the severity of the infestation, allowing for timely intervention.

2. Habitat Management

Grasshoppers thrive in certain environments. By managing these habitats, you can reduce their population. Implement practices such as:

  • Weed Control: Remove weeds and tall grasses around fields and gardens to eliminate breeding sites.

  • Crop Rotation: Rotate crops to disrupt the grasshopper life cycle and reduce their food sources.

  • Field Margins: Maintain clean field margins to prevent grasshoppers from migrating into crop areas.

3. Biological Control

Encourage natural predators and use biological control agents to keep grasshopper populations in check. Some effective biological control methods include:

Predators

Introduce or conserve natural predators such as birds, frogs, and beneficial insects (e.g., spiders, beetles) that feed on grasshoppers.

Pathogens

Utilize pathogens like the fungus Metarhizium acridum, which specifically targets grasshoppers and can help reduce their numbers.

4. Chemical Control

In cases of severe infestations, chemical control may be necessary. Use insecticides judiciously and follow these guidelines:

  • Selective Insecticides: Choose insecticides that specifically target grasshoppers to minimize impact on beneficial insects.

  • Timing: Apply insecticides during the early nymph stages when grasshoppers are more vulnerable and before they cause significant damage.

  • Rotation: Rotate insecticides to prevent resistance buildup in grasshopper populations.

5. Cultural Practices

Implementing cultural practices can help deter grasshoppers and protect crops. Some effective practices include:

  • Trap Crops: Plant trap crops (e.g., oats, wheat) around main crops to attract and concentrate grasshoppers, making them easier to control.

  • Intercropping: Use diverse cropping systems to make it harder for grasshoppers to find and feed on their preferred plants.

  • Mulching: Apply mulch to reduce grasshopper egg-laying sites and protect young plants.

Conclusion

Preventing grasshopper infestations requires a combination of monitoring, habitat management, biological control, chemical control, and cultural practices. By implementing these strategies, farmers and gardeners can effectively reduce the impact of grasshoppers on their crops and plants, ensuring healthier and more productive growing seasons.

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