In recent years, increasing pesticide resistance in pests has significantly compromised control efficacy, leading to treatment failures and rapid pest resurgence. This not only raises production costs but also intensifies labor demands for farmers. To achieve longer-lasting and more thorough pest management, targeting pest eggs (ovicidal activity) is critical. This article summarizes key insecticides with ovicidal properties and their applications.
Ovicidal Insecticides and Their Mechanisms
1. Pyriproxyfen
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Class: Juvenile hormone analog
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Mode of Action: Stomach/contact toxicity, systemic activity; disrupts metamorphosis and reproduction.
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Target Pests: Lepidoptera (e.g., Spodoptera exigua, Plutella xylostella), Diptera, Homoptera.
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Advantages: Long residual activity; inhibits mosquito/pupae emergence.
2. Spirotetramat
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Class: Tetramic acid derivative
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Mode of Action: Bidirectional systemic translocation; inhibits lipid synthesis.
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Target Pests: Scales, aphids, whiteflies, thrips.
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Advantages: Excellent against concealed pests (e.g., armored scales).
3. Pyridaben
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Class: Mitochondrial electron transport inhibitor (METI)
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Target Pests: Spider mites, whitefly eggs.
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Limitation: High resistance risk.
4. Buprofezin
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Class: Chitin synthesis inhibitor
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Mode of Action: Suppresses oviposition and egg hatching.
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Target Pests: Scales, leafhoppers.
5. Etoxazole
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Class: Diphenyloxazoline
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Target Pests: Mite eggs/immature stages; sterilizes adult females.
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Application Timing: Early infestation critical.
6. Spirodiclofen
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Class: Tetronic acid derivative
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Advantages: High ovicidal efficacy; active against juvenile mites.
7. Cyetpyrafen
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Class: Pyrazole acaricide
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Target Pests: All mite life stages (egg to adult).
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Advantages: Temperature-stable; fast action.
8. Bifenazate
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Class: Carbazate acaricide
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Target Pests: Two-spotted spider mites (Tetranychus urticae).
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Advantages: Rapid knockdown; IPM-compatible.
9. Cartap
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Class: Nereistoxin analog
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Mode of Action: Neurotoxin (paralysis).
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Target Pests: Rice stem borers, vegetable lepidopterans.
10. Fenbutatin oxide
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Class: Organotin acaricide
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Limitation: Phytotoxic to citrus during flowering.
Other Notable Ovicidal Agents
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Hexythiazox: Selective against mite eggs (ineffective on adults).
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Cyflumetofen: Controls all mite stages; safe to beneficials.
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Flubendiamide: Ryanodine receptor modulator; potent egg killer.
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Methomyl: Carbamate with ovicidal effects; resistance-breaking.
Conclusion
Integrating ovicidal insecticides into pest management programs is essential to delay resistance and improve long-term control. Key strategies include:
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Rotation: Alternate chemistries (e.g., IGRs, METIs).
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Timing: Apply during egg-laying/early infestation.
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Combination: Mix with adulticides (e.g., abamectin + pyriproxyfen).
For optimal results, farmers should prioritize mode-of-action diversity and resistance monitoring.
