Anais da Sociedade Entomológica do Brasil (2000) 29, 757-764

Celso Omoto, Everaldo B. Alves and Paulo C. Ribeiro (2000)
Detecção e Monitoramento da Resistência de Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) ao Dicofol
[Detection and monitoring of resistance in Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) to dicofol]
Anais da Sociedade Entomológica do Brasil 29 (4), 757-764
Abstract: A residual bioassay technique was used to characterize the resistance of Brevipalpus phoenicis (Geijskes) to the acaricide dicofol. Different concentrations of dicofol were sprayed on citrus leaf disks with a Potter spray tower. After treatment, each leaf disk was placed on an agar-water solution at the concentration of 2.3% in a petri dish. Adult mites were transferred onto the arena and bioassay dishes were kept at 25±1°C, relative humidity of 70±10% and photoperiod of 14h. The mortality was assessed 24h after mite infestation. The estimated LC₅₀s for susceptible and dicofol-resistant strains were 7.44 µg of dicofol/ml of distilled water [ppm (A.I.)] (95% CI 6.74 - 8.23) and 422.45 ppm (A.I.) (95% CI 369.41 - 482.80), respectively. The resistance ratio derived from LC₅₀s was about 57-fold. Based on this difference, discriminating concentrations between 32 and 100 ppm (A.I.) were defined for monitoring dicofol-resistant B. phoenicis. A survey of different B. phoenicis populations collected from commercial citrus groves in the State of Sao Paulo showed significant differences between populations in relation to their responses to dicofol.
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(original language: Portuguese)
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Database assignments for author(s): Celso Omoto

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Brevipalpus phoenicis	Citrus (genus)	Brazil (south)