Author
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Zettler, James |
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Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/17/2002 Publication Date: N/A Citation: N/A Interpretive Summary: The pink hibiscus mealybug attacks more than 200 agricultural commodities, forestry products and nursery stock. It was recently introduced into California near agricultural areas in El Centra and Calixico and poses a serious threat to California agriculture. The preferred method of control for commodities infested with mealybugs is fumigation with methyl bromide because of its ease of application, fast action, and cost. The approved fumigation protocol for mealybugs is given in the APHIS Treatment Schedule T-104-a-2 which involves fumigating the infested commodity with a methyl bromide dose of 48 mg/L for 2 hours when the temperature of the commodity is between 21 and 25C. However, this treatment has never been evaluated against the pink hibiscus mealybug. Thus, we tested the effectiveness of methyl bromide against different life stages of this insect and determined that crawlers, nymphs and female adults were the most tolerant. Confirmatory tests using the approved APHIS treatment schedule target dose of 48 mg/L showed that methyl bromide at this dose rate caused complete mortality of all life stages. Thus, we conclude that the APHIS treatment schedule for mealybugs will provide quarantine security against pink hibiscus mealybug. Technical Abstract: Eggs, crawlers, early nymphs, late nymphs, and adults of the pink hibiscus mealybug, Maconellicoccus hirsutus (Green), were tested for their susceptibility to methyl bromide in 2 hr laboratory fumigations at ambient conditions (25 C, 95% RH). Dose response tests indicated that the egg was the most susceptible life stage with an LC99 of 20.2 mg/L. Adults, early nymphs, late nymphs, and crawlers were equally susceptible with LC99s of 35.1, 36.9, 37.6, and 38.9 mg/L, respectively. Confirmatory tests showed that a dose of 48 mg/L methyl bromide, the USDA-Animal Plant Health Inspection Service treatment dose schedule for mealybugs at 21 to 26 C, produced 100% mortality of all life stages. We conclude that the methyl bromide treatment schedule for mealybugs will provide quarantine security for Maconellicoccus hirsutus infesting commodities for export or import. |
