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CONTROL OF MEALYBUGS ON COLEUS, 2001

CONTROL OF MEALYBUGS ON COLEUS, 2001 (G32) COLEUS: Solenostemon scutellarioides (L.) Codd M. L. Casey, D. G. Nielsen, R. K. Lindquist, and R. A. J. Taylor Department of Entomology OARDC/OSU Wooster, OH 44691 Phone: (330) 263-3961 Fax: (330) 263-3685 E-mail: rajt@osu.edu Mealybug: Planococcus spp., Pseudococcus spp., Maconellicoccus spp. One plug flat of mixed bedding plant coleus was transplanted to 4-inch pots filled with Metro-mix 366 Coir. Pots were arranged in an RCB design with six replications and 10 treatments. Plants were infested in situ by placing three adult female mealybugs on the primary stem of each plant with a small paint brush. When egg production and hatch by at least one female was observed on plants, pretreatment samples were taken, and applications were made (8 Jun, Day 0). A C0 pressurized backpack sprayer with a six TXVS cone jet nozzles on an 18-inch wand was used to make applications at 30 psi. Seven combinations of Flagship 25 WG and Endeavor and two of Marathon II were made over a 6-wk period. Greenhouse temperature and humidity and sky conditions were recorded at each application (8 Jun [Day 0], 31°C, 12% RH, sunny skies; 22 Jun [Day 14] 25°C, 44% RH, overcast; 6 Jul [Day 28] 28°C, 28%RH, overcast; 20 Jul [Day 42], 35°C, 34% RH, sunny). All replicates in a treatment were sprayed at the same time and the pots returned to the bench to be placed back in their original positions. A timer was used to standardize application so that each 6-plant plot was sprayed for 17 s (2-3 s/plant). Samples were taken weekly following the first application. The number of live mealybugs (all stages) on a contiguous 3-inch length of stem was counted to evaluate treatment effects. When large healthy mealybug masses were encountered, they were given a score of 50 to facilitate sampling. Mealybug control on treated plants was adequate through the first 6 wk after treatment. Dead mealybug crawlers were observed on foliage of plants in most treatments within 72 h of treatment. Reinfestation pressure within the greenhouse compartment was high. At least one live mealybug crawler could be found on most plants throughout the 8-wk study. However, mealybug reproduction was not observed on any treated plant through Week 6. All treatments reduced the total number of live mealybugs by at least 60%, despite relatively high reinfestation pressure. Most treatment combinations were significantly better than the check, however, Flagship applied at 14-day intervals, Flagship followed by Endeavor and Marathon was significanlty different from the check on all dates up to the end of the experiment on Day 49. Outdoor and greenhouse temperatures were significantly higher during the last 4-wk treatment period than the first 4 wk. This could have contributed to the higher mealybug reproductive rates that resulted in the treatment failures observed on the last sample date. The mealybug population on two check plants increased beyond plant tolerance level and died during the week of 31 Jul when the experiment was terminated. No phytotoxicity was observed. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Arthropod Management Tests Oxford University Press

CONTROL OF MEALYBUGS ON COLEUS, 2001

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Oxford University Press
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10.1093/amt/27.1.G32
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Abstract

(G32) COLEUS: Solenostemon scutellarioides (L.) Codd M. L. Casey, D. G. Nielsen, R. K. Lindquist, and R. A. J. Taylor Department of Entomology OARDC/OSU Wooster, OH 44691 Phone: (330) 263-3961 Fax: (330) 263-3685 E-mail: rajt@osu.edu Mealybug: Planococcus spp., Pseudococcus spp., Maconellicoccus spp. One plug flat of mixed bedding plant coleus was transplanted to 4-inch pots filled with Metro-mix 366 Coir. Pots were arranged in an RCB design with six replications and 10 treatments. Plants were infested in situ by placing three adult female mealybugs on the primary stem of each plant with a small paint brush. When egg production and hatch by at least one female was observed on plants, pretreatment samples were taken, and applications were made (8 Jun, Day 0). A C0 pressurized backpack sprayer with a six TXVS cone jet nozzles on an 18-inch wand was used to make applications at 30 psi. Seven combinations of Flagship 25 WG and Endeavor and two of Marathon II were made over a 6-wk period. Greenhouse temperature and humidity and sky conditions were recorded at each application (8 Jun [Day 0], 31°C, 12% RH, sunny skies; 22 Jun [Day 14] 25°C, 44% RH, overcast; 6 Jul [Day 28] 28°C, 28%RH, overcast; 20 Jul [Day 42], 35°C, 34% RH, sunny). All replicates in a treatment were sprayed at the same time and the pots returned to the bench to be placed back in their original positions. A timer was used to standardize application so that each 6-plant plot was sprayed for 17 s (2-3 s/plant). Samples were taken weekly following the first application. The number of live mealybugs (all stages) on a contiguous 3-inch length of stem was counted to evaluate treatment effects. When large healthy mealybug masses were encountered, they were given a score of 50 to facilitate sampling. Mealybug control on treated plants was adequate through the first 6 wk after treatment. Dead mealybug crawlers were observed on foliage of plants in most treatments within 72 h of treatment. Reinfestation pressure within the greenhouse compartment was high. At least one live mealybug crawler could be found on most plants throughout the 8-wk study. However, mealybug reproduction was not observed on any treated plant through Week 6. All treatments reduced the total number of live mealybugs by at least 60%, despite relatively high reinfestation pressure. Most treatment combinations were significantly better than the check, however, Flagship applied at 14-day intervals, Flagship followed by Endeavor and Marathon was significanlty different from the check on all dates up to the end of the experiment on Day 49. Outdoor and greenhouse temperatures were significantly higher during the last 4-wk treatment period than the first 4 wk. This could have contributed to the higher mealybug reproductive rates that resulted in the treatment failures observed on the last sample date. The mealybug population on two check plants increased beyond plant tolerance level and died during the week of 31 Jul when the experiment was terminated. No phytotoxicity was observed.

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Arthropod Management Tests – Oxford University Press

Published: Jan 1, 2002

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