Submitted to: Extension Circular
Publication Type: Experiment Station
Publication Acceptance Date: December 1, 2002
Publication Date: January 20, 2003
Citation: Anderson, B.A., Reding, M.E., Klein, M.G., Krause, C.R. 2003. IR-4 Ornamental Trials Conducted by USDA-ARS in Ohio: 2002. Extension Circular. 189:85-88. Technical Abstract: Interregional Research Project No. 4 (IR-4) is a program that addresses the shortage of pest control products registered for ornamental crops by funding pesticide trials to attain the needed data for registration by the EPA. The Application Technology Research Unit (ATRU), USDA/ARS, in Wooster, conducts approximately 60 IR-4 ornamental trials per year. During the 2002 growing season, 64 trials were conducted in Wooster and Lake County. Tests included fungicides, insecticides and herbicides on greenhouse, field container and field grown herbaceous perennials and woody trees and shrubs. Each test included untreated control plants and three pesticide treatment rates: 1X (the rate recommended by the manufacturer), 2X and 4X. Plants were rated for phytotoxicity and efficacy. Both formulations of the herbicide Flumioxazin caused chlorosis and necrosis on the two plant species, Duetzia gracilis and Phalaris arundinacea (Ribbon-grass). The fungicide Bacillus subtilis caused necrotic leaf margins and spotting on Verbena canadensis and Impatiens hawkeri. Acibenzolar reduced flowering after the third and fourth treatments on Impatiens balsamina. Efficacy data was not obtained in the insecticide container tests or the rhododendron field tests due to poor survival of grubs in control plants. The naturally infested field of hemlocks showed stunting from EC larval feeding (Fig 2), and yielded efficacy data for the Trichlorfon (Dylox) drench applications. The three Dylox treatment rates all had significantly fewer grub numbers than the untreated trees (the average number of grubs was 3.2 and 1.1 in the untreated controls and 1X rate of Dylox, respectively).