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ARS Home » Midwest Area » Wooster, Ohio » Application Technology Research » Research » Publications at this Location » Publication #141983

Title: The Effects of Sprayer Configuration on Efficacy for the Control of Scab on Crabapple

item Krause, Charles
item Derksen, Richard
item Horst, Leona
item Brazee, Ross
item Klein, Michael
item Reding, Michael - Mike

Submitted to: Extension Circular
Publication Type: Experiment Station
Publication Acceptance Date: 12/1/2002
Publication Date: 1/21/2003
Citation: Krause, C.R., Derksen, R.C., Horst, L., Zondag, R., Brazee, R.D., Klein, M.G., Reding, M.E. 2003. The Effects of Sprayer Configuration on Efficacy for the Control of Scab on Crabapple. Extension Circular. 189:65-68

Interpretive Summary:

Technical Abstract: Direct evaluation and correlation of fungicide coverage, and the amount of apple scab disease were investigated relative to the effects of sprayer/nozzle. Dedicated nursery plots consisted of 6 crabapple treatment rows with 4 replications each. Crabapple whips of each cultivar, Malus spp. cv. `Candied Apple' and cv. `Red Jade' were used with barrier rows. Treatments consisted of: an axial flow, airblast sprayer with conventional-high volume nozzle delivering 300 psi; an axial flow, airblast sprayer applied treatments of mankocide fungicide spray with air induction nozzles delivering 120 psi; an experimental air curtain sprayer or cross-flow fan sprayer with air induction nozzles delivering 120 psi; and an unsprayed control. Leaf analysis was performed using a cold field emission scanning electron microscope and a variable pressure scanning electron microscope, both equipped with energy dispersive x-ray analyzers to directly visualize and identify the pathogens and morphologically and chemically characterize any fungicide present. Disease evaluation was made using a Horsfall-Barrett Scale read each month during spray treatments. A portable meteorological station monitored weather conditions within the experimental plot. Fungicide coverage was measured with EBA, but low disease pressure did not permit quantifying differences in efficacy.