Ornamental Plants
Annual Reports and Research Reviews 2002

Special Circular 189

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

Charles R. Krause, Richard C. Derksen, LeonaE. Horst, Ross D. Brazee, Michael G. Klein, and MichaelE. Reding, U.S. Department of Agriculture, Agricultural Research Service, Application Technology Research Unit, Ohio Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, Ohio; Randall Zondag, Ohio State University Extension, Lake County.

Figure 1. Dedicated nursery plots consisting of six crabapple replication rows with four treatments per replication each were planted.

Figure 2. The axial flow, airblast sprayer delivers a treatment to one of the replications.

Materials and Methods

Plant Materials

Dedicated nursery plots consisting of six crabapple replication rows with four treatments per replication each were planted (Figure 1). A replication consisted of seven, two-year-old crabapple whips of each cultivar — Malus spp. cv. Candied Apple and cv. Red Jade — for a total of 14 trees per replication. Barrier rows were also planted between crabapple treatment rows in all production nurseries.

Treatments

Treatments were randomized in each of six rows as follows:

• Axial flow, airblast sprayer with conventional high-volume nozzle delivering 300 psi, traveling at 4 mph.
• Axial flow, airblast sprayer with air induction nozzles delivering 120 psi traveling at 4 mph.
• Experimental air curtain sprayer or cross-flow fan sprayer with air induction nozzles delivering 120 psi at 4 mph.
• Unsprayed control.

Spray treatments were begun in May 2001. Figure 2 shows the axial flow, airblast sprayer delivering a treatment to one of the replications.