|Taylor, Kathryn - UNIVERSITY OF GEORGIA|
Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 15, 2004
Publication Date: October 1, 2004
Citation: Reilly, C.C., Taylor, K.C., Hotchkiss, M.W. 2004. A comparison of airblast and air assisted rotary atomizer spray technologies in peach production. HortTechnology. v.14(4). p.555-559. Interpretive Summary: Existing airblast sprayer technology used in the southeastern United States peach industry was compared to new, emerging air-assisted rotary atomizer (AARA), low volume spray technology. The comparison was conducted in a six-year-old Sunprince peach orchard for the 2000 and 2001 growing seasons. Fungicides and insecticides were applied using both sprayers throughout the two seasons. The AARA sprayer applied 80% of the normal dose of the pesticides and used one half the amount of water at a ground speed of 8 km per hr 5 mph, treating two full rows as compared to the airblast sprayer traveling at 3.2 km per hr and treating one row. Insect damage, blemish, peach scab and brown rot were rated just prior to harvest. The AARA technology was superior in terms of reduced pesticide application and drift, giving similar to acceptable disease and insect control. The obvious advantages of AARA technology are reduced volume per hectare, reduced sprayer refill times, reduced spray time per hectare (9.1 min per ha for the AARA sprayer versus 41.2 min per ha for the airblast), and reduced overall cost for equipment, fuel and labor. Because only alternate middles are traversed by the sprayer, less orchard floor compaction occurs and fewer fruit are bumped or knocked off as limbs sag when fruit mature.
Technical Abstract: Pesticide application with a commercial airblast sprayer was compared to that of an air-assisted rotary atomizer, low volume sprayer in a 16.2 hectare, 6-year-old, Sunprince peach orchard. Early season petal fall and shuck split applications and standard cover sprays using phosmet, sulfur, propiconazole, chlorothalonil, azoxystrobin and captan employed the two technologies. Airblast sprays (467.6 liter per ha) were applied at 3.2 km per hr at 100% of the recommended pesticide rate while air assisted rotary atomizer sprays (233.8 liter per ha) were at 8 km per hr and at 80% of the rate. Eighty ripe fruit, picked from each treatment in each of four blocks, were rated for scab, brown rot, insect damage (cat facing) and blemishes. Scab and blemish ratings indicated a difference between the two application technology treatments. Spray coverage was quantitatively evaluated in two ways: dye (Rhodamine B) and residue of phosmet. Leaf rinses or residue detection on trees of the treated row from each method indicated equivalent coverage for each application method. Phosmet residue was reduced 59% one row away from the treated row and 93% in the fifth row from the treated row by the air assisted rotary atomizer sprayer compared to airblast sprayer.