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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #102319
Title: CHEMICAL APPLICATION EQUIPMENT FOR IMPROVED DEPOSITION IN COTTON

Author
item Sumner, Harold
item HERZOG, GARY - UNIV. OF GEORGIA
item SUMNER, PAUL - UNIV. OF GEORGIA
item BADER, MIKE - UNIV. OF GEORGIA
item MULLINIX, BEN - UNIV. OF GEORGIA

Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Pesticides applied to control cotton insects, such as aphids, spider mites, and whiteflies that feed on the underside of leaves or down into the plant canopy, need to be deposited where insects feed. Air-assist electrostatic and air-assisted hydraulic sprayers developed in recent years sto improve pesticide penetration and coverage within the plant canopy need to be evaluated to determine if they place more pesticide within the plant canopy and on underside of leaves better than conventional-hydraulic nozzle sprayers. This study compared within canopy penetration and leaf coverage in cotton plants of spray materials applied by five different sprayers. Spot diameters generated by all five sprayers collected on water-sensitive cards were larger on leaf topside than on leaf underside, coverage was higher on leaf topside than on leaf underside, and higher in the top than the middle of the plant canopy. Hydraulic nozzle sprayers deposited more spray material on leaves where the nozzles directed the spray solution. The air-assisted sprayer deposited spray material throughout the plant canopy and had better coverage on the underside of leaves. Sprayer methods influence spray penetration and leaf coverage in cotton and can be selected to provide improved application for control of specific insect pests based on the plant part where the insects feed.

Technical Abstract: Air-assist electrostatic and air-assisted sprayers developed in recent years need to be evaluated to determine their deposition efficacy within the plant canopy. This study was conducted to determine and compare within canopy deposition of spray materials in cotton plants sprayed with conventional hydraulic nozzles, air-assisted, and electrostatic sprayers. Water sensitive paper, residue washed from leaves, and fluorescent dye collected on strings were methods used to determine spray deposition and leaf coverage. Spot diameters collected on water sensitive paper for all five sprayers were larger and coverage was higher on the topside of leaves than on the underside of leaves in the top of the plant canopy. The air- assisted sprayer had better coverage on the underside of leaves than other sprayers and also provided good coverage on the topside of leaves. The hydraulic nozzle sprayer deposited more spray material, measured by the leaf wash method, on leaves at locations where the nozzles were directed. The air-assisted sprayer deposited spray material throughout the plant and on both leaf surfaces. Total net fluorescence on collector strings decreased from the top to the bottom of plants and was high in locations where hydraulic nozzles were directed. Sprayer methods influenced deposition and coverage in cotton and can be selected to provide improved application in the plant canopy where optimum coverage is needed.