Orchard experiments were conducted during 1967-68 to determine the proper dosage, timing, and selection of acaricides in early-season treatments for control of panonychus ulmi (Koch) in apple orchards. Petroleum oil spray was more effective in killing over- wintering eggs as the interval between oil application and egg hatch decreased. One gallon of Humble 70-second viscosity oil applied at the tight-cluster or pink stage of fruit-bud development was more effective than 2 gal- Ions applied at the dormant or green-tip stage. Humble 60- or 70-second viscosity oil, Morestan® (6-methyl-2,3- quinoxalinedithiol cyclic S,S-dithiocarbonate), TH 367-1 (2-fluorethyl 4-biphenylylacetate), and demeton + tetra- difon were the more effective acaricides when used in only 1 preblossom application. Demeton was more effective than dimethoate as an early-season acaricide. As 1 application, demeton or di methoate were more effective when applied at the petal fall stage than at the pink-bud stage. Dimethoate ap plied at the pink-bud stage at the rate of 1 ½ pint per 100 gallons of water gave poor early-season mite control. However, when the dosage was halved and applied at the pink and petal-fall stage, commercial control through June resulted. As 2 early-season applications, demeton or dimethoate were more effective when applied at pink and petal-fall stages than at petal-fall and 1st cover.
Document Type: Research Article
Publication date: October 1, 1969
More about this publication?
Entomological Society of America journals will no longer be available via ingentaconnect from February, 1, 2015. Please contact the publisher at firstname.lastname@example.org (USA) or email@example.com (UK and rest of world) for information on how to continue access to these titles.