Problems in evaluating control of San Jose scale with spray chemicals

Abstract

Problems of evaluating chemical control of San Jose scale are discussed on the basis of experiments in deciduous fruit orchards. Methods are described for sampling and counting scales for mor tality determinations and for measuring the resurgence of a popu lation after it has been reduced. The methods used did not show conclusively any differences in performance among a number of the more effective insecticides used with oil in dormant or spring sprays. The methods were ade quate to show that scale populations on peach trees do not increase as much in the growing season when trees are sprayed in May as when they are sprayed during fall or winter. On lightly infested peach trees sprayed in the dormant season or in May, the survivor progenies increased faster during the growing season than they did on trees that were more heavily infested when sprayed. The effects of variation in initial pest density on control were mini mized by using pretreatment counts with the annual twig-count method. This method measured degree of population resurgence after treatment but did not show how numbers of survivors, effects of natural enemies, and other environmental factors acted together to produce the results observed. Sequences of samples for mortality determinations indicated trends in population change after treat ment.

Pesticide residues and greedy scale control on kiwifruit

“…Armoured scales can take from 3 to 7 weeks after mineral oil application before they fully darken and dry so as to become recognisably dead (Stafford & Summers 1963). Insecticideinduced death shows more rapidly (Ferguson pers.…”

Phenology of the San Jose Scale (Homoptera: Diaspididae)

“…San Jose scale, Quadraspidiotus perniciosus (Comstock), is a key pest in most deciduous fruit orchards of western North America (Gentile and Summers 1958;Stafford and Summers 1963;Anthon 1967;Downing and Logan 1977;and Rice et al 1979). It has been a pest since first introduced from China on flowering peach early in the 1870's (Gentile and Summers 1958;Flanders 1960).…”

“…Control of San Jose scale in deciduous fruit orchards of western North America is usually achieved with dormant oil sprays, or spring and summer applications of organophosphates to control crawlers (Anthon 1960;Stafford and Summers 1963;Downing and Logan 1977;Westigard 1977Westigard , 1979Rice et al 1979). Dormant oil usually controls light infestations, but heavy encrustations often require additional applications to control crawlers (Downing and Logan 1977).…”

Suppression of white mango scale, Aulacaspis tubercularis (Hemiptera: Diaspididae) on mango trees in El-Beheira Governorate,‎ Egypt.

“…The reduction of the inspection of insect numbers was expressed as reduction percentages which have been calculated according to (Stafford and Summers, 1963). Statistical analysis of variance and LSD value for comparing the mean effects of each treatment were adopted according to (Snedecor, 1970).…”