Phenology of the San Jose Scale (Homoptera: Diaspididae) in New York State Apple Orchards,

Abstract

Can. Ent. 115: 717-722 (1983) Pheromone trapping studies from 1979 to 1981 showed that there were two periods of San Jose scale, Quadraspidiotus perniciosus (Comstock), male flight activity annually in western New York apple orchards. Spring flight, which resulted from overwintering black caps, began at ca. 94-140 degree-days (base rO°C from 1 March) and occurred during bloom in the apple varieties studied. First generation crawlers emerged at ca. 360 degree-days. Second generation crawlers emerged at ca. 890 degree-days and were active throughout September. Regression analyses showed a logistic relationship between crawler density and fruit infestation, and inverse linear relationships between pheromone trap catches and San Jose scale infestation levels within trees.

Airborne Dispersal of San Jose Scale, Quadraspidiotus perniciosus (Comstock) (Homoptera: Diaspididae), Crawlers Infesting Apple1

“…This work supported the preliminary study (Mague 1982) that had suggested that airborne transport of SJS crawlers was important in dispersal to new sites of infestation. The low numbers of crawlers dispersing between trees, relative to the higher densities dispersing within the canopy, indicated that aerial movements between trees was not an important factor affecting fruit (Cornwall 1960, Greathead 1972) on other species of Coccoidea in cacao and sugarcane, where aerial dispersal of crawlers was inversely related to height.…”

“…However, a behavioral component could not be discounted, since SJS crawlers tend to migrate upward on a vertical plane and their dispersal range is temperature-dependent (Gentile and Summers 1958). In the field, SJS crawlers were most active before 1200 h on sunny days (Mague 1982). Therefore a light-or temperature-related response, which has been documented in other diaspidids (Beardsley and Gonzalez 1975), may at least partially explain the higher crawler densities in the SE quadrant and at the 3.5-rn height.…”

“…A preliminary field study (Mague 1982) demonstrated that there was no significant reduction in the percentage of SJS-infested fruit at harvest when crawlers walking over the bark had been mechanically excluded from access to the fruit. This indicated that aerial dispersal of crawlers was an important factor contributing to crop infestation by the SJS and may have functioned in population spread within and between hosts.…”

Flight of San Jose scale, Quadraspidiotus perniciosus males and time of crawler appearance in orchards of northern Greece

“…Seasonal crawler activity was measured on stickytape traps (Mague andReissig 1983, Kyparissoudas et al 1987) in four trees from mid-May (approximately twenty-five days after the onset of male flight) until mid-December. Four such traps were placed on branches 3-4cm in diameter in each of the four trees; the traps were checked daily until the first appearance of the crawlers and then at one week intervals.…”

“…Male phenology has been determined by pheromone trapping studies (Rice andJones 1977, Rice andHoyt 1980). In the last years, sticky electrical-tape traps, a more sensitive, effective and practical technique, were used for monitoring seasonal activity and relative abundance of crawlers in commercial orchards (Mague and Reissig 1983). These techniques provide an effective and yet economic method of sampling this Received for publication May 2, 1988. scale and were used recently for the study of the SJS phenology in apple orchards (Mague and Reissig 1983).…”