BIOECOLOGY AND DEVELOPMENT OF THE CALIFORNIA SHIELD SHIELD (QUADRASPIDIOTUS PERNICIOSUS COMST.) IN UZBEKISTAN

Dangerous coccids are widespread in Uzbekistan. Of these, the californian shield insect is a quarantine pest. It damages many plants. It damages apple, pear, plum, quince, peach, almonds, hawthorn, elm, poplar and others. Diapausing larvae of the first age overwinter, covered with a dark gray or black shield. In spring, it feeds intensely, molts and forms a shield similar to that of an adult female. After the second molt, adult females are formed. After mating, the female spawns larvae of strollers, which spreads along branches and leaves, and can also settle on fruits. It gives rise to the next generation

Determination of spray dates for the control of the first generation of Quadraspidiotus perniciosus in Northern Greece

During 1986-1988 the relationship between catches of San Jose scale (SJS), Quadraspidiotus perniciosus (Comstock), adult males in pheromone traps and crawlers on sticky-tape traps was studied as a basis of SJS crawler control in apple orchards of Northern Greece. Spring male flight began in mid-to late April and crawler emergence occurred in mid-to late May. Crawlers were active for a period of 6-7 weeks until early July. Peak crawler emergence occurred approximately 12 days after the first emergence, or 42 days after the first males were captured on pheromone traps. Because in our 3-year study the crawler emergence occurred 29-31 days or 191-202 day-degrees (base 10.5°C) after the capture of the first male, we conclude that a consistent time-relationship exists between the two events. Two insecticide treatments, one three days after the first crawler appearance and another 10 days later (near peak crawler activity), provided the best control against the first generation of scale.

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

The seasonal flight of San Jose scale (SJS), Quadraspidiotus perniciosus Comstock, males was studied during 1984-1987 in peach and nectarine orchards, under two different climatic conditions in Central Macedonia (Northern Greece), using sex pheromone traps. In late-season regions there were three periods of male flight activity (May, July-August, September – October), while in early-season regions there was also a partial fourth one (mid April-May, mid June-July. August – mid September and late September – early November). In the latter regions these flights can be correlated with the appearance of the scale crawlers during three periods (late May – early July, mid July – August, September – October) and a partial fourth one (November) in milder years, as determined using the sticky-tape trap technique. Pheromone traps and sticky-tape traps can be used for the study of phenology of San Jose scale, under conditions prevailing in Northern Greece.

The occurrence of Encarsia perniciosi in areas of northern Greece as assessed by sex pheromone traps of its host Quadraspidiotus perniciosus

During the 1982-1985 period the aphelinid endoparasite Encarsia perniciosi Tower was captured on synthetic pheromone traps of the San Jose scale (SJS), Quadraspidiotus perniciosus Comstock, in scale-infested insecticide treated and untreated orchards of Central and Western Macedonia (Northern Greece). It has expanded especially near the sites where it had been released, but also in areas 50-100 km from the point of release. The parasite in untreated orchards generally appeared from April to October, while in orchards treated with insecticides it was not caught after mid June. Spring flights of the parasite occurred on almost the same dates as the first captures of the male scale. Subsequent flights of E. perniciosi were not always synchronized with those of the male scale, and after the beginning of June the parasite showed a general decline throughout the remainder of each season. The pheromone of the scale insect acts as a kairomone to the parasite and it can be used in trapping systems in scale-infested orchards for the confirmation of the presence and the dis­tribution of E. perniciosi.

An investigation of San Jos scale (Quadraspidiotus perniciosus) predation by the European earwig (Forficula auricularia)

The European earwig (Forficula auricularia) is a generalist predator of a wide range of insect pests in pipfruit orchards including scale insects Since the development of an integrated fruit production programme that uses selective pesticides and biological control of pests earwigs are now more frequently found in commercial pipfruit orchards San Jos scale (Quadraspidiotus perniciosus SJS) is a diaspid species that is an important insect pest in the main applegrowing regions in New Zealand This study investigated the potential of earwigs to feed on SJS in a nonchoice laboratory trial Individual mature earwigs were placed inside containers with small sections of apple wood infested with mixed age stages of SJS A total of 157 SJS on the apple wood were photographically indentified and marked so that subsequent predation by earwigs over 6 nights could be recorded Predation over this period was 1290 (mean 56) These results indicated that earwigs would potentially feed on scale insects but as they are generalist predators their impact on scale infestations in orchards would depend on scale density and the availability of other prey Very little earwig predation of SJS on fruit was recorded in a similar assessment