Revista de la Sociedad Entomológica Argentina
Print version ISSN 0373-5680
LOPEZ GARCIA, Guillermo P.. Population development of Diaspidiotus perniciosus (Hemiptera: Diaspididae) in apple orchards in San Carlos, Mendoza, Argentina. Rev. Soc. Entomol. Argent. [online]. 2011, vol.70, n.3-4, pp. 277-286. ISSN 0373-5680.
The bionomy of Diaspidiotus perniciosus Comstock ("San Jose scale") was studied in an apple orchard of the "Red Delicious" variety in San Carlos, Mendoza-Argentina during the cropping seasons 2007-2008 and 2008-2009. The number of generations per year was determined and the population fluctuation patterns, associated with thermal integral to the species in this region, were studied. D. perniciosus has two generations that overlap the crop cycle, while nymphs (N1 and N2) of the third generation will develop until the end of the summer, going into quiescence in winter. The development of D. perniciosus in the San Carlos-Mendoza area matches that of this species in the orchard cropping area of central Chile in the number of generations and the period of winter dormancy. Quiescent populations in Chile are composed predominantly of first instar nymphs (N1), while in San Carlos, Mendoza, quiescent populations are composed mainly of second instar nymphs (N2). The similarities between the two groups are probably due to similarities in latitude, climate and host species. The economic impact of D. perniciosus in the study area is critical during December and January, due the high levels of damage to fruit and leaves, displaying this time period as particularly sensitive for implementing phytosanitary control measures. Therefore, pest control measures should be based on the maximum population of N1 that occurs at 600-650 Day-Degrees (DD) in December and at 1170-1270 DD in January. In seasons in which the population density of the pest turns especially high, additional control measures could be built at 1800-2000 DD in April. The results of these studies offer a predictive tool to be included in D. perniciosus control strategies to be applied in San Carlos-Mendoza orchard growing area in order to ensure the proper management of the pest in the context of sustainable food production.
Keywords : Diaspidiotus perniciosus; Development; Population dynamics; Malus sylvestris.