Publication Date: 2019.
Predator-prey interactions are not static, but spatially and temporally dynamic. In addition to the climatic conditions and the prey density, the dynamics of predator populations may be influenced by the suitability of their diet. Therefore, to better understand aphid predator-prey relationships within food webs, it is necessary to know how their life history traits are affected by diet quality. In this research, under laboratory conditions, the suitability of the two most abundant aphid species in citrus agroecosystems of the Western Mediterranean basin, Aphis gossypii and A. spiraecola were evaluated for two of their principle natural enemies, the coccinellid predators Scymnus subvillosus and S. interruptus. The intrinsic rate of increase of S. subvillosus was found to be higher than that of S. interruptus regardless of the type of prey consumed. Some biological parameters of S. interruptus were lower when they were exclusively fed A. spiraecola; as opposed to when only fed A. gossypii. These differences were not found with S. subvillosus. When a mixed diet of both aphids was offered, the fitness of both predators was higher than when they were each fed only a single aphid species. These laboratory observations were further confirmed under field conditions, wherein S. subvillosus abundance was greater in those colonies where A. spiraecola was predominant. On the other hand both, S. subvillosus and S. interruptus were found equally in A. gossypii colonies. Implications of these results for the biological control of aphids in this crop are discussed.
Author affiliation: Bouvet, Juan Pedro. INTA. Estación Experimental Agropecuaria Concordia; Argentina. Instituto Valenciano de Investigaciones Agrarias (IVIA). Centro de Protección Vegetal y Biotecnología; España
Author affiliation: Urbaneja, Alberto. Instituto Valenciano de Investigaciones Agrarias (IVIA). Centro de Protección Vegetal y Biotecnología; España
Author affiliation: Monzó, César. Instituto Valenciano de Investigaciones Agrarias (IVIA). Centro de Protección Vegetal y Biotecnología; España
Repository: INTA Digital (INTA). Instituto Nacional de Tecnología Agropecuaria
Publication Date: 2012.
Densities of aphids (Aphis gossypii and A. spiraecola) and mummified aphids at different phenological stages of a blueberry crop were estimated for the purpose of developing sampling plans. Our data set comprised 99 samples taken during the period 2006–2008 in four fields in Buenos Aires Province, Argentina. Estimation of population density based on the proportion of sample units infested by individuals was investigated. We also calculated the minimum number of sample units to estimate the density of individuals on buds and buds þ flowers using enumerative sampling. The relative precision of both methods was compared. Moreover, an enumerative sequential sampling protocol was developed. The presence–absence sampling plan gave density estimates with large variances (as measured by confidence intervals and large standard errors). The aggregation of mummies was similar on buds and buds þ flowers, so the required number of sample units for density estimates was the same. Relative precision of estimates was much lower for the presence–absence sampling than the enumerative sampling, even at intermediate densities. An enumerative sequential plan would be the most appropriate and useful method in management plans for aphids and mummified aphids in blueberries.
Author affiliation: Rocca, Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina
Author affiliation: Greco, Nancy Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina
Repository: CONICET Digital (CONICET). Consejo Nacional de Investigaciones Científicas y Técnicas