The predacious midge, Aphidoletes aphidimyza (Rondani), is an effective exclusive natural enemy of aphids in greenhouses and field crops. In this study, prey preference of A aphidimyza was determined ...using seven treatments including different stages (third-instar nymphs and adults) of two prey species (Aphis gossypii Glover and Myzus persicae (Sulzer)) based on Manly's (B preference index. Results of experiments consisting of two different preys showed that A aphidimyza larvae consumed A gossypii more than M. persicae, and the third nymphal stage of both species was preferred more, compared with adults. When all four types of prey were studied, Manly's index was 0.379, 0.235, 0.208, and 0.176 for nymphs of A gossypii and M. persicae and adults of A gossypii and M. persicae, respectively. Therefore, the nymphs of both species, as the most preferred prey, were used to study the reproductive performance of the predator in microcosm conditions. The significantly longer adult longevity (female: 7.62 + or - 0.15, male: 7.42 + or - 0.23 d), higher fecundity (93.75 + or - 2.94 offspring per female), and higher intrinsic rate of increase (0.175 + or - 0.009 d.sup.-1 ) of A aphidimyza were obtained, while consuming third-instar nymphs of A gossypii. Finally, this study indicated that third-instar nymphs of A gossypii are the most suitable food for mass rearing of A aphidimyza. Key words: Cecidomyiidae, cotton aphid, Myzus persicae, prey preference, developmental stage
Although the high Arctic archipelago Svalbard is among the best-studied Arctic regions in terms of biodiversity, its aphid fauna is extremely limited. Two endemic species have been described to date, ...and no species of a foreign origin has been registered. Our observation is the first record of the non-native and potentially invasive green-peach aphid species Myzus (Nectarosiphon) persicae (Insecta, Hemiptera, Aphididae), which was collected on the largest island of the archipelago-Spitsbergen. The green-peach aphid was found on three different ornamental plants: Viola tricolor (Violaceae), Dianthus caryophyllus (Pink Kisses) (Caryophyllaceae) and Petunia x hybrida (surfinia) (Solanaceae). The plants were displayed in front of one of the shops in the main street of Longyearbyen, the largest populated settlement of Svalbard. The infected plants came from the only supermarket on the archipelago, which had brought them from the mainland of Norway. Although the aphids (winged and wingless viviparous females and immature ones) were clearly visible on all of the plants (the distinct colonies from few to numerous individuals), the owners were not aware that the plants were infected. Similarly, the supermarket staff who are responsible for the live green plants did not register the presence of aphids on the imported plants. In this context, our results also suggest that a stricter approach to regional biosecurity needs to be considered in order to avoid the risks of further unintentional introductions.
The spotted alfalfa aphid (SAA), Therioaphis trifolii, is a phloem-feeding pest with a complex life history, and it causes a tremendous global loss of crop yields. A large number of previous studies ...focused only on few-generation life tables, whereas multi-generation life tables could explore aphid adaptation processes that are poorly understood. In this study, we investigated the effects of physical characters of alfalfa on SAA growth and development and used life-table parameters to evaluate the transgenerational effects of SAA populations on highly resistant (HA-3) and highly susceptible (Hu) alfalfa cultivars. The results indicated that alfalfa waxy content, anatomical structure of vegetative organs, and density and length of leaf hairs were significantly positively correlated with resistance to the SAA. In terms of the developmental time of total preoviposition period (TPOP), no significant differences were observed between two populations; compared to the HA-3 population, the G2-G8 Hu populations were markedly lower and G9-G10 Hu populations were visibly higher. Meanwhile, the reproductive days, mean longevity, and fecundity (offspring) of the HA-3 population were obviously higher than those of the Hu group after G5. Furthermore, the finite rate of increase (λ) and intrinsic rate of increase (r) of HA-3 were significantly higher than for the Hu population after G7. Meanwhile, the net reproductive rate (Rsub.0) and mean generation time (T) of HA-3 were significantly higher than for the Hu population after G5. On the whole, the SAA had a high survival rate, strong reproductive capacity, long life span, and high population growth parameters on Hu in the early stage, while the SAA had better growth and development on HA-3 in the late stage. The physical characteristics of alfalfa leaves could be used as one of the indicators of aphid resistance. However, the coevolutionary coupling was broken with the gradual adaptation of SAA, which provides an empirical basis for further exploring the mechanisms of alfalfa resistance to aphids and the integrated control of pests.
Control of Rosy Apple Aphid, 2021 Wheeler, C E; Bosch, A K; VanWoerkom, A H ...
Arthropod management tests,
01/2022, Volume:
47, Issue:
1
Journal Article
Control of Woolly Apple Aphid in Apple, 2018 Wise, John C; Wheeler, Celeste E; VanWoerkom, Anthony ...
Arthropod management tests,
01/2020, Volume:
45, Issue:
1
Journal Article
Ultraviolet (UV) radiation directly regulates a multitude of herbivore life processes. in addition to indirectly affecting insect success via changes in plant chemistry and morphogenesis. Here we ...looked at plant and insect (aphid and whitefly) exposure to supplemental UV-A radiation in the glasshouse environment and investigated effects on insect population growth. Glasshouse grown peppers and egg- plants were grown from seed inside cages covered by novel plastic filters, one transparent and the other opaque to UV-A radiation. Importantly, in pepper, the UV-A treated plants contained higher contents of secondary metabolites, leaf soluble carbohydrates, free amino acids and total content of protein. For eggplants, chlorophylls a and b, and carotenoid levels decreased with supplemental UV-A over the entire crop cycle but UV-A exposure did not affect leaf secondary metabolites. However, exposure to supplemental UV-A had a detrimental effect on whitefly development, fecundity and fertility presumably not mediated by plant cues as compounds implied in pest nutrition - proteins and sugars - were unaltered.
PDF
