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- Phenology, population trends and natural enemy complex of Illinoia liriodendri in SpainPublication . Meseguer, Roberto; Madeira, Filipe; Kavallieratos, Nickolas G.; Pons, XavierIllinoia liriodendri (Monell) (Hemiptera: Aphididae) is an Eastern North American native aphid species that infests ornamental tulip trees, Liriodendron tulipifera L. (Magnoliales: Magnoliaceae), in many localities of Spain and southern Europe. This is a comprehensive three-year study on the biology and ecology of the aphid, where its life cycle, phenology, population dynamic trends, comfort damages, natural enemy complex and its potential to control aphid populations have been investigated for the first time in Europe. The monoecic-holocyclic annual cycle of I. liriodendri has been demonstrated. The highest infestation levels were recorded in May and June, but infestation severity varied among localities. No clear trend regarding the effect of planting site (pit vs. ground) on aphid abundance was observed. A strong positive relationship between the aphid infestation severity and the honeydew dripping was recorded. There was a wide complex of natural enemies associated with the aphid. Coccinellidae were the most abundant predators (< 95%) and showed a positive numerical response to the aphid infestation. Several parasitoid species (mainly Hymenoptera: Aphidiinae and Hymenoptera: Aphelinidae) were found parasitizing I. liriodendri in Spain. The role of natural enemies as agents for controlling the aphid populations is discussed.
- Contribution of surrounding flowering plants to reduce abundance of Aphis nerii (Hemiptera: Aphididae) on Oleanders (Nerium oleander L.)Publication . Madeira, Filipe; Lumbierres, Belén; Pons, XavierOleander is very frequently planted as an ornamental shrub in urban areas of the Mediterranean. Its most common pest is the aphid Aphis nerii, and heavy infestations produce aesthetic damage and disturbances to the citizens, and they are frequently sprayed with insecticides in order to reduce the population density. One alternative method is conservation biological control which is enhanced by the provisioning of alternative food, refuges, and reproduction sites. In this study, the usefulness of four flowering service plants (Lobularia maritima, Calendula officinalis, Coreopsis grandiflora, and Achillea millefolium) is evaluated for aphid infestation levels and aphid natural enemy abundances. Aphid levels were consistently lower in oleander plots surrounded by service plants. Natural enemy abundances tended to be higher in plots surrounded by service plants, but significant differences could not be found until the fourth year of the study, when more lacewings, total predators, and mummies were higher in plots surrounded by service plants. On these plots, hoverflies, ladybeetles, and lacewings were the most common predators. Paragus sp. and Hippodamia variegata were the prevalent hoverfly and ladybeetle species, respectively. The potential toxicity effect on the prevalence of natural enemy species is discussed. On service plants, significantly more hoverflies were recorded on L. maritima than on C. officinalis and C. grandiflora, and more true bugs were recorded on C. officinalis and A. millefolium than on L. maritima or C. grandiflora. Our results suggest that planting service plants (such as sweet alyssum, marigold, or yarrow) surrounding oleanders can improve conservation biological control by enhancing the abundance of aphid natural enemies and thus a reduction of the abundance of A. nerii.