In June 2007, the Asian longhorned beetle Anoplophora glabripennis (Motschulsky) was found at Corbetta, in Lombardy, 23 km west of Milan, Italy. The invasive exotic pest was observed in four host trees, one sycamore maple Acer pseudoplatanus L. and three silver birches Betula pendula Rothmahler. During summer 2007, 20 living and 107 dead A. glabripennis beetles were collected on or around the infested trees. The dissection of the infested material showed that 287 beetles emerged from the trees during previous years and 158 living larvae of varied ages were still developing in April, 2008. Fortunately, it appears that predation by birds on early stage larvae developing under the bark, played a major role in limiting the developing pest population. A. glabripennis is native to China and Korea where it is considered as a serious pest of many deciduous trees including maples, poplars, and willows. During the last decade, it was accidentally introduced into the USA, Canada, Austria, Germany and France in wood packaging material of goods imported from China. The current discovery in Italy is the first record of the Asian pest in this country.

No abstract

No abstract

Diuraphis noxia, the Russian wheat aphid, has become a major pest of wheat and barley since first being detected in the western USA in 1986. However, it is rarely a pest in Eurasia, its area of origin, and research has shown that natural enemies can limit its abundance there. Among the most important of natural enemies of D. noxia in Eurasia are parasitoids in the genus Aphelinus. Here we report results on host specificity of ten populations of seven species from two species complexes in the genus Aphelinus. Host specificity was not related to host plant species or the phylogenetic relatedness of the aphids or the parasitoids. While some species had very broad host ranges and others had intermediate host ranges, Aphelinus hordei had a very narrow host range, being restricted primarily to species in the genus Diuraphis, and especially D. noxia. We also report the results of experiments on the mechanisms of this host specificity. Most of the host specificity of A. hordei can be explained by differences in the behavior of females when they encountered different aphid species. Females of A. hordei rarely approach, sting, oviposit or host feed on aphids outside the genus Diuraphis, and they oviposit most frequently in D. noxia. From these results, we conclude that A. hordei is an excellent candidate for introduction into the USA to control D. noxia.

Aprostocetus fukutai is a specialist egg parasitoid of the citrus longhorned beetle Anoplophora chinensis, a high-risk invasive pest of hardwood trees. The parasitoid overwinters as diapausing mature larvae within the host egg and emerges in early summer in synchrony with the egg-laying peak of A. chinensis. This study investigated the parasitoid’s diapause survival in parasitized host eggs that either remained in potted trees under semi-natural conditions in southern France or were removed from the wood and held at four different humidities (44, 75, 85–93 and 100% RH) at 11 °C or four different temperature regimes (2, 5, 10 and 12.5 °C) at 100% RH in the laboratory. The temperature regimes reflect overwintering temperatures across the parasitoid’s geographical distribution in its native range. Results show that the parasitoid resumed its development to the adult stage at normal rearing conditions (22 °C, 100% RH, 14L:10D) after 6- or 7-months cold chilling at both the semi-natural and laboratory conditions. It had a low survival rate (36.7%) on potted plants due to desiccation or tree wound defense response. No parasitoids survived at 44% RH, but survival rate increased with humidity, reaching the highest (93.7%) at 100% RH. Survival rate also increased from 21.0% at 2 °C to 82.8% at 12.5 °C. Post-diapause developmental time decreased with increased humidity or temperature. There was no difference in the lifetime fecundity of emerged females from 2 and 12.5 °C. These results suggest that 100% RH and 12.5 °C are the most suitable diapause conditions for laboratory rearing of this parasitoid.