Alkane-priming of Beauveria bassiana strains to improve biocontrol of the redbanded stink bug Piezodorus guildinii and the bronze bug Thaumastocoris peregrinus

Insect Epicuticle hydrocarbons (CHC) are known to be important determinants in the susceptibility degree of insects to fungal entomopathogens. Five Beauveria bassiana isolates were phenotypically analyzed regarding their response to CHC nutrition and their pathogenicity and virulence towards high fungal-susceptible Thaumastocoris peregrinus and low fungal-susceptible Piezodorus guildinii, which are important hemipteran pests in eucalyptus and soybean plantations, respectively. Two of these isolates, resulting the most (ILBB308) and the least (ILBB299) virulent to P. guildinii, were also evaluated at gene expression level after growth on n-pentadecane. B. bassiana most virulent isolate ILBB308 showed the lowest growth on most evaluated CHC media. However, this isolate distinctively induced most of the analyzed genes involved in CHC assimilation, cuticle degradation and stress tolerance. Virulence towards low susceptibility P. guildinii was enhanced in both hypervirulent ILB308 and hypovirulent ILBB299 isolates after growth on n-pentadecane as the sole carbon source, whereas virulence enhancement towards high susceptibility T. peregrinus was not observed in alkane-grown fungi. Virulence enhancement towards P. guildinii could be mostly explained by a priming effect produced by CHC on the induction of some genes related to hydrocarbon assimilation in ILB 205 and ILB 308, such as hydrophobin (Bbhyd2) and cytochrome P450 genes (BbCyp52g11 and BbCyp52x1), and partially by the induction of genes related to cuticle degradation (Bbchit and Bbcdep1) and stress tolerance (Bbsod1) observed only in ILB308.

First record from Calabria (southern Italy) of the “bronze bug” Thaumastocoris peregrinus Carpintero & Dellapé, 2006, alien Eucalyptus pest native to Australia (Hemiptera: Heteroptera: Thaumastocoridae)

The occurrence in Calabria (southern Italy) of Thaumastocoris peregrinus Carpintero & Dellapé, 2006, alien pest on various species of Eucalyptus, native to Australia, is reported for the first time. The first specimens were collected in September 2019; later the authors found feeding damage on the leaves, eggs batches and the various stages of the insect in various localities in Reggio Calabria (Italy). Notes on its distribution and biology are reported.

Insect pest species of Eucalyptus in Gibraltar

Four invasive eucalypt-feeding insects, native to Australia, are recorded from Gibraltar for the first time: the gall-forming wasps Ophelimus maskelli (Ashmead) and Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae), the lerp-forming psyllid Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae), and the bronze bug Thaumastocoris peregrinus Carpintero & Dellapé (Hemiptera: Thaumastocoridae), whilst the status of two Eucalyptus longhorned borers, Phoracantha recurva Newman and P. semipunctata (Fabricius) (Coleoptera: Cerambycidae), is summarised. The former five species have been found on the red-gum tree Eucalyptus camaldulensis Dehnh., growing in the urban environment in Gibraltar. The potential impact of these invasive species is discussed.

The ongoing dispersion of the Eucalyptus bronze bug (Thaumastocoris peregrinus) in Spain

Aim of stydy: Thaumastocoris peregrinus (Carpinteiro & Dellapé, 2006) is notable for its dispersion potential, and for its damage to a wide range of hosts of the genus Eucalyptus. The intense movement of people and cargo between continents contributes to the success of its geographical distribution on the globe and hinders the adoption of preventive measures. The celerity and precision in the identification of T. peregrinus, as well as its invasion and dispersion routes are fundamental for the implementation of measures to prevent new invasions.Area of Study: Park of Retiro in the community of Madrid, Spain, where T. peregrinus is present.Material and methods: In this paper we analysed this COI mtDNA gene in T. peregrinus, using samples collected in a park in Madrid urban area, to study the possible ways of introduction of this insect in Spain. This goal can be achieved using molecular methods to amplify and sequence the COI mtDNA gene, which is used as a barcode gene.Results: The results confirm that the population found in Madrid belong to T. peregrinus species and that all the specimens are from the same maternal lineage.Research highlights: We present the first molecular information of the population of T. peregrinus present in the country, and suggest and discuss possible routes of introduction of the species in Spain.

ECOPHYSIOLOGICAL ANALYSIS OF Eucalyptus camaldulensis (DEHNH) SUBMITTED TO ATTACK FROM Thaumastocoris peregrinus (CARPINTERO & DELLAPE)

ABSTRACT Works correlating the effect of a bronze bug attack on ecophysiological aspects of eucalyptus can be used in selection programs for resistant genetic materials. The objective of this study was to evaluate the injuries caused by Thaumastocoris peregrinus (Carpintero & Dellape) through the ecophysiological analysis of Eucalyptus camaldulensis (Dehnh). The experiment was conducted in a completely randomized design, with two groups of plants, infested and non-infested, kept in a room at 25 ± 2 °C, relative humidity 60 ± 2% and a photoperiod of 12 hours. For 26 days, every 48 hours, the chlorophyll a fluorescence, using the electron transport rate (ETR) and the potential quantum efficiency (Fv/Fm), was measured, in addition to the leaf chlorophyll content of the plants. The variables observed were analyzed in relation to treatments and times using a mixed linear model, with plants and leaves being random effects. Plants protected from insect attack showed better results over the experimental period. However, the attack from the bronze bug negatively affected all the ecophysiological variables evaluated in E. camaldulensis, indicating a possible compromise of the photosynthetic apparatus of the plants.