Evaluation of Indigenous Entomopathogenic Nematodes as Potential Biocontrol Agents against Popillia japonica (Coleoptera: Scarabaeidae) in Northern Italy.

The natural presence of entomopathogenic nematodes (EPNs) has been investigated in the Piedmont region (Northern Italy) in areas infested by the Japanese beetle Popillia japonica. Thirty-nine out of 155 soil samples (25.2%) were positive for EPNs. Most of the samples contained only steinermatids (92.3%), 5.1% contained heterorhabditids, and one sample (2.6%) contained both genera. All the recovered isolates were identified at species level both morphologically and molecularly. Steinernema carpocapsae was the most abundant and it was mainly distributed in open habitats, such as perennial meadows, uncultivated soils, and cropland, characterized by sandy loam soil texture and acidic pH. Steinernema feltiae has been found associated mainly with closed habitats such as coniferous and deciduous woodland, characterized by sandy loam-texture and extremely acidic soil. The three isolates of Heterorhabditis bacteriophora were collected only in open habitats (perennial meadows and uncultivated fields) characterized by strongly acidic soils with sandy loam texture. The virulence of all EPN natural strains was evaluated by laboratory assays against P. japonica third-instar larvae collected during two different periods of the year (spring, autumn). The results showed that larval mortality was higher for pre-wintering larvae than post-wintering ones. The five more promising EPN isolates were tested in the semi-field assay in which H. bacteriophora natural strains have been shown to be more efficient in controlling P. japonica grubs. All of these results are finally discussed considering the use of these natural EPNs as biological control agents against P. japonica, within an eco-friendly perspective of management.

Scent of Jasmine Attracts Alien Invaders and Records on Citizen Science Platforms: Multiple Introductions of the Invasive Lacebug Corythauma ayyari (Drake, 1933) (Heteroptera: Tingidae) in Italy and the Mediterranean Basin.

The jasmine lacebug Corythauma ayyari is a pest of cultivated and ornamental plants mainly associated to Jasminum spp. This invasive insect is native to Asia, and it has been recently introduced in several countries, mainly within the Mediterranean basin. Here, we updated the known distribution of this species, including five new Italian regions (Liguria, Tuscany, Latium, Apulia, and Calabria); Salamis Island in Greece, and the Occitanie region in France. Citizen-science data have significantly contributed to the knowledge on species distribution, and the online platform for sharing biodiversity information can represent an effective tool for the early detection. Molecular analyses revealed that the specimens collected in Peninsular Italy and Sicily belong to a unique clade, suggesting the possibility of a single introduction, whereas those from Menton (France) and Calabria (Southern Italy) are separated from the others and probably originate from separated introductions.

Vitrification Assessment: Thermal Analysis of Cryoprotective Aqueous Solutions 1,2 Propanediol and Ethylene Glycol.

Cryopreservation of viable cells and cell materials is being developed for biological and biopharmaceutical applications. The inhibition of ice formation during the cooling and warming phase of vitrified living biological samples is important for their survival. The tendency to form glasses (glass transition temperature, Tg) upon cooling in the vitrification solution and the stability of the amorphous state upon warming to determine the critical cooling rate (Vccr) and critical warming rates (Vcwr) are evaluated. The study of thermal properties of ethylene glycol (EG) and 1,2-propanediol (PD) solutions were performed to improve vitrification through better understanding of their molecular mobility and viscosity. Two sets of aqueous solutions were tested. In group A, 35% EG (w/w) was added to different PD concentrations (5%, 10%, and 15%). In group B, 20% PD (w/w) was combined with varying concentrations of EG (20%, 24%, 27%, and 30%). Using the semiempirical model of Boutron, the values of Vccr and Vcwr for group A were 10, 8, <2.5°C/min, and 1.65 × 105, 678, 32°C/min, respectively. For group B, the values were 24, 10, <2.5, <2.5°C/min, and 9.5 × 103, 144, 48, 7°C/min, respectively. While the values of Vccr and Vcwr for 40% EG were 123 and 8.84 × 105°C/min, respectively. The methyl group in PD enhanced the vitreous state, lowering the melting point. Adding a small concentration of PD (3%) to VM3 vitrification solution improved and increased the Tg and enhanced their thermal stability. Analyzing the thermal properties of cryoprotectant is useful when designing the cryopreservation protocols.

Hexamermis popilliae n. sp. (Nematoda: Mermithidae) parasitizing the Japanese beetle Popillia japonica Newman (Coleoptera: Scarabaeidae) in Italy.

A new species of mermithid nematode, Hexamermis popilliae n. sp. (Nematoda: Mermithidae) is described from the Japanese beetle Popillia japonica Newman in Italy, an area of new introduction for this invasive pest. The combination of the following characters separates H. popilliae from other members of the genus Hexamermis Steiner, 1924: adult head obtuse; amphidial pouches slightly posterior to lateral head papillae in female but adjacent to lateral head papillae in males; amphidial openings large, well developed; amphidial pouches elliptical in females and oblong in males; cuticular vulvar cone well developed, vulvar lips greatly reduced or lacking, vagina curved at tip where meeting uteri, without reverse bend (not S-shaped), spicules slightly curved, with a slight bend in the basal portion, approximately equal to body width at cloaca. This is the first record of a species of Hexamermis parasitizing the Japanese beetle Popillia japonica. The only previous mention of mermithid nematodes from P. japonica was an undescribed species of Psammomermis in North America. Hexamermis popilliae will be evaluated as a potential biological control agent in an integrated control program of the Japanese beetle in Italy.

Characterization and comparison of Metarhizium strains isolated from Rhynchophorus ferrugineus.

Rhynchophorus ferrugineus is considered the worst pest of palm species, and few natural enemies are reported for this parasite in its area of origin. Here, we report the first recovery of the entomopathogenic fungus Metarhizium pingshaense associated with R. ferrugineus from Vietnam. The morphological, biochemical, and toxicological features of this strain were studied and compared with those of another Metarhizium strain associated with this weevil in Sicily (Italy), an area of recent introduction. The potential use of these fungi as biocontrol agents was tested against adult insects in laboratory trials and a similar mortality rate was found. Both strains were able to produce toxins and cuticle-degrading proteases, but they showed dissimilar enzymatic and toxicological profiles, suggesting a different virulence activity.