Roberto Rizzo

In the framework of integrated pest management, plant-based insecticides represent a promising tool for the control of insect pests. Indeed, N-alkylamides extracted from Acmella oleracea (L.) RK Jansen (Asteraceae) have been recently studied for their insecticidal properties. The encapsulation of these substances into stable formulations, like nanoemulsions (NEs), could boost their efficacy and stability. Herein, a N-alkylamide-enriched fraction (AEF) encapsulated into a stable NE was tested against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), a key tomato pest, able to develop resistance towards chemical insecticides. Acmella oleracea was reported to be effective against many target species, but this is the first time that this extract was tested against T. absoluta in terms of toxicity against eggs, ingestion toxicity on larvae and repellence on adults. The AEF, containing 42.8% of spilanthol, was prepared by combining two eco-friendly techniques, namely supercritical CO₂ extraction and wiped-film short path molecular distillation, and then encapsulated into a stable NE. Preliminary tests on the phytotoxicity of the AEF-NEs at 0.25 and 0.5% (w/w) a.i., compared with a control NE solution (i.e., the AEF-free NE) and a negative control (distilled water), showed a negative effect on tomato plants at the highest concentration. On this basis, three concentrations (0.06, 0.125, and 0.25% a.i.) were evaluated against eggs (topical toxicity), larvae of 2nd instar (ingestion and topical toxicity), and adults (ovideterrence) of T. absoluta. The results showed that all adopted AEF-NE concentrations caused a significant inhibition in egg hatching (>20%). The larval survival, at the end of the evaluation (72 h), in ingestion toxicity tests were significantly different in the AEF-NEs at 0.06, 0.12, and 0.25% (56.7, 33.3 and 26.7%, respectively) compared with control NE and distilled water (100% both). Similar results were obtained in the adult emergence in ingestion toxicity comparing AEF-NEs at 0.06, 0.12, and 0.25% (64.7, 50.0 and 75.0%, respectively) with control NE and distilled water (100% both). Finally, a significant ovideterrent effect was shown by the concentrations 0.125 and 0.25% of the AEF-NEs (% of egg laid: 7.5 and 27.4% respectively), compared with distilled water. Overall, the AEF-NE tested showed promising and encouraging effectiveness as ovicidal and larvicidal against T. absoluta. This supports its potential use as an effective alternative to synthetic products for the control of this important pest.

Among hazelnut phytophagous insects, the box bug Gonocerus acuteangulatus is a key pest in Southern Italy that severely compromise the production of healthy hazelnut fruits with severe economic losses. Currently, the box bug is controlled by many chemical control methods, but biological control could represent a promising tool. An intensive monitoring program of G. acuteangulatus egg parasitoids in five Sicilian organic hazelnut orchards was carried out. Adults, nymphs, and eggs (parasitized and non-parasitized) of G. acuteangulatus were collected. Moreover, hazelnut fruit samples were observed to assess fruit damage. Five parasitoid species emerged from G. acuteangulatus eggs: Anastatus bifasciatus, Hadronotus bosellii, H. muscaeformis, Trissolcus belenus, and Ooencyrtus sp. Anastatus bifasciatus was the most widespread species, followed by H. bosellii. The highest parasitoid diversity occurred at mid-elevation sites. Fruit damage remained substantial, indicating that natural parasitism may not provide satisfactory pest control. Here, field emergence of T. belenus from G. acuteangulatus eggs demonstrates a host association historically reported as T. grandis. Therefore, this study updates and expands the parasitoid assemblage associated with G. acuteangulatus by revisiting historical records with contemporary field evidence for future augmentative or conservation biocontrol program against the box bug.

Over the last two decades, mango cultivation in Sicily showed a steady increase of cultivated areas. This expansion has also facilitated the introduction of potentially harmful alien species. This paper reports the presence of the eriophyid mite Cisaberoptus kenyae Keifer (Acari: Eriophyidae) for the first time in Sicily and, therefore in Europe. In the perspective of a potential further expansion of mango also in other European areas as a consequence of the climatic changes, a brief overview of current knowledge on this species is also provided.

The tomato russet mite, Aculops lycopersici, is considered one of the most important crop pests globally. The main control strategy is based on synthetic acaricides; however, they create resistant strains and ecological risks. In this context, biopesticides could be a viable and sustainable alternative for eriophyid control. In the present study, the toxic effects of a N-alkylamides-enriched extract obtained from Acmella oleracea and of carlina oxide, the main bioactive component of Carlina acaulis, on A. lycopersici were evaluated, as well as their side effects on the phytoseiid Typhlodromus exhilaratus under laboratory conditions. Six concentrations were tested for each product against A. lycopersici adults (0, 320, 640, 1280, 2500, and 5000 μL L⁻¹), and the median concentration (1280 μL L⁻¹) was evaluated against eggs and females of the phytoseiid T. exhilaratus. Both the N-alkylamides-enriched extract and carlina oxide showed total lethal effects (100% of mortality) towards A. lycopersici at the two highest concentrations. Moderate-to-high mortality was also recorded with the lower concentrations: from 42.22 to 97.78%. Probit analysis identified LC₅₀ values of 205.32 μL L⁻¹ for carlina oxide and 253.79 μL L⁻¹ for the N-alkylamides-enriched extract, respectively. Carlina oxide showed a moderate ovicidal effect on T. exhilaratus eggs (50.00% hatching rate) on T. exhilaratus, and caused 39.13% mortality on females, whereas the N-alkylamides-enriched extract was less toxic, with a hatching rate of 88.00% and a mortality rate of 18.75% on females. In conclusion, carlina oxide and the N-alkylamides-enriched extract showed high toxicity on A. lycopersici, with a reduced effect on phytoseiid. These results highlight the potential of these products as sustainable means for the management of tomato russet mite.

Tomato russet mite, Aculops lycopersici is considered one of the most important crop pests globally. The main control strategy is based on synthetic acaricides which, however, create resistant strains and ecological risks. In this context, biopesticides could be a viable and sustainable alternative for the eriophyid control. In the present study, the toxic effects of a N-alkylamides-enriched extract obtained from Acmella oleracea and of carlina oxide, the main bioactive component of Carlina acaulis, on A. lycopersici were evaluated, as well as their side effects on the phytoseiid Typhlodromus exhilaratus Ragusa under laboratory conditions. Six concentrations were tested for each product against A. lycopersici adults (0, 320, 640, 1280, 2500 and 5000 μL L^-1), and the median concentration (1280 μL L^-1) was evaluated against eggs and females of the phytoseiid T. exhilaratus. Both the N-alkylamides-enriched extract and carlina oxide showed total lethal effects (100% of mortality) towards A. lycopersici at the two highest concentrations. Moderate to high mortality was also recorded with the lower concentrations: from 42.22 to 97.78%. Probit analysis identified LC₅₀ values of 205.32 μL L^-1for carlina oxide and 253.79 μL L^-1 for the N-alkylamides-enriched extract, respectively. Carlina oxide showed a moderate ovicidal effect on T. exhilaratus eggs (50.00% hatching rate) on T. exhilaratus, and caused 39.13% mortality on females, whereas the N-alkylamides-enriched extract was less toxic, with a hatching rate of 88.00% and a mortality rate of 18.75% on females. In conclusion, carlina oxide and the N-alkylamides-enriched extract showed high toxicity on A. lycopersici, with a reduced effect on phytoseiid. These results highlight the potential of these products as sustainable means for the management of tomato russet mite.

Encarsia protransvena (Hymenoptera: Aphelinidae) is recorded here for the first time in Italy as a parasitoid of the whitefly Singhiella simplex (Hemiptera: Aleyrodidae), one of the most invasive alien pests of exotic Ficus species. Singhiella simplex, originating from the Oriental region, has established a global presence. Monitoring of the whitefly and its parasitoids was conducted in the southern areas of Italy, providing crucial insights into their distribution and interactions. The taxonomic identity of E. protransvena, was confirmed by scrutiny of morphological and molecular taxonomic characters. At the time of writing, we also obtained some specimens of Encarsia hispida from the host collected in Campania. We reserve the right to provide bio-ethological information on the species in the future. Comprehensive illustrations and diagnostic features are provided for the host and the parasitoids. An identification key is included for all Encarsia species associated with S. simplex, which provides a valuable tool to distinguish these aphelinid wasps for future research and applications in biological control programs.

Plant essential oil (EO)-based insecticides represent a promising tool for IPM, though their formulation is limited by poor physio-chemical properties. EO encapsulation into stable formulations, like nano emulsions (NEs), could boost EO efficacy and stability. Carlina acaulis roots contain an EO recently studied for its excellent insecticidal activities, and chiefly composed by carlina oxide (>97%). Herein, we developed two carlina oxide NEs (0.25% and 0.5% w/w) through ultrasounds exposure and characterized them by dynamic light scattering. The NE insecticidal and repellent activities were investigated against T. absoluta eggs and larvae, and adults, respectively. 0.25% and 0.5% NEs showed a monomodal size distribution with a Z-average size of 113.87±1.32 nm and 127.27±0.47 nm, respectively. The polydispersity indexes measured at 0.15±0.01 and 0.16±0.01 indicate a low grade of polydispersity. The 0.25% NE showed significant contact toxicity on T. absoluta eggs, with a maximum egg hatching inhibition of 85.7% 11 days post-treatment. The highest larvicidal effect was observed in translaminar toxicity tests, with complete mortality after 24 h. The NE did not achieve significant oviposition deterrence. Overall, the tested NE showed promising effectiveness as ovicide and larvicide on T. absoluta, highlighting the need of further research shedding light on its modes of action, as well as to evaluate lethal and sublethal effects on tomato biological control agents and pollinators.

BACKGROUND: Tetranychus urticae Koch, is a polyphagous and damaging pest, presenting several resistant populations worldwide. Among new and more environmentally friendly control tools, botanical pesticides represent a valuable alternative to synthetic ones within integrated pest management strategies. Accordingly, we investigated the lethal and sublethal effects of carlina oxide isolated from Carlina acaulis (Asteraceae) roots on T. urticae and its natural enemy, the predatory mite, Neoseiulus californicus (McGregor).RESULTS: Carlina oxide (98.7% pure compound) was used for acaricidal tests on eggs, nymphs, and adult females of T. urticae (concentrations of 312.5, 625, 1250, 2500 and 5000 μL L⁻¹), and eggs and females of N. californicus (1250 and 5000 μL L⁻¹ on eggs and females, respectively). Behavioral two‐choice tests were also conducted on phytoseiid females. Carlina oxide toxicity was higher on T. urticae females than nymphs (median lethal dose 1145 and 1825 μL L⁻¹, respectively), whereas egg mortality and mean hatching time were significantly affected by all tested concentrations. A decreasing daily oviposition rate for T. urticae was recorded with concentrations ranging from 625 to 5000 μL L⁻¹, whereas negative effects on the population growth rate were recorded only with the three higher concentrations (1250, 2500 and 5000 μL L⁻¹). No toxic effect on N. californicus females was found, but a strong repellent activity lasting for 48 h from application was recorded.CONCLUSION: Carlina oxide reduced longevity and fecundity of T. urticae adults, but not of N. californicus. This selective property allows us to propose it as a novel active ingredient of ecofriendly acaricides for T. urticae management. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.