Nanoformulations with exopolysaccharides from cyanobacteria: enhancing the efficacy of bioactive molecules in the Mediterranean fruit fly control.

The increasing demand for food has required intensive use of pesticides which are hazardous to the ecosystem. A valid alternative is represented by biopesticides; however, these molecules are often insoluble in water, and poorly bioavailable. Nanopesticides can be engineered to reach a selected target with controlled release of the active principle. In this work, capsaicin, an irritant alkaloid from hot chili peppers, and hydroxytyrosol, a phenolic compound obtained from extra-virgin olive oil by-products, were loaded into innovative nanocarriers. These were designed ad hoc combining exopolysaccharides from the cyanobacteria Neocyanospira capsulata, and a lipid component, i.e., egg phosphatidylcholine. The polysaccharide was chosen for chemical affinity with the chitin of insect exoskeleton, while the lipids were introduced to modulate the carrier rigidity. The newly formed nanosystems were characterized by physico-chemical techniques and tested for their possible use in pest control programs. The Mediterranean Fruit Fly Ceratitis capitata Wiedemann, 1824 (Diptera, Tephriditae), a pest of the Mediterranean Region causing high economic losses, was used as a model insect. We found that the nanoformulations nanocarriers prepared in this work, were able to increase the ovicidal effect of hydroxytyrosol. Moreover, the formulation encapsulating either hydroxytyrosol or capsaicin were able to reduce the number of females landing on treated apricots.

Colour Preference of the Deer Ked Lipoptena fortisetosa (Diptera: Hippoboscidae).

Lipoptena fortisetosa, a deer ked native to Japan, has established itself in several European countries and was recently recorded in Italy. This hippoboscid ectoparasite can develop high density populations, causing annoyance to animals and concern regarding the potential risk of transmitting pathogens to humans. No monitoring or control methods for L. fortisetosa have been applied or tested up to now. This research evaluated the possible response of L. fortisetosa winged adults to different colours as the basis for a monitoring and control strategy. In the summer of 2020, a series of six differently coloured sticky panels were randomly set as traps in a wooded area used by deer for resting. The results indicated a clear preference of the deer ked for the blue panels that caught the highest number of flies during the experimental period. Lower numbers of flies were trapped on the red, green, black, and white panels, with the yellow panels recording the fewest captures. The response clearly demonstrates that this species displays a colour preference, and that coloured traps might be useful for monitoring and limiting this biting ectoparasite in natural areas harbouring wildlife and visited by people.

Emigration Effects Induced by Radio Frequency Treatment to Dates Infested by Carpophilus hemipterus.

The dried fruit beetle (Carpophilus hemipterus) is considered a key pest of dates, infesting fruits both in the field and during storage. Control measures against the species rely on the use of chemicals or heat treatments based on sunlight, hot air or radio frequency (RF) applications. Previous investigations that have aimed to define control procedures for a total disinfestation using RF treatments with different exposure durations have shown the typical behavior of adults in some trials, which, under the influence of temperature increases, started to escape from infested fruits. We focused on the application of different RF voltage-time combinations to induce the emigration of C. hemipterus adults from dates in order to produce a complete disinfestation. The results showed that the application of 2500 V RF for 8-10 min to infested dates resulted in nearly 100% of adults escaping from fruits, thereby cleaning the commodity with low or no mortality inside and outside the dates. These achievements provide a new strategy for controlling key insect pests of dates that could be applied at an industrial scale, allowing for the quick disinfestation of fruits without affecting the fruit with harmful substances, such as residues from chemical treatments, and without unwanted side effects on date quality.

The role of the antennae during courtship behaviour in the parasitic wasp Trichopria drosophilae.

We have studied the courtship behaviour of Trichopria drosophilae Perkins (Hymenoptera: Diapriidae), a pupal parasitoid of the common fruit fly Drosophila melanogaster Meigen (Diptera: Drosophilidae), to understand the role of the antennae. Virgin pairs of the parasitoid perform an intense and stereotyped antennal courtship, which leads to copulation. During antennation, the two male fourth antennomeres come into contact with the two apical female antennomeres, and thus the secretion produced by the sex pheromone gland is spread onto the female receptors. By preventing the transfer of the courtship pheromone from male to female antennae, mating was inhibited. Moreover, selective ablation of single antennae demonstrated that the courtship pheromone acts on contact. When antennae of both sexes were partially removed (ablation at the same side, i.e. right or left) courtship was successful and copulation occurred. In contrast, in the case of antennal ablation at opposite sides, courtship failed despite the short distance between secretion and receptors. These results confirm the hypothesis that T. drosophilae male antennal glands are the release site of a contact courtship pheromone, playing a key role in mating behaviour. The occurrence of male antennal glands in Hymenoptera and other insect orders is discussed.