Francesca Laudani

Larvicidal Effects of Four Citrus Peel Essential Oils Against the Arbovirus Vector Aedes albopictus (Diptera: Culicidae).

Abstract In this study, we evaluated the larvicidal activity of four citrus essential oils (EOs; sweet orange, mandarin, bergamot, and lemon) against the arbovirus vector Aedes albopictus (Skuse) (Diptera: Culicidae) under laboratory conditions. Through gas chromatography–mass spectrometry (GC–MS) analyses, we found that in sweet orange, mandarin, and lemon EOs, limonene was the most abundant compound, whereas linalyl acetate was the most abundant in the bergamot EO. All tested EOs showed a marked larvicidal activity, in particular sweet orange, lemon, and bergamot that killed all treated larvae. After 24 h of exposure, the LC50 values of the tested citrus EOs ranged from 145.27 (lemon EO) to 318.07 mg liter–1 (mandarin EO), while LC95 ranged from 295.13 to 832.44 mg liter–1. After 48 h of exposure, the estimated LC50 values decreased to values ranging from 117.29 to 209.38 mg liter–1, while LC95 ranged from 231.85 to 537.36 mg liter–1. The results obtained from these evaluations, together with the large availability at reasonable costs of citrus EOs, are promising for the potential development of a new botanical mosquitocide.

A scientific note on a new pest for European honeybees: first report of small hive beetle Aethina tumida ,( Coleoptera: Nitidulidae) in Italy

The small hive beetle (SHB), Aethina tumida Murray (Coleoptera Nitidulidae), is an important pest of honeybees in many parts of the world. The beetle is native to sub-Saharan Africa and was unintentionally introduced into USA (1996), Australia (2001) and in Canada (2002) (Ellis and Munn, 2005; Neumann and Ellis 2008). In Europe the SHB was discovered in 2005 in a consignment of queens imported from Texas (USA) into Portugal and destroyed by the Portuguese National Veterinarian Services (Murilhas, 2005). Since then, Europe remained free from this pest.

Fumigant bioactivity of five Citrus essential oils against Tribolium confusum

During the past decades, the huge use of pesticides caused several environmental problems, so research investigations moved to find a series of compounds with selective toxicity, of a biodegradable and environment-friendly nature, maintaining a positive action in crop and stored products protection. In this perspective, interesting results in the control of pests and fungal pathogens were obtained using essential oils, which are compounds produced by many species of plants as secondary metabolites. The purpose of this research was to evaluate the fumigant activity of five Citrus essential oils against the confused flour beetle Tribolium confusum Du Val, planning a possible employment in the mill industry. The fumigant effectiveness was evaluated 24, 48, 72 hours and 7 days after the start of exposure and each essential oil was analyzed by means of GC and GC/MS. Further evaluations about the toxicity of these compounds were made by partially filling the glass vials with food matrix, in order to assess the possible interference of this matter on the active compounds. The data obtained indicated that, at a low level of fumigant concentration, essential oils can effectively control stored product pests; in the presence of debris, like flour, the efficacy decreased. Plant extracts caused also increased mortality levels after the end of fumigation. The results obtained from this experimentation confirm the efficacy of essential oils in pest control and, in particular, against stored product pests.

Hymenoptera wasps associated with the Asian gall wasp of chestnut (Dryocosmus kuriphilus) in Calabria, Italy.

The parasitoid complex of the Asian chestnut gall wasp Drycosmus kuriphilus Yasumatsu was studied in Calabria (Italy). A total of 14 different species of parasitoids were collected, of which three are recorded on the Asian gall wasp for the first time. The composition of the parasitoid complex collected in Calabria was compared with that reported from Italy and from Europe. The altitude of the sites of collection seemed to have an effect on the distribution and abundance of the single species of parasitoids.

Population dynamics and spread of Unaspis yanonensis in Calabria, Italy

The occurrence of Unaspis yanonensis (Kuwana) (Hemiptera: Diaspididae) in Calabria (southern Italy) poses a serious threat to citrus cultivation. A regional survey was performed to record information about its distribution in local citrus orchards. Field population dynamics were also studied. The arrowhead scale, U. yanonensis, was recorded in the two main citrus cultivation areas of Calabria. In the investigated environments U. yanonensis completed two generations per year; a typical bi-modal oviposition was recorded. The arrowhead scale overwintered as second-instar males and pre-ovipositing females.

A novel GIS-based approach to assess beekeeping suitability of Mediterranean lands

Honeybees are critically important for the environment and to the economy. However, there are in substantial decline worldwide, leading to serious threat to the stability and yield of food crops. Beekeeping is of pivotal importance, combining the wide economical aspect of honey production and the important ecological services provided by honeybees. In this scenario, the prompt identification of beekeeping areas is strategic, since it maximised productivity and lowered the risks of colony losses. Fuzzy logic is an ideal approach for problem-solving tasks, as it is specifically designed to manage problems with a high degree of uncertainty. This research tested a novel GIS-based approach to assess beekeeping suitability of lands located in Calabria (Southern Italy), without relying to Analytic Hierarchy Process – Multiple Criteria Decision Making (AHP-MCDM), thus avoiding the constraints due to the technique and decision makers’ influences. Furthermore, the data used here were completely retrieved from open access sources, highlighting that our approach is characterized by low costs and can be easily reproduced for a wide arrays of geographical contexts. Notably, the results obtained by our experiments were validated by the actual beekeeping reality. Besides beekeeping, the use of this system could not only be applied in beekeeping land suitability evaluations, but may be successfully extended to other types of land suitability evaluations.

Bees visiting flowers of Thymus longicaulis (Lamiaceae)

The aim of this study was to investigate the bee fauna foraging on Thymus longicaulis flowers. Samplings were conducted walking along a transect during the T. longicaulis blooming period (April–June). A total of 547 bee specimens, belonging to 40 different species, were recorded during the survey. Apis mellifera and Bombus terrestris were the most abundant visitors that foraged on thyme. Pollen grains collected on the bodies of the bees suggest that these pollinators may play an important role in the pollination of this plant.

RNAi-mediated gene silencing in Rhynchophorus ferrugineus (Oliver) (Coleoptera: Curculionidae)

Abstract RNA interference (RNAi) is a powerful strategy for gene function analysis, and it is also widely studied in view of a promising use in pest control. The red palm weevil, Rhynchophorus ferrugineus (Oliver) (Coleoptera: Curculionidae), is one of the most devastating pests of palm in the world. Conventional pest management practices are not adequate to control this insect, thus the development of efficient approaches with minimal environmental impact are needed. In this work, the potential of RNAi in R. ferrugineus has been investigated through the silencing of three different genes (α-amylase, V-ATPase, Ecdysone receptor). For each gene we tested two different doses (1,500 and 5,500 ng) and two delivery techniques (injection and ingestion), evaluating both gene knockdown and mortality on insects. Results show that RNAi mediated gene silencing in R. ferrugineus varies from gene to gene, and that the response is dose-dependent, with stronger effects when dsRNA was administered by injection. In parallel, the same study was carried out with the model organism Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), with results showing a different pattern of response, although the two insects belong to the same order.