Over the past several decades, there has been a resurgence of interest in industrial hemp (Cannabis sativa L., Cannabaceae) cultivation. Besides fibre, seeds and oil, hemp contains high quantity of essential oil (EO). Hop (Humulus lupulus L., Cannabaceae) is a high-climbing, perennial vine, largely utilized in the brewing industry to add flavour and bitterness to beer. While it is known that hop also contains α- and ß-acids, and terpenes that have been found to be toxic, anti-feedant, and repellent for insects and mites, little is known about the bioactivity against problematic species of the hemp EO. In this study, the chemical composition of the EOs from C. sativa and H. lupulus was evaluated by GC-MS, and their acute toxicity was assessed against the Asian tiger mosquito Aedes albopictus (Skuse) (Diptera Culicidae) and, the freshwater bladder snail Physella acuta (Draparnaud) (Mollusca Physidae), two problematic invasive species. Furthermore, we evaluated the toxicity of both EOs against a non-target insect, the mayfly Cloeon dipterum L. (Ephemeroptera Baetidae). Both EOs were toxic against the three tested species. The most effective EO was the C. sativa, able to kill 100% of P. acuta snails starting from 100 μL L-1. C. sativa LC50 were 301.560, 282.174 and, 35.370 μL L-1, while H. lupulus LC50 were 330.855, 219.787 and, 118.653 μL L-1 against A. albopictus, C. dipterum and P. acuta, respectively. Relative median potency analysis showed that the C. sativa EO was more toxic than H. lupulus against A. albopictus and P. acuta, while H. lupulus was more toxic than C. sativa EO against C. dipterum. The most susceptible species to the two EOs was P. acuta, while A. albopictus resulted the least susceptible one
Spent hops is a waste produced in large amount by the brewing industry. Rhyzopertha dominica and Sitophilus granarius are insects that cause important economic losses of stored foods. In this study, for the first time, spent hops has been evaluated as source of essential oil (EO) and chemicals with repellent activity against R. dominica and S. granarius. Spent hops EO yield was 0.11%. The terpenes myrcene, α-humulene, and β-caryophyllene were its main components (47%). Spent hops EO RD50 values were 0.01 and 0.19 μL cm -2 for R. dominica and S. granarius, respectively. Among the chemicals, myrcene was able to exert the highest repellency against R. dominica (RD50 = 0.27 µM cm -2 ) while limonene was the most effective compound against S. granarius (RD50 = 0.89 µM cm -2 ). These results indicate spent hops as an excellent source of EO and chemicals to be utilized as low-cost eco-friendly insect pests repellents in the protection of stored food. Keywords: Spent hops . Essential oil . Terpenes . Rhyzopertha dominica . Sitophilus granarius . Repellence Key Message• No information is available about the bioactivity of extracts from hop or spent hops against stored food insect pests.• Spent hops EO resulted rich in bio-active substances (myrcene, 24.2%)• Spent hops EO was strongly repellent activity against R. dominica and S. granarius (RD50 = 0.008 and 0.191 µL cm -2 , respectively).
BackgroundSynanthropic flies play a considerable role in the transmission of pathogenic and non-pathogenic microorganisms. In this work, the essential oil (EO) of two aromatic plants, Artemisia annua and Artemisia dracunculus, were evaluated for their abilities to control the blowfly Calliphora vomitoria. Artemisia annua and A. dracunculus EOs were extracted, analysed and tested in laboratory bioassays. Besides, the physiology of EOs toxicity and the EOs antibacterial and antifungal properties were evaluated.ResultsBoth Artemisia EOs deterred C. vomitoria oviposition on fresh beef meat. At 0.05 μl cm-2 A. dracunculus EO completely inhibited C. vomitoria oviposition. Toxicity tests, by contact, showed LD50 of 0.49 and 0.79 μl EO per fly for A. dracunculus and A. annua, respectively. By fumigation, LC50 values were 49.55 and 88.09 μl l-1 air for A. dracunculus and A. annua, respectively. EOs AChE inhibition in C. vomitoria (IC50 = 202.6 and 472.4 mg l-1, respectively, for A. dracunculus and A. annua) indicated that insect neural sites are targeted by the EOs toxicity. Finally, the antibacterial and antifungal activities of the two Artemisia EOs may assist in the reduction of transmission of microbial infections/contaminations.ConclusionsResults suggest that Artemisia EOs could be of use in the control of C. vomitoria, a common vector of pathogenic microorganisms and agent of human and animal cutaneous myiasis. The prevention of pathogenic and parasitic infections is a priority for human and animal health. The Artemisia EOs could represent an eco-friendly, low-cost alternative to synthetic repellents and insecticides to fight synanthropic disease-carrying blowflies.
The growing interest in the development of green pest management strategies is leading to the exploitation of essential oils (EOs) as promising botanical pesticides. In this respect, nanotechnology could efficiently support the use of EOs through their encapsulation into stable nanoformulations, such as nanoemulsions (NEs), to improve their stability and efficacy. This technology assures the improvement of the chemical stability, hydrophilicity, and environmental persistence of EOs, giving an added value for the fabrication of natural insecticides effective against a wide spectrum of insect vectors and pests of public and agronomical importance. Carlina acaulis (Asteraceae) root EO has been recently proposed as a promising ingredient of a new generation of botanical insecticides. In the present study, a highly stable C. acaulis-based NE was developed. Interestingly, such a nanosystem was able to encapsulate 6% (w/w) of C. acaulis EO, showing a mean diameter of around 140 nm and a SOR (surfactant-to-oil ratio) of 0.6. Its stability was evaluated in a storage period of six months and corroborated by an accelerated stability study. Therefore, the C. acaulis EO and C. acaulis-based NE were evaluated for their toxicity against 1st instar larvae of the European grapevine moth (EGVM), Lobesia botrana (Denis & Schiffermüller, 1775) (Lepidoptera: Tortricidae), a major vineyard pest. The chemical composition of C. acaulis EO was investigated by gas chromatography–mass spectrometry (GC–MS) revealing carlina oxide, a polyacetylene, as the main constituent. In toxicity assays, both the C. acaulis EO and the C. acaulis-based NE were highly toxic to L. botrana larvae, with LC50 values of 7.299 and 9.044 µL/mL for C. acaulis EO and NE, respectively. The C. acaulis-based NE represents a promising option to develop highly stable botanical insecticides for pest management. To date, this study represents the first evidence about the insecticidal toxicity of EOs and EO-based NEs against this major grapevine pest.
and are microsporidia which play an important role in the epidemiology of honeybee microsporidiosis worldwide. Nosemiasis reduces honeybee population size and causes significant losses in honey production. To the best of our knowledge, limited information is available about the prevalence of nosemiasis in Italy. In this research, we determined the occurrence of infection in Central Italy. Thirty-eight seemingly healthy apiaries (2 to 4 hives each) were randomly selected and screened from April to September 2014 ( = 11) or from May to September 2015 ( = 27). The apiaries were located in six areas of Central Italy, including Lucca ( = 11), Massa Carrara ( = 9), Pisa ( = 9), Leghorn ( = 7), Florence ( = 1), and Prato ( = 1) provinces. Light microscopy was carried out according to current OIE recommendations to screen the presence of microsporidiosis in adult worker honeybees. Since the morphological characteristics of and spores are similar and can hardly be distinguished by optical microscopy, all samples were also screened by multiplex polymerase chain reaction (M-PCR) assay based on 16S rRNAgenetargeted species-specific primers to differentiate from Furthermore, PCR-positive samples were also sequenced to confirm the species of amplified DNA. Notably, spores were detected in samples from 24 out of 38 (63.2%, 95% CI: 47.8-78.5%) apiaries. Positivity rates in single provinces were 10/11, 8/9, 3/9, 1/7, or 1/1 ( = 2). A full agreement (Cohen's Kappa = 1) was assessed between microscopy and M-PCR. Based on M-PCR and DNA sequencing results, only was found. Overall, our results highlighted that infection occurs frequently in the cohort of honeybee populations that was examined despite the lack of clinical signs. These findings suggest that colony disease outbreaks might result from environmental factors that lead to higher susceptibility of honeybees to this microsporidian.
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