China
Africa
Explore chapters and articles related to this topic
The Ecology of Parasitism
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Other examples of medication are provided by insects. Consumption of ethanol-containing food by larvae of Drosophila melanogaster resulted in a two-fold decrease in infection intensity and a 24-fold increase in survival to adulthood following exposure to the ethanol-sensitive parasitoid Leptopilina heterotoma (see also Chapter 4, p. 146). Honey bees accumulate stores of propolis (Figure 6.29), a mixture of beeswax and plant resins in their hives. The resins are known to contain compounds that can provide prophylactic or therapeutic protection from bee ectoparasites like Varroa destructor mites (Figure 6.29B and Box 1.2, Figure 1).
Biological Activities of Syzygium cumini and Allied Species
Published in K. N. Nair, The Genus Syzygium, 2017
Varughese George, Palpu Pushpangadan
Mite lethality was estimated using a complete exposure method test with the S. aromaticum (clove) oil at different concentrations, and a systemic administration method of oil at different concentrations diluted in syrup was placed in feeders for bees. The LC50 for the complete exposure method at 24 h was 0.59 μl/dish. The inferior and superior limits obtained were 0.47 × 10−6 and 1.22 μl/dish, respectively. The LC50 estimated at 48 h showed a slight decrease compared with that recorded at 24 h. Ratio selection (LC50 of Apis mellifera/LC50 of Varroa destructor) for the complete exposure method was 26.46 and 13.35 for 24 and 48 h, respectively. Regarding the systemic administration method, the mite LC50 at 24 h was 12,300 ppm. The inferior and superior limits calculated were 9,214 and 15,178 ppm, respectively. The LC50 estimated at 48 h showed a slight decrease compared with that recorded at 24 h. Ratio selection for the systemic administration method was 3.05 and 2.22 for 24 and 48 h, respectively. S. aromaticum oil was found to be an attractant for V. destructor at 4.8% (w/w) concentration. The results showed that oil toxicity against V. destructor differed depending on its administration (Maggi et al. 2010).
Use of Essential Oils in Agriculture
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Catherine Regnault-Roger, Susanne Hemetsberger, Gerhard Buchbauer
EOs are natural products, which are excellent alternatives to synthetic products because they reduce negative impacts on human health and the environment (Koul et al., 2008). Even though there are a lot of botanical insecticides available, from 1980 to 2000, only one single product was registered in the United States and Europe, which is called Neem (now considered an endocrine disruptor). It is obtained by the seeds of the Indian tree Azadirachta indica, Meliaceae. In the last few years, EOs also obtained influence as botanical insecticides in the United States. But, due to the relatively slow action, variable efficacy, lack of persistence and inconsistent availability of natural products, they still cannot compete against synthetic pesticides. On the other hand, it is not necessary to kill harmful insects since botanical insecticides, like EOs, can also be used as repellents against animals. Moreover, those natural pesticides can also be mixed with synthetic products which could lessen the needed quantities of pesticides and improve the environmental problems which were caused by excessive use of synthetic pesticides. Especially, developing countries could benefit from the increased use of botanical pesticides, such as EOs, since farmers are more familiar with plant extracts and EOs they can do by themselves. They often use pesticides and do not know about the dangers because many of them do not receive any information and they are often unable to read the official languages in which the instructions are written (Isman, 2008). In static water, eugenol appears to be 1500 times less toxic than pyrethrum, which is also a botanical insecticide, and not more than 15,000 times less toxic than the organophosphate insecticide azinphosmethyl. Moreover, eugenol is volatile, which means that its half-life is extremely short. After about two days, there will be no eugenol left, which also avoids rare side effects of EOs (Isman, 2000). Also, the tobacco cutworm, which is a severe problem to vegetable and tobacco crops in Asia, can be killed by compounds of EOs, namely thymol, carvacrol, pulegone, eugenol, and trans-anethole, even though it is quite resistant (Hummelbrunner et al., 2001). Many monoterpenes like (+)-limonene, pinene, and Δ3-carene show acaricidal activity. Carvomenthenol and terpinen-4-ol proved to cause highest toxicity against mites (Ibrahim et al., 2008). Eucalyptus EO was tested on several parasites, such as Varroa destructor (Varroa mite), Tetranychus urticae, Phytoseiulus perisimilis, and Boophilus microplus. The studies concluded that several Eucalyptus sp. (Myrtaceae) EOs can be used as acaricides (Batish et al., 2008). T. urticae can be killed by EOs obtained from Satureja hortensis L. (Lamiaceae), Ocimum basilicum L. (Lamiacae), and Thymus vulgaris L. (Lamiaceae) (Aslan et al., 2004). EOs do not only act as deterrents but also as attractants toward insects. Ethanolic extracts of Rosmarinus officinalis L. (Lamiaceae) EO attracted the moth Loberia botrana, a pest of grape berries (Katerinopoulos et al., 2005).
Wolbachia-Virus interactions and arbovirus control through population replacement in mosquitoes
Published in Pathogens and Global Health, 2023
Thomas H Ant, Maria Vittoria Mancini, Cameron J McNamara, Stephanie M Rainey, Steven P Sinkins
Grau et al. [106] investigated a potential correlation between the presence of a native Wolbachia infection and the frequency of deformed wing virus (DWV) in the parasitic honeybee mite Varroa destructor, with specimens collected from several different apiaries. Two sets of primers were used for Wolbachia detection in these samples, with the authors reporting a significant positive correlation between infection frequency with Wolbachia and DWV with one primer set but not with the other. As there was little agreement in infection frequency between the two primer sets (in one of the hives the different PCR assays produced a disparity in Wolbachia infection frequency in mites that ranged from 0% to 100%), there are concerns over the sensitivity and/or specificity of the PCR assays used in the detection of Wolbachia. It is possible that multiple strains of Wolbachia naturally infect V. destructor, which could explain the inconsistency between primers sets; however, it is difficult to draw definitive conclusions about potential correlations with DWV without more robust characterization of the Wolbachia present.