The common grape vine, Vitis vinifera, is a widely known plant with commercial and pharmacological value. The plant hosts a variety of microorganisms known as endophytes that can live within the tissues of the plant for a considerable time period, or even their whole life cycle. The fungus Beauveria bassiana is a well-studied endophyte which can colonize a variety of plants in many ways and in different parts of the plant. In this study, we examined the effect of the endophytic fungus B. bassiana on the growth of V. vinifera. The results demonstrated not only a successful colonization of the endophyte, but also a noteworthy impact on the growth of the V. vinifera root without harming the plant in any way. The fungus was also re-isolated from the parts of the plant using inst bait method. Overall, the study demonstrates the capability of B. bassiana to colonize V. vinifera plants, adding to the already existing knowledge of its endophytic activity, and highlighting its beneficial impact on the root growth.
Trichoderma fungi are promising candidates for biocontrol agents and plant growth promoters. Trichoderma atrobrunneum and T. simmonsii were evaluated for the control of soil-borne phytopathogenic fungi, in the present study. Dual culture tests with Rhizoctonia solani and Fusarium oxysporum f. sp. lycopersici were used to conduct in vitro evaluation. In the presence of Trichoderma, phytopathogen’s growth rate was inhibited up to 59.70% for R. solani and 42.57% for F. oxysporum. Greenhouse trials with potted tomato plants demonstrated that Trichoderma caused a significant increase of stem height and fresh stem weight in pathogen-inoculated plants, compared with the negative control (plants artificially inoculated with the phytopathogen only). Except for T. simmonsii, plant growth was not significantly enhanced by a Trichoderma presence in the positive control (healthy plants). The overall performance of the two Trichoderma species studied was equivalent to that of the T. harzianum T22 commercial strain. All the tested species were found to be effective in suppressing colony growth and disease development of the soil borne pathogens in dual cultures and potted plants, indicating that they could be used as biocontrol agents. Our findings are discussed in the context of enhancing endophytic microorganisms’ application in crop production systems.
Aphids are among the most harmful crop pests, damaging plants by sucking sap or by transmitting pathogenic viruses. Plant infestation by aphids depends on their population growth. Entomopathogenic fungi are essential participants of terrestrial and aquatic ecosystems, regulating arthropod communities. Many fungal species with a symbiotic–endophytic relation with plants are pathogenic, producing insecticides or insect repellents. The present study investigated the effects of the fungal entomopathogens Beauveria bassiana, Metarhizium anisopliae and Isaria fumosorosea, following their endophytic colonization of the sweet pepper Capsicum annum, on the development of the green peach aphid Myzus persicae. After 21 days, B. bassiana produced 100% aphid mortality, M. anisopliae 90% and I. fumosorosea 83.3%. There were also significant differences in terms of the effect on aphid population in planta and on the survival time of young adults in planta. External mycelium appeared within 96 h after placing aphid cadavers on damp filter paper. PCR confirmed that the mycelium was of B. bassiana, M. anisopliae and I. fumosorosea. DNA sequences collected from this work were matched with existing sequences data in GenBank, using the Basic Local Alignment Search Tool. Our results showed that none of the three fungal isolates had an effect in promoting or suppressing the growth of C. annum.
Stored product pests can be detrimental to agricultural produce. As much as chemical pesticides are effective control agents, they involve several environmental and health risks. Within the framework of studies on alternative pest management methods, interest has focused on a plethora of plants whose extracts have demonstrated promising action as insecticides. Azadirachta indica and the derived neem oil have been extensively tested against many harmful insect species. In contrast, Cannabis sativa L. and its main compound, CBD, a highly concentrated cannabinoid, have not been investigated much. The present study examined the potential insecticidal activity of CBD and neem oils against 4th instar larvae of Tribolium confusum, Oryzaephilus surinamensis and Plodia interpunctella on wheat, rice and corn seeds. Treatment efficacy was expressed in terms of larval mortality. Mortality was observed in relation to dosage, time exposure intervals and product types. The results showed clear pesticidal activity for both oils, which at high doses induced significant mortality. The treatments produced significantly fewer offspring in the insect species tested than the control. The efficacy of treatment in progeny suppression was, as expected, dose dependent.
The insecticidal virulence of various entomopathogenic fungal isolates retrieved from soil samples was tested on adults of the granary weevil Sitophilus granarius (L.) (Coleoptera: Curculionidae). Bioassays were carried out in the laboratory where experimental adults were sprayed with 1 mL of conidial suspension (108 conidia/mL) from each isolate. Mortality was recorded at 7, 14, and 21 days after exposure. Mean mortality, mean lethal time, survival, and hazard effect were estimated for each isolate. Two isolates of Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae), one isolate of Aspergillus insuetus (Bainier) Thom & Church (Eurotiales: Trichocomaceae) and Metarhiziumanisopliae (Metschinkoff) Sorokin (Hypocreales: Clavicipitaceae) resulted in the highest mortality (97–100%). The isolates with both the highest hazard effect and the lowest survival rate were Aspergillus sp. and M. anisopliae. Our results indicate that entomopathogenic fungi have the potential to become a very useful tool in reducing chemical applications in storage facilities.
There is ample evidence that entomopathogenic fungi can be used as alternative biological control agents for the management of insect pests in storage facilities. As the market demands more environmentally friendly methods and chemical insecticides become increasingly obsolete, more studies are being conducted to evaluate new strains of entomopathogenic fungi for their efficacy in storage facilities. In this context, we tested ten species of fungi isolated from soil, belonging to the genera Cladosporium, Condenascus, Lecanicillium, and Penicillium, for their long-term effects on economically important beetle species. Whole wheat was directly sprayed with a conidial suspension of 108 spores/Ml of each of the tested fungi and then adults of Sitophilus granarius, S. oryzae, S. zeamais, Rhyzopertha dominica, and Trogoderma granarium were placed on the sprayed medium to study the mortality effects. Significantly higher mortality than the control was observed in all treatments. The lowest LT50 (9.164 days) was observed in T. granarium infected with Penicillium goetzii. The isolate with the strongest results was L. dimorphum, which recorded remarkably low LT50 values in S. oryzae (~11 days), R. dominica (~12 days), T. granarium (~10 days), and S. granarius (~13 days). However, for S. zeamais, it was more than 16 days. Our results confirm the existing literature on the efficacy of EPF on storage beetles, suggest the possible virulence of wild untested strains, and also highlight the importance of EPF specificity.