Establishment of the entomopathogenic fungus Beauveria bassiana as an endophyte in Capsicum annuum and its effects on the aphid pest Myzus persicae (Homoptera: Aphididae)

Abstract

Introduction: Entomopathogenic fungi have been used as biological control agents of insect pests and have demonstrated a promising ability to colonize as endophytes a wide range of plant species. Objective: The aims of this study were to evaluate, in pepper plants, the most effective Beauveria bassiana inoculation techniques. In order to evaluate the presence of natural endophytes and its interaction with B. bassiana. Also to assess the effect of B. bassiana on the aphid Myzus persicae pepper leaf feeding preference and growth. Methods: Three inoculation techniques were evaluated: leaf spraying, seed immersion and root dipping. The pepper plants were inoculated with a conidia suspension adjusted to 1×108 conidia/ml. The presence of B. bassiana in the seedlings was evaluated at 7, 15 and 28 days after inoculation. Results: We found significant statistical differences between inoculation techniques. Foliar spraying showed the highest B. bassiana colonization frequency. The natural endophytes presented higher presence in the treatments in which B. bassiana had a low presence. This might indicate the occurrence of antifungal activity that interferes with the establishment of the entomopathogen in pepper tissues. We did not find statistical differences between inoculated and control pepper leaves with regard to the mortality and reproduction of the aphid pest M. persicae. However, the inoculation with B. bassiana showed a tendency to increase the mortality of adults and to decrease the offspring (nymphs). We did not find significant differences in the feeding preference between inoculated and control leaves, although there was a higher number of individuals on control leaves compared to those inoculated. Conclusions: The strain B. bassiana LPSC 1067 was established effectively as an endophyte in the pepper tissues. The most effective inoculation technique was leaf spraying. We did not find differences of statistical significance with regard to the mortality and reproduction of the aphid pest M. persicae. However, the inoculation with B. bassiana showed a tendency to increase the mortality of adults and to decrease the offspring (nymphs). Future studies evaluating the indirect effects of endophytic entomopathogens on both plants and herbivorous insects are needed to further explore their potential use in the management of insect pests.

Direct and Indirect Effect via Endophytism of Entomopathogenic Fungi on the Fitness of Myzus persicae and Its Ability to Spread PLRV on Tobacco

“…These studies provided evidence that B. bassiana was also indirectly effective against aphids via endophytism. Even if Allegrucci et al [81] did not find significant aphid mortality differences on pepper (Capsicum annuum L.) endophytically colonized by B. bassiana and control plants, aphids more numerously died on B. bassiana-inoculated plants. Such an increased mortality in aphids settled on endophytically colonized plants was previously attributed to a possible improvement in plant resistance conferred by EEPF [27,95].…”

“…The effectiveness of B. bassiana as a biological control agent against phloem-feeding insects and especially aphids are well-known and widely documented [21,26,28,30,[80][81][82][83][84][85][86]. The most common treatment method use in the field and in the laboratory is the direct contact between the EPF spores and the insect pest [87][88][89][90].…”

“…However, the plant protective duration by EEPF against the virus would have been limited. Indeed, the colonization rate of plant tissue decreased with time [81] depending on several factors, including the inoculation method, fungal isolate, plant species, and environmental conditions [36,46,47]. For instance, in tobacco, tissue colonization by B. bassiana inoculated by the foliar spray method dropped from 100 to 20% twenty days after inoculation [47].…”

Uso de extractos botánicos para el control de pulgón (Myzus persicae: Aphididae) y mosca blanca (Bemisia tabaci: Aleyrodidae) en el cultivo de pimiento (Capsicum anuum: Solanaceae), en Ecuador

“…Los daños que ocasionan los pulgones, mosca blanca y ácaros en el pimiento se deben al tipo de aparato bucal que poseen, tienen la capacidad de succionar la sabia de hojas, f lores y frutos; producen manchas cloróticas, manchas oscuras o rojas, amarillamiento, abscisión prematura de las hojas infestadas, estrés hídrico; marchitamiento, reducción del crecimiento, maduración irregular del fruto, por lo que, la calidad y el rendimiento de los cultivos es afectado (Xue, Wang, Bi, Li y Liu, 2010;Mao y Zeng, 2013;Fonte, Garcerá, Tena y Chueca, 2019). Adicionalmente, muchas especies de las antes mencionadas son consideradas importantes vectores de virus en el cultivo de pimiento y otras hortalizas (Castresana y Puhl, 2018;Allegrucci et al, 2020;Fortes, Fernández y Moriones, 2020).…”

Journal of Plant Protection Research

“…Recently, some publications have shown that the establishment of B. bassiana as an endophyte in pepper improved several plant growth parameters and had a controlling effect against the insect pest Myzus persicae (Hemiptera: Aphididae) and the fungal disease caused by Botrytis cinerea Pers. (Helotiales: Sclerotiniaceae) (Jaber and Araj 2018;Allegrucci et al 2020;Barra-Bucarei et al 2020).…”