Beneficial Soil Microbes Negatively Affect Spider Mites and Aphids in Pepper

Abstract

Beneficial soil microbes have long been recognized for their ability to improve plant growth, to antagonize pathogens and to prime plants against biotic stressors. Nevertheless, their ability to enhance plant resistance against arthropod pests remains largely unexplored, especially in crop plants such as pepper. Herein, we assessed the effects of several fungal and bacterial species/strains applied in the soil on the performance of key pests of pepper plants. Specifically, we recorded the impact of pepper inoculation with commercial strains of beneficial bacteria (Bacillus amyloliquefaciens and Pseudomonas spp.) as well as fungi (Trichoderma spp. and Cordyceps fumosorosea) on the population growth of the green peach aphid, Myzus persicae, and the two-spotted spider mite, Tetranychus urticae. Furthermore, we recorded the effects of microbial inoculation on plant growth parameters, such as stem and root weight. We found that both pests can be negatively affected by microbial inoculation: spider mites laid up to 40% fewer eggs, and the number of aphids were up to 50% less on pepper-inoculated plants, depending on the microbe. We also recorded a variation among the tested microbes in their impact on herbivore performance, but no significant effects were found on plant biomass. Our results add to the growing literature that beneficial soil microbes may be capable of exerting biocontrol capabilities against aboveground herbivorous pests possibly, among other means, via the elicitation of plant defense responses.

Plant-Mediated Effects of Beneficial Microbes and a Plant Strengthener against Spider Mites in Tomato

“…Nevertheless, the plant-mediated effects of other beneficial microbes such as plant-growth-promoting fungi (PGPF) or rhizobacteria (PGPR) on spider mites have been rarely addressed so far. An exception is the study of the beneficial soil endophytic fungus Fusarium solani strain K which was shown to negatively affect spider mite performance in tomato via the elicitation of plant defense responses [ 15 ], and different PGPR in strawberry [ 46 ], as well as the work of Pappas et al [ 47 ], who identified a series of effective beneficial fungi and bacteria against spider mites in pepper. With regard to the effects of arbuscular mycorrhizal fungi (AMF), previous studies have shown variable effects on spider mites.…”

Fungal Endophytes and Their Role in Agricultural Plant Protection against Pests and Pathogens

“…A tomato leaf detachment bioassay with B. bassiana -inoculated plants showed significant increases in mortality of TSSM depending on the inoculation method; mortality and leaf endophyte colonization frequency were mutually highest in sprayed leaves followed by soil drenching and seed soaking [ 178 ]. Commercial strains of Trichoderma asperellum , T. atroviride and Cordyceps fumosorosea applied as soil drench significantly reduced the number of TSSM and green peach aphid ( Myzus persicae ) on pepper ( Capsicum annuum ) [ 179 ].…”

Natuurvriendelijke bestrijding vanbladluizen in de glastuinbouw : Een overzicht van bestaande en nieuwe methoden van bestrijding

“…In paprika bleken diverse soorten micro-organismen in substraat, zoals Bacillus, Trichoderma en Isaria de weerbaarheid tegen bladluis te verhogen (Pappas et al 2021). Toepassing van dit soort micro-organismen voor plaagbestrijding valt onder de gewasbeschermingsmiddelenwet.…”