From Diverse Origins to Specific Targets: Role of Microorganisms in Indirect Pest Biological Control

Abstract

Integrated pest management (IPM) is today a widely accepted pest management strategy to select and use the most efficient control tactics and at the same time reduce over-dependence on chemical insecticides and their potentially negative environmental effects. One of the main pillars of IPM is biological control. While biological control programs of pest insects commonly rely on natural enemies such as predatory insects, parasitoids and microbial pathogens, there is increasing evidence that plant, soil and insect microbiomes can also be exploited to enhance plant defense against herbivores. In this mini-review, we illustrate how microorganisms from diverse origins can contribute to plant fitness, functional traits and indirect defense responses against pest insects, and therefore be indirectly used to improve biological pest control practices. Microorganisms in the rhizosphere, phyllosphere and endosphere have not only been shown to enhance plant growth and plant strength, but also promote plant defense against herbivores both above- and belowground by providing feeding deterrence or antibiosis. Also, herbivore associated molecular patterns may be induced by microorganisms that come from oral phytophagous insect secretions and elicit plant-specific responses to herbivore attacks. Furthermore, microorganisms that inhabit floral nectar and insect honeydew produce volatile organic compounds that attract beneficial insects like natural enemies, thereby providing indirect pest control. Given the multiple benefits of microorganisms to plants, we argue that future IPMs should consider and exploit the whole range of possibilities that microorganisms offer to enhance plant defense and increase attraction, fecundity and performance of natural enemies.

Identification and application of bacterial volatiles to attract a generalist aphid parasitoid: from laboratory to greenhouse assays

“…These chemicals can be sprayed onto crops or deployed in dispensers at regular intervals in the cropping system 5 . While most research in this field has focused on cues derived from plants and insects, 4,7 there is mounting evidence that microorganisms emit volatile compounds (mVOCs, microbial volatile organic compounds) that also play a role in insect behaviour 8–11 . In some cases, mVOCs attract insects by signalling the presence of appropriate resources such as food sources and oviposition sites, 12–14 whereas others have been found to deter insects 15 .…”

Essential Oil-Based Bioherbicides: Human Health Risks Analysis

“…As pesticides aim to destroy pests, they have toxicity for some organisms, but a major drawback is that this toxicity may also affect non-targeted organisms (for example, soil microfauna or pollinator insects) [32].…”

Identifying the Gut Virome of Diaphorina citri from Florida Groves

“…Unfortunately, these chemical-based methods are often ineffective because they are non-specific, costly, environmentally unfriendly, and lead to insecticide resistance [ 11 , 12 , 13 , 14 ]. Therefore, biological control has been studied and considered to be an effective, specific tool for controlling insect vectors [ 15 , 16 , 17 ]. The introduction of entomopathogens as a biological control was studied and practiced in fungi, bacteria, viruses, and protozoa [ 18 ].…”