Biopesticide synergy when combining plant flavonoids and entomopathogenic baculovirus

Abstract

four crop plants known to be hosts for the lepidopteran Trichoplusia ni (soybean, green bean, cotton, and cabbage) were treated with the biopesticide AfMNPV baculovirus in a dosage response assay. Treated soybean had, on average, a 6-fold increase in virus activity compared with the other crops. Leaf trichomes on soybeans were not found to be responsible for the observed increase of insecticidal activity. Three flavonoid compounds (daidzein, genistein, and kaempferol) were uniquely found only in the soybean crop, and were not detected in cotton, cabbage, or green bean plant matter. The individual flavonoid compounds did not cause T ni. mortality in no-virus assays when incorporated into artificial insect diet. The combination of the three flavonoid compounds at leaf level concentrations significantly increased baculovirus activity in diet incorporation assays. When the daidzein, genistein, and kaempferol were added to artificial diet, at 3.5-6.5 × leaf level concentrations, virus activity increased 1.5, 2.3, and 4.2-fold for each respective flavonoid. The soybean flavonoid compounds were found to synergistically improve baculovirus activity against T. ni.Biological control has been defined as the use of predators, parasites, or pathogens to manage crop pests in a highly specific and environmentally friendly method 1 . The development of microbial-based biopesticides represents the augmentation of biological control for insect pests of plants and is increasingly viable as a commercial control tactic. The use of naturally occurring biological control agents allows growers to precisely target a pest population 2 . Research on this topic often focuses on the interaction specifically between the pathogen and target insect, such as the control efficacy provided by the application of a biopesticide. However, plants primarily protect themselves through the production of chemical defense compounds, which may alter aspects of this pest/pathogen interaction 3 . In a natural forest ecosystem, plant chemistries contribute to complex interactions depending on many parameters of the particular ecosystem, such as the density of oak trees in a forest 4 . Although comparatively less complex, reports of interactions among crop, pest, and pathogen vary for monoculture cropping systems. The susceptibility of Helicoverpa zea to Helicoverpa zea nucleopolyhedrovirus was found to be greater when fed on soybean rather than cotton, however, no specific plant chemistry was identified 5 . In okra and tomato, induced plant defense chemistries are correlated with reduced baculovirus infection of the lepidopteron Heliothis virescens (Fabricius), however induced systemic acquired resistance in cotton foliage had no effect on baculovirus infection of the lepidopteron Helicoverpa armigera (Hübner) 6,7 .A naturally occurring baculovirus was isolated and incorporated in an integrated pest management system in Brazil, which successfully controlled the soybean defoliating lepidopteran velvet bean caterpillar, Anticarsia gemmatalis Hübner 8,9 . Another...

Swietenia mahagoni Leaves Extract: Antifungal, Insecticidal, and Phytochemical Analysis

“…Sequential binding of multiple molecules of caffeic acid was shown to possess a potent inhibitor of Helicoverpa armigera Hubner gut proteases' activity and gene expression [56]. Ultimately, some of the moieties of the SMAL extract might share only a synergistic action, for instance, the synergistic effects of the derivatives of chlorogenic acid on quercetin [55], vanillin mixtures with imidacloprid or α-cypermethrin [57], and daidzein on the baculovirus biopesticide [58]. Moreover, the hesperidin-Mg complex was found to be a trigger for the insecticide's potential against the adults of Bemisia tabaci Gennadius and Spodoptera frugiperda (J.E.…”

Insecticidal Activity of Organic Extracts of Solidago graminifolia and Its Main Metabolites (Quercetin and Chlorogenic Acid) against Spodoptera frugiperda: An In Vitro and In Silico Approach

“…This inhibitory activity of chlorogenic acid has also been described in vivo [ 18 , 19 ]. Quercetin and kaempferol have been described as the main metabolites of S. virgaurea L. (European goldenrod, Woundwort) [ 6 ]; both metabolites have antioxidant activity [ 20 , 21 ]. A high insecticidal activity has been described for quercetin and other flavonols that act as AChE inhibitors, and their possible mechanism of action is associated with the interactions that occur between the flavonol skeleton and the catalytic residues Asp74 or Tyr72 [ 22 , 23 ].…”

Quantitative Study on Anti-Pest Activity of Natural Products Based on Visualization Framework of Knowledge Graph

“…Structurally, they are composed of two benzene rings, connected by an oxygen-containing heterocycle [86] . Flavonoids have antiallergic, anticancer, antioxidant, antibacterial and antiviral properties, and are widely used as insecticides [87][88][89] to control a variety of insect pests, such as P. xylostella, aphids, locusts and tobacco mosaic virus [90][91][92][93] .…”