Entomopathogenic nematodes induce systemic resistance in tomato against Spodoptera exigua, Bemisia tabaci and Pseudomonas syringae

Publication date: Available online 10 November 2015 Source:Biological Control Author(s): Ruisheng An, Diego Orellana, Larry P. Phelan, Luis Cañas, Parwinder S. Grewal Entomopathogenic nematodes (EPNs) Steinernema and Heterorhabditis are important biocontrol agents for soil-inhabiting insect pests in many high-value cropping systems. EPNs have also been shown to be antagonistic to plant-parasitic nematodes but the mechanisms are poorly understood. It has been recently discovered that soil application of EPNs can induce components of systemic resistance in hosta and Arabidopsis plants. Here, we hypothesized that EPN-induced systemic resistance is of broad spectrum with activity against chewing insects, sucking insects, and bacterial pathogens. We tested this hypothesis by comparing the development of beet armyworm Spodoptera exigua, sweetpotato whitefly Bemisia tabaci, and bacterial pathogen Pseudomonas syringae on EPN-treated and control tomato plants. Steinernema carpocapsae-infected waxworm cadavers were applied to the soil around tomato plants in pots whereas the control plants received freeze-killed waxworms. EPN-induced defense responses were evaluated at 3, 7 and 15 days after treatment (DAT). We observed that the EPN-treatment had significant negative impact on all three organisms on tomato leaves 3 or 7 DAT, but not 15 DAT. Treatment with EPNs delayed immature beet armyworms from reaching the next developmental stage, impaired whitefly egg hatch, and red...
Source: Biological Control - Category: Biology Source Type: research