Location: Fruit and Tree Nut ResearchTitle: Enhanced biological control potential of the entomopathogenic nematode, Steinernema carpocapsae, applied with a protective gel formulation Author
|Dito, Danica - University Of California|
|Shapiro Ilan, David|
|Lewis, Edwin - University Of California|
Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/24/2016
Publication Date: 4/14/2016
Citation: Dito, D.F., Shapiro-Ilan, D.I., Dunlap, C.A., Behle, R.W., Lewis, E.E. 2016. Enhanced biological control potential of the entomopathogenic nematode, Steinernema carpocapsae, applied with a protective gel formulation. Biocontrol Science and Technology. 26(6):835–848.
Interpretive Summary: Due to environmental and regulatory concerns, alternatives to broad spectrum chemical insecticides are needed to develop sustainable pest management systems. Beneficial nematodes (also known as entomopathogenic nematodes) are commercially available bio-insecticides that are environmentally friendly. These nematodes are small round worms that kill insect pests but do not harm plants, pets, or humans and have little or no effect on other nontarget organisms. However, one major barrier to wider use of beneficial nematodes is their sensitivity to UV radiation and desiccation. As a result, applications of beneficial nematodes above-ground (where they may be subject to UV and desiccation) are severely limited. In a previous study, the authors demonstrated that a sprayable gel, Barricade®, can be applied on top of the nematodes to protect them from harmful environmental conditions and thereby improve insect pest control. Barricade® is a fire gel that is normally used to protect houses or other structures from wild fire. In this study, the use of Barricade® sprayable gel was explored further. The authors discovered that Barricade® can be applied at a lower concentration in a single combined spray with the nematodes; the single spray (using lower concentration of Barricade®) reduces the cost of the application and still protects beneficial nematodes from harmful environmental conditions. Moreover, the authors found that addition of common UV protecting agents, titanium dioxide or octyl methoxycinnamate (OMC) can further enhance the protective ability of Barricade®, and that the Barricade® formulation also improves the number of live nematodes retained on a leaf surface. This research advances knowledge on the usefulness and protective ability of sprayable gels, such as Barricade®, when combined with beneficial nematodes for improved biological pest control.
Technical Abstract: Entomopathogenic nematodes combined with the anti-desiccation gel, Barricade®, have potential as an effective pest management tool. We (1) ascertained whether Barricade® could provide protection to entomopathogenic nematode s at low concentrations when applied in direct sun, (2) determined if other ingredients added to Barricade® increased efficacy, and (3) quantified the retention and survival of entomopathogenic nematode s applied to foliage with Barricade®. Steinernema carpocapsae (All strain), were used for the experiments. After 60 minutes exposure to sunlight, entomopathogenic nematode s formulated in 1% Barricade® caused significantly higher G. mellonella mortality (60%) than all other treatments (2-37%). The desiccation and UV-protection provided by titanium dioxide (TD) and octyl methoxycinnamate (OMC) added to 1% Barricade® solution were tested in the laboratory and outdoors. Barricade® solutions at four concentrations, 0.25%, 0.50%, 1.00%, and 1.50% by volume and S. carpocapsae infective juveniles were added to the gel to reach a final entomopathogenic nematode concentration of 100 nematodes/ml. Barricade® with TD and Barricade® with OMC resulted in higher host mortality (43% and 25%) than all other treatments (2%-7%). After 8 hours in the greenhouse, the 0.25% anti-desiccant solution had the highest percentage of live nematodes retained on leaf surfaces. Our results show that Barricade® gel provides protection to entomopathogenic nematodes at substantially lower concentrations than previously tested. The ease of application with low concentrations of Barricade® gel, combined with the enhanced UV protection provided by OMC and TD, makes further research into specific applications of this formulation promising.