CONTROL OF ARTIFICAL POPULATIONS OF THE DIAMONDBACK MOTH (LEPIDOPETERA: PLUTELLIDAE) ON COLLARD BY A NUCLEOPPLYTHEDROVIRUS WITH A STILLBENE-BASED ENHANCER AND AN ULTRAVIOLET LIGHT PROTECTANT.

Authors: Farrar, Robert; Shapiro, Martin

Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2005
Publication Date: 7/1/2005
Citation: Farrar, R.R., Shapiro, M. 2005. Control of artifical populations of the diamondback moth (lepidopetera: plutellidae) on collard by a nucleopplythedrovirus with a stillbene-based enhancer and an ultraviolet light protectant. Journal of Entomological Science. 40:280-290.

Interpretive Summary: The diamondback moth costs growers of cabbage and other cole crops some $1 billion dollars each year worldwide. This pest is becoming harder to control in many localities because it often becomes resistant to insecticides. New, environmentally friendly controls are thus needed for the diamondback moth. Previously, we tested in the laboratory a virus that kills diamondback moth caterpillars, as well as a few other types of caterpillars, but is harmless to other insects and vertebrate animals. Those tests were promising, so we tested this virus further in small field plots of collard. By spraying the virus onto infested plants, we were able to significantly reduce numbers of diamondback moth caterpillars. We previously found that certain fluorescent brighteners enhanced the activity of the virus. We were able to further reduce numbers of caterpillars in the field by adding a fluorescent brightener to the spray. Titanium dioxide, which protects viruses from sunlight, also improved control, at least in May and June, when sunlight was intense. We expect that other scientists developing better and safer ways to control the diamondback moth will use this information, as may private companies developing insect control products based on viruses. We will also use the information as a basis for further testing the virus in the field. We feel that this information will lead to improved insect control while also reducing insecticide use and the problems of environmental contamination and worker exposure.

Technical Abstract: The nucleopolyhedrovirus of the diamondback moth, Plutella xylostella (L.) (PxMNPV), was evaluated against artificial populations of this insect in small plots of collard, Brassica oleracea L. PxMNPV reduced numbers of larvae in all tests. Further reductions were obtained with the addition of a fluorescent brightener, Blankophor P167 in both tests in which it was included. The addition of an ultraviolet light protectant, photostabilized titanium dioxide to PxMNPV, also made a significant improvement, but only when the test was conducted in May and June. No effect of titanium dioxide was found when the test was conducted in September, when levels of solar irradiance were lower. Adding both materials together did not improve results relative to the addition of Blankophor P167 alone. No virus treatment, however, was as effective as the insecticide spinosad.