Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 10, 2003
Publication Date: January 1, 2004
Citation: Farrar, R.R., Shapiro, M., Mcintosh, A.H. 2004. Fluorescent brighteners can enhance or inhibit the nucleopolyhedrovirus of the daimondback moth (lepidoptera: plutellidae). Journal of Entomological Science. 39:30-45. Interpretive Summary: The diamondback moth (DBM) is a major pest of cruciferous crops such as cabbage, broccoli, collard, and turnip. Worldwide, it causes annual losses in the billions of dollars. The situation is made worse by the fact that in many places, DBM has developed resistance to many chemical and microbial insecticides. Nucleopolyhedroviruses (NPVs) are naturally occurring viruses, each of which infects only specific species of insects or other arthropods. They are promising alternatives to pesticides for many important pests, especially caterpillars. While some NPVs have been known to infect DBM, none was particularly potent against it. We tested a recently discovered NPV of DBM, which was significantly better than other NPVs against DBM. We also found that it could be improved by the addition of a fluorescent brightener, Blankophor P167. Other brighteners, such as Blankophor HRS, however, inhibited this virus, which shows that care must be taken in selection of brighteners for use with viruses. These findings are expected to facilitate the development of the new NPV as an alternative control tactic for the diamondback moth. This can, in turn, reduce the use of chemical pesticides and problems of contamination, insecticide resistance, worker exposure, and residues in food.
Technical Abstract: The nucleopolyhedrovirus of the diamondback moth, Plutella xylostella (L.), (PxMNPV) was the most potent of three viruses tested against this insect. The potency of PxMNPV could be further increased by the addition of certain diaminostilbene disulfonic acid-derived fluorescent brighteners, including Blankophor P167 at a concentration of one percent. Other fluorescent brighteners, including Blankophor HRS at one percent, reduced the activity of PxMNPV, though lower concentrations of Blankophor HRS (one quarter to one half percent) enhanced activity. Blankophor HRS at one percent enhanced the nucleopolyhedrovirus of the celery looper, Anagrapha falcifera (Kirby), (AfMNPV) against the diamondback moth. Similar results were found in the corn earworm, Helicoverpa zea (Boddie), and the beet armyworm, Spodoptera exigua (Hübner), which are also susceptible to PxMNPV and AfMNPV. Consumption of foliage treated with Blankophor HRS did not differ from that of foliage treated with similar concentrations of Blankophor P167. These results indicate a negative effect of higher concentrations of Blankophor HRS on PxMNPV, rather than on the host insect.