Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/1996
Publication Date: N/A
Interpretive Summary: Two of the main constraints to the use of some baculoviruses as insect control agents are their relatively low activity and lack of persistence after application. Recently fluorescent brighteners, commonly used to "brighten" white clothing, were found to both enhance viral activity and increase virus persistence. We tested the ability of one brightener, M2R, to enhance the activity of a nuclear polyhedrosis virus isolated from the celery looper when fed simultaneously to larvae of the cabbage looper, beet armyworm, tobacco budworm, and corn earworm, all important agricultural pests. Activity of the virus was enhanced from 2.9 to 16 fold depending on the species challenged. Time to 50% mortality was also reduced when an optimum concentration was used. Although enhancing virus activity, 1% M2R also inhibited feeding by neonate larvae. The importance of these findings are discussed in relationship to the use of M2R as an adjuvant for viral insecticides.
Technical Abstract: The influence of Calcofluor M2R (=Tinopal LPW = fluorescent brightener 28), a fluorescent brightener, on the activity of a nuclear polyhedrosis virus (AfMNPV) isolated from the celery looper Autographa falcifera (Kirby) was determined. The species challenged with and without M2R included Heliothis virescens (Fabricius), Helicoverpa zea (Boddie), Spodoptera exigua (H¿bner), and Trichoplusia ni (Hubner), all economically important pest species of a number of food and fiber crops. Levels of synergism as determined by LC50 values varied from 2.9 to 13.6-fold while LD95 values ranged from 3.7 to 16-fold, depending on the species. The greatest synergism occurred among T. ni larvae. LT50 values were significantly affected particularly when lower concentrations of polyhedra were fed. The presence of M2R reduced LT50 values up to 2.1-fold among the species tested. The optimum concentrations for M2R enhancement were between 0.25 and 1% (wt/vol). Choice tests between water and M2R treated diet showed that larvae preferred non-M2R treated diet. The implications of these data for use of M2R as an adjuvant for AfMNPV and other baculoviruses are discussed.