Compatibility of photoactive dyes with insect biocontrol agents

Integrated pest management (IPM) programmes often look for more specific wa ys to control pests Biological central agents such as the bacterium, Bacill us thuringiensis Berliner, and the fungus, Beauveria bassiana (Balsamo) Vui llemin, can control insects with minimal disturbance to the environment bec ause of their host specificity and short half-lives. Often these agents alo ne cannot pi event yield loss or are too expensive. This study looked at th e in vitro combination of these agents and photoactive dyes, especially phl oxine B (red dye D&C 28), a Food and Drug Administration approved dye, with the intent to provide better insect control. Photoactive dyes are being te sted for the control of many pest insects. Phloxine B and related xanthene dyes, eosin y, fluorescein and rose bengal inhibited the growth of both B. thuringiensis and B. bassiana Phloxine B was the most inhibitory and fluore scein the least inhibitory dye for both microbes. The magnitude of inhibiti on increased with increasing concentration of dye and light intensity. Ther efore, an adverse effect on the field performance of these biological contr ol agents in combination with xanthene dyes would be expected.