Cell wall active antifungal compounds produced by the marine fungus Hypoxylon oceanicum LL-15G256. III. Biological properties of 15G256 gamma.

15G256 gamma is a cyclic lipopeptide antifungal agent discovered in a mechanism of action screen for cell wall acting antifungal agents. The compound shows moderate activity in both greenhouse tests against plant disease caused by pathogenic fungi and in in vitro tests against human fungal pathogens. Microscopic examination of treated fungi suggests that the compound acts by the inhibition of cell wall biosynthesis. However, in vitro inhibition of Neurospora crassa glucan and chitin synthase were only observed at high drug concentrations suggesting that 15G256 gamma may act on a novel cell wall target.

Can synthetic pesticides be replaced with biologically-based alternatives?--an industry perspective.

Agricultural chemical companies have invested in the discovery and development of biological pesticides to complement synthetic pesticides for the control of insects, diseases, and weeds on agronomic and horticultural crops. For plant disease control, companies envisage biological fungicides entering markets where they have the best chance of performing and which are most receptive to using biological control methods. Fewer regulatory requirements can mean faster registration for a biological than a synthetic pesticide. However, industry's requirements for competitive performance, effective formulations, and economic production can mean significant investments in time and money for a biological pesticide, although total investment may be less than for a synthetic pesticide. One biocontrol project in which industry has invested is baculoviruses for insect control. Insect baculoviruses, genetically modified to kill insects faster than wild-type viruses, are attractive biocontrol agents because their selectivity to insect pests and safety to beneficial insects and mammals enable them to compete with synthetic insecticides. Industry is looking for similar biocontrol opportunities in disease control. Biocontrol agents for seedling disease, root rot, and postharvest disease control have been registered by the EPA and are trying to compete with synthetic fungicides for market share. To date, effective biocontrol agents have not been identified for the control of serious foliar diseases, such as grape downy mildew, potato late blight, wheat powdery mildew, and apple scab. Farmers must rely on synthetic fungicides and agronomic methods to control these diseases for the foreseeable future.