Application of broad-spectrum pesticides is the primary method used for controlling fungal and insect pests. Such application has resulted in significant environmental pollution and ecological disruption. Pesticide residues are found in food and groundwater and often eliminate beneficial organisms resulting in emergence of secondary pests. Furthermore, as the target pests become less susceptible to the pesticide, there can be a resurgence of the original pest, requiring application of excessive quantities of pesticides for control.
A number of strategies for biological or biorational control of fungal and insect pests have been envisioned. Among the more attractive strategies are those that target an attribute that is pest specific. One target that has been selected is the structural polymer chitin, which is present in insects and some fungi that attack plants, but is absent in higher plants and vertebrates. U.S. Pat. No. 4,751,081 follows this approach and is directed to novel chitinase-producing bacteria strains for use for inhibiting chitinase-sensitive plant pathogens (fungi and nematodes). The approach of U.S. Pat. No. 4,751,081 lacks flexibility.