The past problems associated with the use and application of microbial insecticide formulations are summarized. Effects of excessive weathering, sunlight, temperature, antimicrobiosis of host foliage and inadequate application are described as factors which impact field efficacy. Spray parameters to increase droplet deposition and reduce drift are discussed. Additionally, the 6 areas of active research at Abbott Laboratories to solve application and efficacy problems associated with microbial insecticides are listed. These are:
Development of liquid and powder formulations having long term biological and physical stability under reasonable storage conditions.
Investigation of the use of additives to reduce evaporation.
Development of methods to increase spray deposition by improving adherence and redistribution of the spray on foliage.
Improvement in the dispersion and suspendability of B. thuringiensis in spray tank mixes.
Increase of weatherability by addressing the problems of rain fastness, ultraviolet light degradation and antimicrobiosis.
Reduction of spray drift by exposing candidate formulations to a variety of application systems using controlled calibration procedures which adequately mimic the conditions under which the material will be applied. This includes calibration in different geographical regions from semiarid to subtropical.