[Estimation of the spectrum of the aerial dispersion of Bacillus thuringiensis].

The present paper estimates the number of viable spores of Bacillus thuringiensis per droplet and reveals the importance of this data to improve B. thuringiensis treatments. For a given diameter, droplets from Futura formula contained two times more spores than droplets from the formulas used to date. It is preferable to have B. thuringiensis droplets larger than those of chemical insecticides. A Grumman AgCat aircraft calibrated to give the desired larger droplets resulted in successful B. thuringiensis treatments.