Previous studies led to the development of Bacillusthuringiensis formulations providing dispersion of the required 20 × 109 international units (IU) of B. thuringiensis in a final volume of 4.7 L/ha against spruce budworm. Although the use of these formulations was successful, it seemed essential to reduce their cost particularly by developing more concentrated formulations. Thus, a formulation (futura) providing dispersion of the same 20 × 109 IU in a final volume of 2.5 L/ha was developed. In 1979, the physical properties of this formulation were tested for dispersion and, in 1980, it was dispersed over five40-ha forest blocks infested with spruce budworm. The futura formulation showed the same possibilities as the preceding ones in terms of quality of dispersion, larval mortality, and foliage protection.

In a field trial two 100 acre (40 ha) plots of balsam fir heavily infested with spruce budworm were sprayed with a water-based formulation of a liquid concentrate containing 25% commercial Bacillusthuringiensis Berliner and 25% non-volatile additive. The spray formulation used on one plot contained 5.5 g of the enzyme chitinase added to the 200 gal (757 l) of material. The spray was applied at 2 gal/acre (G.P.A.) (18.6 l/ha) by a Stearman aircraft equipped with 4 Micronair® AU 3000 rotary atomizers. Spray deposits were sampled with paper cards and plates of nutrient medium. A dry dye treatment was used to enhance drop trace visibility on deposit sample cards.Larval mortality was higher on the chitinase treatment plot, and better foliage protection resulted. Biochemical tests indicated some differences in physiological responses in larvae and pupae from the two treatments. It is concluded that, given suitably equipped aircraft, and a guidance system that would ensure uniform coverage, the addition of chitinase should make it practicable as one of the methods of control of the spruce budworm.