TABLE 1.
Effects of spores on toxicity of B. thuringiensis crystals to resistant (NO-QA) and susceptible (LAB-P) diamondback moth larvae
| Strain | Sporesa | No. of larvae | Slope (SE) | LC50 (95% FL) (mg of protein/liter) | Spore effect ratiob | Resistance ratioc |
|---|---|---|---|---|---|---|
| B. thuringiensis subsp. kurstaki | ||||||
| LAB-P | + | 280 | 0.6 (0.1) | 0.3 (0.1–0.9) | ||
| − | 280 | 1.0 (0.1) | 2.9 (1.7–4.8) | 9.7 | ||
| NO-QA | + | 320 | 0.8 (0.2) | 360 (130–2,600) | 1,200 | |
| − | 280 | 0.5 (0.2) | 160,000 (8,200–4 × 1010) | 450 | 56,000 | |
| B. thuringiensis subsp. aizawai | ||||||
| LAB-P | + | 320 | 1.7 (0.3) | 0.9 (0.5–1.3) | ||
| − | 320 | 1.6 (0.2) | 1.3 (0.9–1.9) | 1.4 | ||
| NO-QA | + | 320 | 1.1 (0.2) | 2.9 (1.4–6.8) | 3.2 | |
| − | 320 | 1.3 (0.2) | 4.4 (2.6–7.6) | 1.5 | 3.4 |
a
B. thuringiensis subsp. kurstaki crystals were tested with (+) and without (−) B. thuringiensis subsp. kurstaki spores; B. thuringiensis subsp. aizawai crystals were tested with and without B. thuringiensis subsp. aizawai spores.
b
LC50 without spores divided by LC50 with spores for each strain.
c
LC50 for NO-QA divided by LC50 for LAB-P.