Table 5.
Effects of Bacillus thuringiensis var. israelensis (Bactivec®) on densities of late instar of An. gambiae complex and percent reduction in “mosquito spheres” trials during three subsequent treatments (T) with varying doses
| Day | Average number per dip |
Percentage reduction |
|||||
|---|---|---|---|---|---|---|---|
| Late instars |
Late instars |
||||||
| Control | T1 | T2 | T3 | T1 | T2 | T3 | |
| 0a | 25.0 | 25.0 | 25.0 | 25.0 | – | – | – |
| 1 | 15.4A | 0.6B | 0B | 0B | 96.1 | 100 | 100 |
| 3 | 5.8A | 4.6A | 3.6A | 5.0A | 20.7 | 37.9 | 13.8 |
| 5 | 20.2A | 10.0A | 15.6A | 12.0A | 50.5 | 22.8 | 40.6 |
| 7 | 18.4A | 14.4A | 12.6A | 15.4A | 21.7 | 31.5 | 16.3 |
Note: In each row, larval density figures sharing the same superscript letter do not differ significantly.
Abbreviations: T1, minimum label rate (2 ml/m2); T2, maximum label rate (5 ml/m2); T3, twice the maximum label rate (10 ml/m2).
a
The first batch of 25 An. gambiae complex larvae were introduced in the treatment tubs and application of Bti; a new batch of 25 larvae were introduced on days 2, 4 and 6 (not shown).