Table 2 The estimated duration of residual efficacy of insecticide treatments on different wall surfaces in two sites (Sekoru and Ziway) in Ethiopia, and the combined results, as determined by the number of months that the treatment resulted in greater than 80% mortality in 30 min cone bioassays using a susceptible Anopheles arabiensis strain

Rough mud

< 1

5

1

2^b

< 1

5

1

4

< 1

5

1

3

Smooth mud

< 1

6

1

5

< 1

6

< 1

2

< 1

6

< 1

5^a

Dung

1

5

4^a

7

2

4^a

2^b

6

1

4^a

2

7

Painted

4

5

4^a

7

4

4^a

4

6

4

4^a

4

6