BackgroundResidual efficacy of indoor residual spray may vary with different spray quality and wall surfaces types. This study evaluated the impact of spray quality and wall surface types on residual efficacy of propoxur against wild Anopheles gambiae sensu lato (s.l.) in southwest Ethiopia.MethodsThirty houses of different mud wall surfaces (10 smooth, 10 rough, 10 painted) were selected and randomly allocated into routine and standard spray. The routine spray was conducted by district health office as usual, while the standard spray was done by strictly following guidelines. Three control houses were selected from unsprayed nearby semi-urban. Wild An. gambiae s.l. were used for wall bioassay tests. Two-way mixed model analysis of variance was used to analyse the data. The mean variation between wall and spray types was compared by post hoc analysis of IBM SPSS version 20.ResultsOn standard spray, knockdown rate was 95.3% on painted, 82% on smooth and 72.5% on rough surface at week 17 of post-spray, whereas on routine spray it was 82.7% on painted, 48.7% on smooth and 60% on rough surface. On standard spray, mortality rate of An. gambiae s.l. was 99.3% on painted surface, 90% on smooth and 80% on rough surface. On routine spray, it was 89.3% on painted, 61.3% on smooth and 65% on rough surface at week 17 of post-spray. The painted wall surface showed the highest knockdown rate (86.4–100%) on standard and (73.8–91.5%) routine spray; mortality rate was more than 80% on both spray types during the 17 weeks of follow-up regardless of spray types. The lower mortality rate and residual effect was observed on routine smooth and rough wall surfaces. The residual efficacy of propoxur was > 80% at week 17 on standard spray regardless of the wall types and it was < 80% on routine spray except painted wall surface.ConclusionThe painted wall surface and standard spray showed better residual efficacy. Therefore, it is recommended to consider the wall surface available in the community to estimate the residual lifespan of the insecticide, and strictly to follow the spray guideline to improve the effectiveness of indoor residual spray.

In Ethiopia, although research on cotton improvement started as early as the mid 60`s, not much progress have been made to develop high yielding and quality fiber cotton varieties for production. Hence, the purpose of this work was to study the agronomic, yield and fiber quality performance of hybrid cotton varieties (YD-206, YD-203 and YD-211) along two local check varieties (Deltapine 90 and Stam 59A) for local registration and wider use. The experiment was carried out in a non-replicated single plot size of 10m x 10m across seven locations viz. Werer Agricultural Research Center, Amibara, Melkasedi, Gewane, Arbaminch, Shellie and Woyto. The results of this study indicated that, the three introduced hybrid cotton varieties gave higher seed cotton yield than the two local check varieties at all locations. Accordingly, the hybrid cotton varieties showed seed cotton yield advantage of 35.59% (YD-211), 35.54% (YD-206) and 29.43% (YD-223) over the best performed local check variety (Deltapine 90). Similarly lint yield and fiber length performances of the hybrids were superior to that of the local check varieties. Furthermore, agronomic and crop protection practices have to be determined to maximize production and productivity of these hybrids to ensure the profitability of the user and widen its acceptance.