Physiological cross-resistance between DDT and lambda-cyhalothrin in the A. aegypti populations tested was dismissed. Physiological resistance to lambda-cyhalothrin appears to be associated with increased NSE. The differences in susceptibility levels and enzyme values among the populations were associated with genetic variations and chemicals in use locally.

Irrigated agriculture is a facing shortage of water and N in semiarid environments where these inputs are limiting factors for crop production. Experiments were conducted to optimize the water and N requirements for maize (Zea mays L.) under semiarid environmental conditions. Crop physiological and agronomics characteristics were evaluated for three irrigation regimes and five N fertilizer levels during 2009 and 2010. The experiments were conducted in a split‐plot design by triplicating water regimes in the main plots and N levels in the subplots. Total dry matter production and crop growth rate increased with an increase in the N application rate up to 300 kg ha−1 for all irrigation regimes. In contrast, maximum grain yield was achieved with application of 250 kg N ha−1. Polynomial analysis (third order) showed that 275 kg N ha−1 was optimum for grain yield at normal irrigation. Higher amounts of irrigation and N significantly increased water use efficiency (WUE). Since optimal N rates for maximum grain yield was 250 kg ha−1 with 525 mm irrigation water ha−1 during both growing seasons, this may be considered in formulating good agricultural practices for the soil and weather conditions resembling those of this study.

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