The influence of age on insecticide susceptibility of Anopheles arabiensis during dry and rainy seasons in rice irrigation schemes of Northern Tanzania

Table 1 Knock-down time and mortality rates of Anopheles arabiensis exposed to DDT for a period of 60 min in dry and rainy seasons

Age (days)	Season	Number tested	24 h mortality	95% CI	KDT₅₀	95% CI	KDT₉₅	95% CI	KDT₅₀ ratio (RR)
2	Dry	800	100	–	24.5	23.8–25.3	46.1	44.4–47.9	1.3
2	Rain	800	100	–	26.8	22.7–31.6	52.8	44.2–64.7	1.7
3	Dry	800	100	–	27.2	26.2–28.2	51.2	49.1–53.4	1.5
3	Rain	800	100	–	28.4	25.1–32.1	55.8	48.4–66.4	1.8
5	Dry	800	100	–	22.58	21.8–23.4	42.5	40.8–44.4	1.2
5	Rain	800	100	–	26.7	23.5–30.4	52.7	45.6–62.5	1.7
10	Dry	800	100	–	25.3	24.5–26.2	47.7	47.8–49.7	1.4
10	Rain	800	100	–	25.4	22.4–28.9	50.1	43.3–59.5	1.6
Control^a	Dry	800	100	–	18.2	–	23.7	–	–
Control^a	Rain	800	100	–	15.9	–	21.3	–	–

ISSN: 1475-2875