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

Table 3 Knock-down time and mortality rates of Anopheles arabiensis exposed to Deltamethrin 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	44.5	39.9–49.2	36.6	34.3–37.9	101.2	94.6–37.9	2.9
2	Rain	800	48.9	42.6–55.3	33.5	32.5–34.6	72.9	70.3–75.8	2.4
3	Dry	800	50.14	45.9–54.4	15.9	14.9–16.8	44.6	41.7–47.8	1.3
3	Rain	800	52.4	46.4–58.5	30.9	30.0–31.9	67.3	64.9–69.9	2.2
5	Dry	800	49.9	44.4–55.4	32.7	31.8–33.7	71.1	68.6–73.8	2.6
5	Rain	800	60.8	55.0–66.6	21.3	20.13–22.5	59.8	55.9–64.2	1.5
10	Dry	800	60.5	54.7–66.3	25.1	24.3–25.8	54.5	52.5–56.6	2.0
10	Rain	800	71.9	67.0–76.9	27.9	26.8–29.0	78.3	73.9–83.4	2.0
Control^a	Dry	800	100	–	12.5	–	19.8	–	–
Control^a	Rain	800	100	–	13.9	–	21.2	–	–

ISSN: 1475-2875