Mortality (%)(a) and Repellency (%)(b) (Mean ± SE, n = 3) of Tribolium castaneum exposed to various doses (20mg, 40mg, 60mg and 80mg) of plant extracts (Zingiber officinale, Syzygium aromaticum, Nicotiana tabacum and Azadirachta indica) at different exposure intervals. Extract doses are on x-axis and measured variables are on y-axis. DEI = Days exposure interval; HEI = Hours exposure interval; Means with different letters are significantly different (P < 0.05), Bonferroni test, comparisons across all treatments.