Mortality (%)(a) and Repellency (%)(b) (Mean ± SE, n = 3) of Tribolium castaneum exposed to various plant extracts (Zingiber officinale, Syzygium aromaticum, Nicotiana tabacum and Azadirachta indica) at different exposure intervals. Plant extracts 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.