Weight loss caused by development of Sitophilus zeamais Motsch. in maize

Seventy single maize kernels were exposed to oviposition by Sitophilus zeamais. Weevils developed in 50 kernels, 16 yielding one adult, 24 two, 7 three, 2 four and 1 five adults. Weight loss of the kernels was observed throughout the developmental period, at 27°C 70% r.h. Development took a mean of 37 days resulting in adults with a mean weight of 3.1 mg. The overall mean loss in weight per grain was 18.3% or 52.1 mg and on average 2.0 insects emerged per kernel. The total consumption by an insect was 35.1 mg in grains with one emerging adult and approximately 25 mg for those with more than one. Half the total loss occurred between 13–24 days. An estimate of percentage weight loss was obtained by multiplying the percentage of damaged kernels by 0.12, 0.18 or 0.29 for kernels with 1, 2 or 3 emergence holes respectively. Frass weight was found to be of no use in estimating weight loss.