Influence of Physical and Chemical Properties in Grains of Different Maize Genotypes on Biology of Sitotroga cerealella (Oliv.) (Lepidoptera: Gelechiidae)

Abstract

Laboratory experiment was undertaken to study biology of Sitotroga cerealella on
five maize genotypes, viz. non-quality protein maize, quality protein maize
(QPM), sweet corn, pop corn and local maize. The data on insect biology, grain
physical and chemical characteristics were recorded. Results showed that S
cerealella reared on the sweet corn displayed the longest larval-pupal period (27.0
d). developmental time (42.67 d), longevity o f adult moth (10 days for female and
6.67 for male), egg hatching period (5.67 d) and the lowest survival percentage
(25.5%) and fecundity (87.83 eggs/female). On the contrary, QPM displayed the
shortest larval-pupal period (21.17 d), developmental time (34.83 d), longevity o f
moth (6.50 days for female and 3.83 for male), egg hatching period (3.83 d) and
the highest fecundity (140.38 eggs/female). Correlation coefficients between
insect biology and grain physfcochemical characteristics were calculated, yielding
a clear relationship between grain hardness, grain size, kernel weight, crude fat,
amylase, phenolic, and insect developmental traits. The harder and smaller size
kernels in combination with reduced fat content and increased amylase and
phenolic concentration had resulted in poor insect performance. These results
indicated that a single physical or chemical characters alone are not responsible
for suitability o f grain to S. cerealella unless combined together. Our study leads
to the conclusion that biology o f S. cerealella was related to the combined effect
of kernel physical and chemical characteristics.