Abstract
Stored grains are attacked by several insect pests. Tribolium castaneum (Herbst) and Trogoderma granarium (Everts) are
notorious stored grain insect pests. The present study was conducted to evaluate the insecticidal and growth inhibitory effects
of an entomopathogenic fungus Beauveria bassiana against two geographical populations of Trogoderma granarium and
Tribolium castaneum collected from Bahawalpur and Faisalabad districts of Punjab, Pakistan in 2015-2016. Homogenous
insect cultures of these populations were reared at optimum growth conditions (30±2°C and 65±5% RH). B. bassiana (RacerTM)
was applied at contraction of 0.3 × 108
, 0.6 × 108 and 0.9 × 108
conidia kg-1 of each diet (broken wheat grains and whole grains).
The 3rd instar larvae of both insects were released on fungus treated food medium and data regarding percent mortality were
recorded after 7, 14 and 21 days. The results indicate that T. castaneum larvae of Bahawalpur district showed maximum
mortality 57.35% at 0.9 × 108
conidial concentration of B. bassiana (RacerTM) followed by 50.61% larval mortality of
Faisalabad district insect population. The least larval mortality of T. granarium Faisalabad and Bahawalpur district was 4.47
and 4.48%, respectively at 0.3 × 108
conidia. In growth inhibition bioassays, maximum pupal and adult inhibition of T.
castaneum of Bahawalpur strain were 57.77% and 45.97%, respectively, whereas 40.67% and 38.67% inhibition in pupal and
adult emergence were recorded in case of Faisalabad strain of T. granarium. Overall results show that the mortality and growth
inhibition of test insects were found to be directly related to contraction and exposure time.
