Susceptibility Of Stored African Yam Bean (Sphenostylis Stenocarpa) And Mung Bean (Vigna Radiata) To Levels Of Initial Infestation Of Callosobruchus Maculatus (Fabricus) (Coleoptera: Chysomelidae)

ABSTRACT

 African yam bean (Sphenostylis sternocapa) and Mung bean (Vigna radiata) are major pulses grown in Nigeria and other parts of the world for their high protein content. The effects of levels of initial infestation of Callosobruchus maculatus on S. sternocapa and V. radiata was evaluated under laboratory conditions (temperature of 28+2°C and relative humidity of 60+5%) at the Department of Zoology and Environmental Biology Laboratory of Michael Okpara University of Agriculture, Umudike from July to September, 2018. S. sternocapa and V. radiata seeds weighing 18g and 8g,respectively and bearing 0, 1, 2, 3 and 5 eggs was poured into 200 mls glass jars covered with muslin net and allowed for 30 and 60 days to develop to adults. The experiment was laid out in a completely randomized design (CRD) with four replicates. Results from data analysis showed that significantly (P < 0.05) higher number of adult C. maculatus emerged from batches bearing 5 eggs (14.25 and 8.25) at 60 DAI than others. Seed weight loss in varieties showed that significantly (P < 0.05) higher weight loss was recorded in S. sternocarpa bearing 5 eggs (39.28%) but those bearing 2 and 3 eggs (32.07% and 28.42%) were not significantly (P > 0.05) different from each other but were significantly (P < 0.05) different from 1 egg (25.09%) and control (0.00%). Meanwhile, weight loss in V. radiata was not significantly different (P < 0.05) from each other but was significantly different from control (0.00).