Laboratory evaluation of six improved cowpea Vigna unguiculata varieties for susceptibility to seed beetle, Callosobruchus maculatus (Coleoptera: Chrysomelidae) in Storage

Laboratory experiments were carried out to evaluate the susceptibility of six improved cowpea varieties to seed beetle, Callosobruchus maculatus (Coleoptera: Chrysomelidae) attack at a temperature of ۲۹ ± ۲ °C and a relative humidity of ۶۵ ± ۳%. Fifty grams of each variety were weighed in Kilner jars (۲۵۰ml) and infested with three females and two males of C. maculatus that were ۱-۲ days old. Data recorded were the physical characteristics of the cowpea varieties, number of eggs laid, percentage egg survival, number of emerged adults, duration of emergence (DE), mean developmental period (MDP), percentage seed weight loss, percentage seed damage and susceptibility index. The experiment was a completely randomised design with three replications. Results showed that significant differences (p < ۰.۰۵) existed in DE and MDP among the cowpea varieties studied. IT۹۰K-۷۶, IT۹۸K-۱۳۱, IT۱۱D-۱۵-۲۱ and IT۰۷K-۲۹۹-۶ performed significantly better in duration of emergence than IT۱۰K-۸۶۶-۱ and TVx ۳۲۳۶. IT۹۸K-۱۳۱-۱ performed significantly better in median developmental period (۲۶.۶۷ days) than other varieties except for IT۹۰K-۷۶ (۲۲.۶۷ days). Results showed that IT۹۰K-۷۶, IT۱۰K-۸۶۶-۱ and IT۹۸K-۱۳۱-۱ were moderately resistant while IT۰۷K-۲۹۹-۶, IT۱۱D-۱۵-۲۱ and TVx ۳۲۳۶ were susceptible. This study recommends IT۹۰K-۷۶ because it performed appreciably better in these parameters than the other cowpea varieties when infested with C. maculatus in storage.

کلیدواژه ها:

Grains ، insect activity ، non-chemical control ، resistance ، storage ، بذور انباری ، فعالیت حشره ، کنترل غیرشیمیایی ، مقاومت ، انبار