Life table parameters of Callosobruchus maculatus on cowpea seeds (Vigna unguiculata) treated with some biological and chemical fertilizers

Abstract

The cowpea weevil, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae), a destructive insect pest of cowpea, Vigna unguiculata (L.), in the field and storage, causes significant losses in seed weight, germination ability, and the market value. The effect of cowpea (Mashhad cultivar) fertilization with chemical fertilizers (triple superphosphate (TSP) and urea) and some biofertilizers (Bradyrhizobium japonicum, Pseudomonas putida, mycorrhizal fungi) was studied on biology and life table parameters of C. maculatus at 28 ± 1°C, relative humidity of 65 ± 5%, and complete darkness. The highest immature survival (%) was on the grains treated with P. putida and control (97.75 and 95.69%, respectively), and the lowest survival was on the grains fertilized with TSP and B. japonicum (65.06 and 75%, respectively). Although the developmental time of C. maculatus reared on TSP- and B. japonicum-treated grains was longer than the control, the intrinsic rate of increase (0.124 day-1) and net reproductive rate (34.34 offspring) on the grains treated with TSP were lower than the control (0.143 day-1 and 51.07 offspring, respectively). Results of this research showed that the nutritional value of the grains obtained from TSP and B. japonicum treatments were lower than those obtained from other fertilizer treatments.

Keywords

• callosobruchus maculatus
• cowpea
• life history
• life table
• biofertilizer