Susceptibility of several cotton varieties to the cotton flea beetle, Podagrica puncticollis Weise (Coleoptera: Chrysomelidae), in a hot dry tropical environment of Ethiopia

Abstract

Field trials were conducted to determine the susceptibility of cotton varieties to infestation of cotton flea beetle, Podagrica puncticollis Weise (Coleoptera: Chrysomelidae). The experiment was carried out using twelve cotton varieties. The results showed significant differences among varieties in the populations of adult beetle they hosted and the injury they sustained 15, 22, 29, 36 and 43 days after sowing (DAS). Fifteen DAS, the highest number of adult beetle per plant (6.3), percent leaf area damaged (60.32 %) and number of shot-holes per attacked leaf (53.4) were recorded in Cucurova variety, whereas the lowest in Bulk-202 (2.05 beetles, 26.15% leaf area damaged and 23.16 shot-holes). The rate of incidence and damages decreased with the increase of the age of the cotton plants. The results showed significant differences among cotton varieties in some agronomic characteristics i.e. in number of plants counted per plot at harvest and seed cotton yield. Based on these findings, Cucurova, Local, Ionia and Acala SJ-2 varieties showed highly susceptible response, while Candia, Sille-91 and Deltapine-90 were moderately susceptible to cotton flea beetle. Bulk-202, Delcero and Claudia were the most tolerant varieties followed by CCRI-12 and Cuokra. These results will be valuable in the selection of cotton varieties to be used in areas where cotton flea beetle occurs.