Occurrence and succession of insect pests of linseed under agro-climatic condition of Ranchi (Jharkhand).
Results of a field experiment conducted during 2002/03-2004/05 in Ranchi, Jharkhand, India, to determine the pest problems associated with linseed (Linum usitatissimum) cv. Neelum revealed that altogether twelve insect pests were observed to infest the crop at different stages of the crop growth. Among the pest species, Chrotogonus trachypterus, Oxya velox, Amrasca kerri [Empoasca kerri], Plusia orichalcea [Thysanoplusia orichalcea], Aphis craccivora, Macrosiphum sp., Nezara viridula and Spilosoma obliqua [Spilarctia obliqua] were appeared as stray pests whereas the termite, Microtermes spp., was considered as minor pest of linseed. The capsule borer, Helicoverpa armigera, was noticed during budding and reproductive stage of the crop which was responsible for damaging young buds and capsules of linseed and was placed under the category of major pest. Due to degree of severity and seriousness of the budfly, Dasineura lini, it was categorized as the key pest of the crop. The biotic agents regulating the pest population included a group of spiders (unidentified), the black ant Acantholepis simplex and the rove beetle Paederus spp. in the agroecosystem of linseed in the agroclimatic conditions of Ranchi.