Management of Stalk Borers Using Sowing Date on Sorghum in Northeastern Ethiopia

Abstract

A sowing date study for the management of maize stalk borers on sorghum was conducted at two locations, Sirinka and Girana, in northeastern Ethiopia during 2003. Busseola fusca was important at Sirinka and Chilo partellus at Girana. The experiment was laid out in split plot using randomized complete block design with three replications. The treatments included six sowing dates at seven-day intervals starting from 27 June. Higher number of larvae before and after harvest was recorded in untreated than treated plots. Similarly, significantly high proportion of infested plants (46-74%), number of chaffy heads (25-26), infested peduncles (84-87%) and infested internodes (40-52%) were recorded in the early three sowing dates at Sirinka. Moreover, infestation and damage levels were lower in the late than early sowings at Girana. These parameters in general did not significantly vary among sowing dates in chemical
treated plots. There was no significant variation among sowing dates in grain yield at both locations. The lowest grain yield (34 q/ha) was obtained from sorghum sown on 11 July at Sirinka, while the highest yield loss of 13 q/ha (28%) occurred on sorghum sown on 4 July at Girana. In all sowing dates, grain yield losses due to stalk borer at Sirinka ranged 2-13 q/ha (5-28%) and at Girana 1-33q/ha (1-50%). The net benefit analysis showed that protection of sorghum by insecticide resulted in positive return. However, the amount of not return varied among different sowing dates in the range of 96-2057 Birr/ha at Sirinka and 1833.6-5359.6 Birr/ha at Girana.