Effect of Sowing Date on Noug Leafminer in Northwestern Ethiopia

Abstract

Recent surveys in northwestern Ethiopia showed that the noug leafminer Sphaeroderma guizotiae (Selman) (Coleoptera: Chrysomelidae) is an increasingly destructive pest o f noug (Guizotia abyssinica). In an attempt to develop an integrated pest management programme against this pest we conducted a sowing date experiment. Five dates, at 10-day intervals were used beginning on May 30 at Adet Research Centre during the 1994 and 1995 cropping seasons. Results o f this experiment showed that infestation levels ranged between 11 and 35 percent, depending on the season. Infestations increased and yields decreased significantly as the sowing date was delayed. Leaf area damage ranged between 23 and 45 percent, the highest record being observed in last (July 14) sown plots. Planting noug at the beginning o f June at Adet has an advantage to reduce the pest attack and obtain increased yield.