Important insect pests of onion in Sokoto, Nigeria

Production of vegetables is a major activity of farmers in northern Nigeria, in dry season.The biggest threats to realization of profit is that of insect pests, particularly thrips on onion. Farmers know the importance of early planting and chemicals, they may however not quantify loss or profit if onion is planted at different months of the year and the best chemical to use and when the two are combined. The book gives information on the yield obtained at monthly sowing of onion, and when this is combined with lambda-cyhalothrin. Results show that Thrips tabaci (Thysanoptera: Thripidae) was the dominant insect pest attacking onion and is capable of reducing bulb yield when planting was late in December. Other minor insect pests are Zonocerus variegatus and Spodoptera exigua. Late onion harbours 600 thrips per plant, with third youngest leaf harbouring the highest population, irrespective of age of the crop.Planting in November and March produced 47.7 and 1.5 tons/ha, respectively. Lambda-cyhalothrin at 745 ml/ha gave yield advantage of 7.16 tons/ha over the untreated. The book is intended for farmers growing onion in tropical countries, particularly in the hot season.