OBSERVATIONS IN KENYA ON FLIGHT ACTIVITY OF STORED PRODUCTS INSECTS PARTICULARLY SITOPHILUS ZEAMAIS MOTSCH

The periodicity and intensity of the flights of stored products insects at various sites out of doors on farms in the West Kenya Highlands was assessed using a suction trap. The following insects were caught: Cadra cautella, Sitotroga cerealella, Carpophilus dimidiatus, C. fumatus, C. obsoletus, Cryptolestes ferrugineus, C. pusillus, C. ugandae and other Laemophloeinae, Oryzaephilus surinamensis, Sitophilus zeamais, Tribolium castaneum and Typhaea stercorea. In S. zeamais, which was the most common, the flight periodicity curve had a peak at between 15.00 and 17.00 hours. The intensity depended upon the numbers present and climatic factors, particularly the temperature at 15.00 hours and the amount of sunshine between 13.00 and 18.00 hours, although other related climatic factors should not be overlooked. The practical significance of these findings is discussed. Periodicity in four other species, Cadra cautella, Sitotroga cerealella, Tribolium castaneum and Typhaea stercorea is also described. Attempts to determine the flight range of Sitophilus zeamais were disappointing but it was shown that the distance can be at least a quarter of a mile. The practice of growing seed maize at least half a mile from any store appears to have resulted in a significant decrease in the rate of field infestation. © 1969.