Effects of temperature and photoperiod on development and oviposition of the legume flower thrips, Megalurothrips sjostedti

Megalurothrips sjostedti is an economic pest of cowpea in tropical Africa. There are no reports of the effect of temperature on the development of the pest and no diapause has been detected. The developmental rate and reprodu ction of M. sjostedti was studied under six constant temperatures (14, 17, 20, 23, 26 and 29 degrees C) and a photoperiod of L12:D12 in the laboratory . Total developmental time ranged from 33.1 days at 14 degrees C to 19.2 da ys at 26 degrees C. At 29 degrees C, all larvae died during hatching. Egg, larval and pupal stages required 94.3, 97.1 and 105.3 deg-days (DD) above a threshold of 8.2, 9.1 and 10.4 degrees C, respectively, to complete develo pment. Total developmental cycle was completed at 163.9 DD above a threshol d of 12.6 degrees C. Adult longevity was lowest (11.1 days) at 29 degrees C and highest (28.7 days) at 14 degrees C. At constant temperatures, the hig hest pre-oviposition period was observed at 29 degrees C under a photoperio d of L16:D8. Egg production also ceased at this temperature/photoperiod com bination. Total fecundity was highest at 26 degrees C under L10:D14. At cyc lical temperatures, pre-oviposition period was longest (12.4 days) at 20/29 degrees C under L16:D8. Total fecundity was highest (168.4 eggs) at 14/26 degrees C under L10:D14, and lowest (8.2 eggs) at 20/29 degrees C under L16 :D8. The significance of these findings in the management of M. sjostedti i s discussed.