Abstract:

Eurystylus oldi (Poppius) which was considered to be a minor pest of sorghum, is now a real constraint to sorghum production in West and Central Africa. Field and laboratory experiments were conducted at Samaru (Zaria) on the insect’s biology, population dynamics, host range and dry season survival, as well as to screen several sorghum cultivars for sources of resistance. Sorghum cultivars NR 71213 and ICSH 89009 NG were tolerant of E. oldi, with reference to grain yield, 1000-grain weight and floaters. Pre-oviposition period for female insects was 6+0.63 days. Eggs hatched after 4.25±0.5 days (for males) and 4.83±0.75 days (for females). There were five nymphal instars on sorghum. Mean longevity from egg to adult was 50±5.03 days for males and 50+3.33 days for females. Adult insects mated around 6 a.m. In 1994 and 1995, the population of E. oldi nymphs and adults peaked in the last week of September. Pigeon pea was found to be an alternative host of the insect.