Effects of varietal resistance in soybean, Glycine max (L.) Merril. on life history and damage potential of Mirperus jaculus in a rainforest ecosystem of Southwest Nigeria

Abstract

Studies were carried out at Ago-Iwoye, Southwest Nigeria to determine the effects of host plant resistance in four promising soybean varieties on selected developmental parameters and damage potential of Mirperus jaculus both in the field and laboratory. The study was conducted at ambient conditions and 12:12 hour light: dark photoperiod. Results confirmed antibiosis as the mechanism in resistant cultivars and it caused total cessation of nymphal development at the first instar on TGX 923-2E and a significant prolongation of the developmental period (p<0.05) from egg to adult on TGX 849-294D (22%) followed by TGX 536-02D (13%) compared to TGX 996-28E, the susceptible control. However, there was no significant reduction (p>0.05) in percentage survival of immature stages on the varieties that supported development to adult compared to the control. The sex ratio averaged 1:1 on the three varieties that supported development. In the field, TGX 923-2E plots did show any visible sign of infestation during early and late planting seasons, an indication of field resistance.