The widespread adoption of cropping systems that are sustainable and environmentally friendly is vital for the macroeconomic
survival of civilization. Intercropping could ensure stability of insect populations in a system. A 3-yr (2005-2007) field trial
was therefore carried out in Nigeria under regular and ratoon crops to evaluate five recently developed pigeon pea (
Cajanus
cajan
[L.] Huth) genotypes (ICPL 87, ICPL 161, ICPL 85063, ICP 7120, and ICPL 87119) from the International Crops
Research Institute for Semi-Arid Tropics (ICRISAT) and one local variety for their relative performance and susceptibility
to insect pests. The pigeon pea genotypes were in a mixture with two maize genotypes (
Zea mays
L., open-pollinated and
hybrid) in regular crops for 2 yr (2005-2006) followed by a ratoon crop for 1 yr (2007). Termites (
Odontotermes badius
),
crickets (
Gymnogryllus lucens
), and variegated grasshoppers (
Zonocerus variegatus
) were the crop's seedling pests and
caused minimal damage.
Clavigralla spp. infestations were high at the reproductive stage causing 24% and 29% seed
damage in regular and ratoon pigeon pea crops, respectively. Maize slightly suppressed insect pest incidence and damage to
pigeon pea pods and seeds but significantly (P < 0.01) reduced grain yield in the regular pigeon pea crops in 2005 and 2006,
although not in the 2007 ratoon. The pigeon pea genotypes differed significantly (P < 0.05) in pest incidence at the podding
stage in both the regular and ratoon crops and in grain yield (P < 0.01) for the regular crop. Grain yield of the pigeon pea
ratoon crops was about 60% of the regular crop. Farmers were recommended to adopt the ICPL 161 and ICPL 87 genotypes
based on pest tolerance and high grain yield or as idiotypes in pigeon pea hybridization programs.
