Field evaluations of pigeon pea genotypes for resistance against pad borers
The Journal of Agriculture of the University of Puerto Rico
Two field plantings were established at Isabela (AES-UPR) (27 August 1984) to evaluate 27 genotypes (15 early bloomers and 12 late bloomers) for resistance to pod borer, Heliothis virescens and Etiella zinckenella. One planting of the 27 genotypes was treated with methomyl 90S (0.56 kg/ha). The second planting was untreated, insecticide applications began at the flowering stage. The efficacy and resistance data were based on the number of larvae and damaged pods per plot at harvest. Eggs of H.
... arvest. Eggs of H. virescens per pod per plot were counted. None of the untreated early bloomers tested were free from pod borer attack. The most tolerant genotypes were lines 82-26-1 and 82-1-24 Ponce 83, with 19 and 28% damaged pods, respectively. The most susceptible was line 69-73-1 -B-D with 57% damaged pods. At harvest, genotypes 82-3-16, 29 Irradiado, 79 Irradiado, 99-1 Irradiado and 69-73-1-B-D were free or almost free of E. zinckenella larvae. Methomyl-treated early bloomer genotypes showed lower percentages of infestation. Line 69-73-1-B-D showed only 7% damaged pods. The most susceptible, with 55% damaged pods, was line 82-29. All the untreated late bloomer genotypes were attacked by pod borer larvae. Lines 69-68 and 7 had the best ratings with 21 and 24% damaged pods, respectively. Cultivar Amarillo Kaki was the most susceptible, with 57% damaged pods. At harvest, H. virescens larvae was more dominant except for lines 87-7 Ponce 83 and cv. Santa Isabel, where E. zinckenella larvae were more abundant, Methomyl-treated plants of the late bloomers showed lower percentages of damaged pods. Line 12 and cv. Amarillo-Kaki 1 each showed 11 % damaged pods. Cultivar Santa Isabel and lines 82-7 Ponce and 77-1 Irradiado were the most susceptible.