Maruca vitrata (Fabricius) (Lepidoptera: Crambidae): comparative infestation and seasonal population fluctuations on different pigeonpea genotypes in Punjab, India.

Maruca vitrata (Fabricius) (Lepidoptera: Crambidae) is a serious threat to grain legumes, particularly pigeonpea. Varietal resistance in pigeonpea against M. vitrata and knowledge about the seasonal abundance of the pest are crucial to manage it efficiently. Nine pigeonpea genotypes (AL 1932, AL 2000, AL 1747, MN 1, AL 2102, PADT16, AL 201, PAU 881 and AL 882) were screened against M. vitrata under field conditions for two years (Kharif 2020 and 2021). M. vitrata larvae were first observed during the 36th SMW (Standard Meteorological Week) in the early flowering genotypes (MN 1 and PADT 16). The pest population gradually reached its peak during the 40th SMW on all the genotypes and gradually declined thereafter, with no pest population after the 43rd SMW. Mean larval population, web counts and per cent pod damage were the lowest in genotype AL 1747 and the highest in genotype MN 1. The number of larvae and webs per plant had a non-significant correlation with all the weather parameters. Principal component analysis (PCA) was used and the variables were transformed into principal components (PC) to explain the nature and extent of the relationships among different variables. During kharif 2020, PC1 and PC2 between M. vitrata larvae, webs and weather parameters captured 53.0 and 34.9 per cent of the variability in data, respectively whereas during kharif 2021, PC1 and PC2 captured 49.0 and 35.8 per cent of the variability in data, respectively. Our results show that genotype AL 1747 consistently performed better under M. vitrata infestation and therefore, it can be used in future breeding programmes to develop resistant varieties against M. vitrata. [ABSTRACT FROM AUTHOR]