Survey of Pea Aphids, Acyrthosiphon pisum Harris (Homoptera: Aphididae) in Manipur Valley Conditions
Moirangthem Monalisa Devi *
Department of Entomology, College of Agriculture, Central Agricultural University, Imphal, Manipur, India.
K. I. Singh
Department of Entomology, College of Agriculture, Central Agricultural University, Imphal, Manipur, India.
Shravan M. Haldhar
ICAR-NCIPM, New Delhi, India.
Nilima Karam
Department of Entomology, College of Agriculture, Central Agricultural University, Imphal, Manipur, India.
Ksh. Sumita
Department of Entomology, College of Agriculture, Central Agricultural University, Imphal, Manipur, India.
Pukhram Bhumita
Department of Entomology, College of Agriculture, Central Agricultural University, Imphal, Manipur, India.
K. Mamocha Singh
Department of Entomology, College of Agriculture, Central Agricultural University, Imphal, Manipur, India.
Lokesh Kumar Mishra
Department of Entomology, College of Agriculture, Central Agricultural University, Imphal, Manipur, India.
Gajanand Chhimpa
Department of Entomology, College of Agriculture, Central Agricultural University, Imphal, Manipur, India.
R. Zorempuii
Department of Entomology, College of Agriculture, Central Agricultural University, Imphal, Manipur, India.
Ronibala Soibam
Department of Entomology, College of Agriculture, Central Agricultural University, Imphal, Manipur, India.
*Author to whom correspondence should be addressed.
Abstract
A roving survey was conducted during the rabi seasons of 2023–24 and 2024–25 to assess the distribution and incidence of the pea aphid, Acyrthosiphon pisum Harris, in five valley districts of Manipur: Bishnupur, Thoubal, Imphal East, Imphal West, and Kakching. Three blocks and three villages within each district were surveyed at the vegetative, flowering and podding, peak pod-formation, and maturity stages. Aphid abundance was recorded by counting individuals on 10 cm terminal shoots of ten randomly selected plants in farmers’ fields. The pest occurred in all surveyed blocks and villages during both seasons. Bishnupur consistently recorded the highest overall seasonal mean population, with 26.13 ± 4.88 aphids per 10 cm terminal shoot in 2023–24 and 26.60 ± 4.58 in 2024–25. Imphal East ranked second, recording 25.07 ± 3.03 and 24.98 ± 2.72 aphids per 10 cm terminal shoot in the respective seasons. Kakching recorded the lowest district-level means, while Thoubal also showed comparatively low infestation. Across districts, aphid populations increased from the vegetative stage, reached their maximum during peak pod formation, and declined at maturity. At the village level, Khoijuman Khunou in Bishnupur district recorded the highest populations, with 36.60 aphids per 10 cm terminal shoot in 2023–24 and 37.38 in 2024–25. These findings provide baseline evidence on the spatial and crop-stage patterns of pea aphid infestation in the Manipur valley and identify Bishnupur and the pod-formation stage as priorities for surveillance and timely management.
Keywords: Pea aphid, Acyrthosiphon pisum, roving survey, spatial distribution, seasonal incidence, pod formation, integrated pest management