Seasonal Population Dynamics of the Cowpea Aphid, Aphis craccivora (Koch) on Bean, and Its Correlation with Abiotic Factors under Kashmir Conditions
Malik Nowsheen *
Division of Entomology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir Shalimar, Srinagar – 190025, Jammu and Kashmir, India.
Shaheen Gul
Division of Entomology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir Shalimar, Srinagar – 190025, Jammu and Kashmir, India.
Akhtar Ali Khan
Division of Entomology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir Shalimar, Srinagar – 190025, Jammu and Kashmir, India.
Imran Khan
Division of Agricultural Statistics, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir Shalimar, Srinagar – 190025, Jammu and Kashmir, India.
Baseerat Afroza
Division of Vegetable Science, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir Shalimar, Srinagar – 190025, Jammu and Kashmir, India.
Faheema Mushtaq
Division of Vegetable Science, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir Shalimar, Srinagar – 190025, Jammu and Kashmir, India.
S. Suriya
Division of Entomology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir Shalimar, Srinagar – 190025, Jammu and Kashmir, India.
*Author to whom correspondence should be addressed.
Abstract
Aphis craccivora Koch, commonly known as the cowpea aphid, is a cosmopolitan and highly polyphagous pest of leguminous crops. It infests more than 50 host plant species across over 19 families easpecially from fabaceae. A two-year field investigation (2023–2024) was conducted in the Kashmir Valley to study the population dynamics of the cowpea aphid, Aphis craccivora Koch, infesting common bean (Phaseolus vulgaris L.) at three locations viz: Shalimar, Shuhama and Habak. The aphid population exhibited a characteristic sigmoidal growth pattern during both years. Initial colonization occurred in the 19th Standard Meteorological Week (SMW), followed by a gradual increase from the 20th SMW and a rapid rise by the 23rd SMW. Peak infestation was observed between the 25th and 30th SMWs, after which the population declined sharply by the 36th SMW. Mean aphid populations per three leaves were 44.79 and 46.11 at Shalimar, 47.71 and 43.30 at Shuhama, and 49.78 and 45.53 at Habak during 2023 and 2024 respectively. Highly significant positive correlation between maximum temperature and all aphid stages (nymphs, apterous, and alates), indicating that warmer conditions favored aphid multiplication and development. Minimum temperature also showed a positive but weaker correlation with aphid density. In contrast, both maximum and minimum relative humidity exhibited significant negative correlations, suggesting that humid conditions suppressed aphid buildup. These consistent trends across all sites indicate that temperature plays a promotive role, while relative humidity acts as a limiting factor in the population development of A. craccivora under Kashmir conditions.The study highlights the period between the 23rd and 25th SMWs as critical for implementing integrated pest management (IPM) strategies against A. craccivora in common bean.
Keywords: Aphis craccivora, common bean, population dynamics, temperature, relative humidity, correlation