Population Dynamics of the Rose aphid Macrosiphum rosae (Hemiptera: Aphididae) and Its Management under Protected Conditions in Kashmir

Abstract

Aims: To correlate the aphid population with the weather parameters, i.e., temperature (minimum and maximum), minimum relative humidity, maximum relative humidity. Bio-efficacy of different molecules against aphid population. Study Design: RCBD (Randomized Complete Block Design) was used for the experiment. A polyhouse that was separated into three equal-sized blocks (14.6 m × 1.52 m) was used to plant a variety of roses. Eleven subplots, each measuring 1.11 meters by 1.52 meters, were created from each block. Five plants were cultivated at the specified spacing of 35 cm by 25 cm in each plot. Location and Study Period: The current study was conducted under protected conditions in the Division of Floriculture & Landscaping Architecture's experimental block at SKUAST-K's Shalimar campus in Srinagar from March 2022 to December 2022. Methodology: Under polyhouse conditions, ten randomly chosen rose plants were used to record the seasonal occurrence of rose aphids. The observations were made with a 10X hand lens. RCBD design were used to assess bio-efficacy of different molecules. Two spray rounds were sprayed in the polyhouse at 14-day intervals after the aphid population on roses was counted the day before the spray. Following both treatments, observations were made of two randomly chosen plants from each treatment at 1, 3, 7, and 15 DAS (days after spraying) (3 leaves and one flower bud from each plant). A statistical analysis was conducted on the recorded data. Results: Aphid population build-up began in the second week of April (14th SMW) and peaked in June and July (26th and 27th SMW), but the initial incidence of aphid population began in March (12th SMW). Aphid populations have been found to positively correlate with both minimum and maximum temperatures. Aphid population and relative humidity (minimum and maximum) were shown to be negatively correlated. The study revealed a significant positive correlation between aphid population density and both minimum and maximum temperatures (r = 0.546–0.586, p < 0.01), whereas relative humidity exhibited a significant negative association. Among the evaluated treatments, Thiamethoxam 25% WDG at a rate of 0.3 g/L achieved the highest level of aphid population suppression (>90%) under protected cultivation conditions. Conclusion: The initial incidence of aphid population started from March- 12th SMW and reaching the peak in June- July (26nd and 27th SMW). A positive correlation was reported between aphid population and minimum & maximum temperature and negative correlation was observed between aphid population and relative humidity. Treatment Thiamethoxam 25% WDG @0.3 g/L was found as the most effective treatment for suppressing the aphid populations.