Seasonal Variation in Uzi Fly Infestation on Muga Silkworm (Antheraea assamensis Helfer) in Jorhat District of Assam, India

The muga silkworm (Antheraea assamensis Helfer) is reared outdoors and is vulnerable to uzi fly infestation, which may vary among crop seasons. This study examined seasonal infestation at Government Sericulture Farm, Titabar, and Na Chalauria Gaon in Jorhat district, Assam, in relation to weather conditions. Observations were conducted from May 2022 to June 2023 across six crop seasons: Aherua, Bhodia, Katia, Jarua, Chotua and Jethua. Mature larvae were examined for externally visible uzi fly eggs or penetration scars, and infestation percentages were compared with maximum and minimum temperatures, morning and evening relative humidity, rainfall and bright sunshine hours using Pearson's correlation coefficient. Infestation was recorded in all six crops at both locations. The highest infestation occurred in Chotua (36.67% at Titabar and 42.67% at Na Chalauria Gaon), followed by Jarua (32.67% and 34.67%, respectively). The lowest recorded values were 13.33% in Bhodia at Titabar and 12.67% in Jethua at Na Chalauria Gaon. At both sites, infestation was negatively correlated with maximum and minimum temperatures, evening relative humidity and rainfall, moderately positively correlated with morning relative humidity, and negligibly correlated with bright sunshine hours. Only the association with maximum temperature at Titabar reached the 5% significance threshold (r = −0.82; p = 0.047). These findings indicate seasonal variation in infestation at the sampled locations and suggest that monitoring may be particularly useful during Chotua and Jarua. Further observations across additional years are required to assess the consistency of these patterns.