Field Diagnosis, Damage, and Seasonal Dynamics of Nygminae Tussock Moth, Orvasca subnotata on Tuberose in India

Abstract

Tuberose (Agave amica), a commercial flower crop in India, has recently been observed to suffer severe infestations by the nygminae tussock moth, Orvasca subnotata Walker (Lepidoptera: Erebidae). The larvae cause substantial economic losses by feeding on floral buds and petals, leading to marketable losses, particularly during the festive season when tuberose prices are at their peak. This study provides the first report of O. subnotata infestation on tuberose and aims to assess its seasonal occurrence and damage potential. Morphological examination and molecular identification using cytochrome c oxidase subunit I (COI) gene sequencing confirmed the pest's identity. Seasonal incidence studies conducted in 2023 and 2024 revealed that O. subnotata occurs in tuberose fields during the rainy season (May to October), with infestation levels peaking in September (21.33% to 28.33% bud damage). O. subnotata damage was also assessed on ten widely cultivated tuberose varieties during its peak activity period (August–September); however, no significant varietal preference was recorded. Correlation analysis revealed that infestation levels were significantly and positively associated with minimum temperature, evening relative humidity, rainfall, and number of rainy days, while negative correlations were observed with maximum temperature, sunshine duration, and evaporation rate. These results suggest that warm, humid, and overcast conditions favor pest outbreaks, providing critical insights for forecasting and developing weather-based pest management strategies. Given its economic impact on tuberose cultivation, further research is needed to develop effective management strategies. This study highlights the importance of targeted pest control interventions to mitigate losses and sustain tuberose production in India.