Molecular Insights and Seasonal Dynamics of the Pink Mealybug, Maconellicoccus hirsutus on custard apple (Annona squamosa L.)

Abstract

The pink mealybug, Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae), is a highly polyphagous pest that induces leaf curling, fruit malformation, honeydew deposition and significant yield losses in custard apple (Annona squamosa L.). Accurate identification of M. hirsutus is often difficult because of its pronounced morphological variability, thereby necessitating molecular approaches as a more reliable alternative. In this study, molecular characterization of M. hirsutus population infesting custard apple was conducted. High-quality genomic DNA was extracted and the mitochondrial cytochrome oxidase I (COI) gene was sequenced. BLAST analysis revealed 100% similarity with sequences available in GenBank and phylogenetic analysis clustered the Vijayapura isolate with other Indian populations, indicating limited genetic divergence. Population monitoring indicated peak densities of 71.28 individuals per fruit during the 47ᵗʰ Standard Meteorological Week (SMW) of 2023 (fourth week of November) and 68.32 individuals per fruit during the 43ᵗʰ SMW of 2024 (fourth week of October). Regression analyses indicated that meteorological factors explained 58–61 per cent of pest severity, underscoring the influence of weather in conjunction with other biotic and management factors. These findings provide baseline information on the molecular identity and seasonal dynamics of M. hirsutus, supporting predictive pest management and the development of ecologically based integrated pest management (IPM) strategies in custard apple orchards.