Biology, host resistance, parasitoids and insecticidal management of the sugarcane mealybug Phenacoccus saccharifolii (Green) (Hemiptera: Pseudococcidae) in India

The sugarcane mealybug, Phenacoccus saccharifolii, has emerged as a major pest of sugarcane in India since the 2021–2022 season, but information on its biology, host-plant reaction, natural enemies and chemical control remains limited. Comprehensive laboratory and field investigations were conducted during 2023–2025 to address these knowledge gaps. The male and female mealybugs completed their life cycles in 21.9 ± 1.2 and 39.2 ± 1.6 days, respectively, and parthenogenetic amphitoky was observed in addition to sexual reproduction. Age-specific fecundity studies indicated a generation time of 31.5–32.5 days and a doubling time of 7–8 days. Screening of 230 sugarcane entries revealed considerable variation in their reaction to P. saccharifolii infestation, with the widely cultivated varieties Co 86032 and CoV 09356 showing the lowest and highest mean infestation levels of 3.22 and 71.85%, respectively. Four encyrtid parasitoids, Leptomastix sylvae, Aenasius hayati, A. arizonensis and Eotopus beneficus, were identified, with an overall parasitism of 15–19%. Leptomastix sylvae was the dominant parasitoid, accounting for 55.76–68.63% of total parasitism, and preferred third-instar mealybugs. Its male and female life cycles lasted 20.8 and 24.5 days, respectively. Two hyperparasitoids, Promuscidea unfasciativentris and Prochiloneurus pulchellus, also emerged from mummified mealybugs. Thiamethoxam was the most toxic insecticide against third-instar nymphs. The granular insecticides viz., thiamethoxam 0.9%+fipronil 0.2% GR, chlorantraniliprole 0.5%+thiamethoxam 01% GR and carbofuran 3% GR, provided more than 80% reduction in P. saccharifolii population following two applications at their respective recommended doses. These findings provide baseline information for developing integrated management strategies against P. saccharifolii.