Dorge, S.K., Dalaya, V.P., & Pradhan, A.G. 1972 Studies on two predatory Coccinellid beetles, Pharoscymnus horni Weise and Chilocorus nigritus Fab., feeding on sugar-cane scales Aspidiotus glomeratus G.. Labdev Journal of Science and Technology 10(3-4): 138-141.

Notes: Melanaspis (Aspidiotus) glomeratas (Green), which had previously been considered as a minor pest, has of recent years caused considerable damage to sugar-cane in the Indian State of Maharashtra, reducing the yield by 5-10 tons/acre and also reducing the sucrose content of the cane. Information is given on the morphology and bionomics of two Coccinellids, Pharoscymnus horni (Weise) and Chilocorus nigritus (F.), which were found preying on it in the field and were studied in the laboratory with a view to mass-rearing and release for biological control. In the laboratory, P. horni completed a generation in 37-42 days. The eggs were laid singly or in small batches in the leaf sheaths, in debris or under the scales, and females laid 17-21 eggs each in 6-10 days. The egg, larval, prepupal and pupal stages lasted 4-7, 13-23, 1-2 and 5-8 days, respectively, and the adult males and females lived for 20.6 and 25.1 days. C. nigritus completed a generation in 26-28 days. The eggs were laid singly or in small groups in similar places to those of P. horni, and the females laid 12-34 eggs each in 7-18 days. The egg and larval stages lasted 3-6 and 13-16 days, respectively, and the adult males and females lived for 12 and 15 days. Both Coccinellids are recorded as preying on many other species of scale insects and mealybugs, which are enumerated, but during the observations in Maharashtra P. horni was found attacking only M. glomerata and C. nigritus only M. glomerata, Parasaissetia (Saissetia) nigra (Nietn.) and Saccharicoccus (Trionymus) sacchari (Ckll.).