Sustainable Management of Coccidohystrix insolita (Green) (Hemiptera: Pseudococcidae): An Emerging Threat to China Rose; Hibiscus rosa sinensis L. Using Essential Oil

Abstract

The present study reports the heavy infestation of Coccidohystrix insolita (Green) on China rose; Hibiscus rosa sinensis. Critical observation revealed that infestation starts with the appearance of first instar nymphs on the tender portion of the plants. Later they spread to shoots, leaves, buds and flowers of the plant. Leaves and buds of highly infested plants become yellowish, gradually dry and later fall down. Correlation co-efficient between mealybug population and weather parameters revealed that the maximum (r = 0.429) and minimum (r = 0.445) temperature were significantly positively correlated whereas morning relative humidity (r =  − 0.501) was significantly negatively correlated. Regression analysis showed that morning relative humidity significantly imparted 25.10% variation to their population build up. Two ant species namely Camponotus compressus and Solenopsis geminata were found associated with the mealybug. It was observed that two predators belonging Coccinellidae and Lycaenidae families were feeding on the immature stages of the mealybug. Four oils namely camphor, eucalyptus, lemongrass and neem oil were tested against the mealybug to determine their insecticidal activity. The resultant biological parameters for eucalyptus, lemongrass and camphor oils were LC₅₀ values of 2.45, 5.10 and 7.81 mg/L air respectively for fumigant toxicity. This study reports for the first time the insecticidal potential of eucalyptus, camphor and lemongrass essential oils against them.