Melanaspis glomerata (Green)

Melanaspis glomerata has become a very serious pest of sugarcane where ratoon crop is taken up. The grayish black scale insect infests 5-6 months old crop. Due to continuous desapping canes start shriveling up resulting in stunted growth. In severe infestations in susceptible cultivars, yellowing of leaves and even drying up of canes is observed.

Melanospis glomerata is ovoviviparous in reproduction. Six to eight month old healthy canes without any fissures and with undamaged buds of susceptible varieties like Co671, Co4133 and Co740 are selected for culturing the scale insect. The cane pieces are cut into 40-45 cm pieces bearing three internodes each. The sets are surface sterilized with formalin and 2% Benlate, shade dried and the cut ends dipped in moulten paraffin wax to prevent fungal infection and drying. The sets are arranged in plastic trays (30 x 40 x 6.5 cm) the inner sides of which are painted black or in breeding cages 0.3 sq metre. The initial culture of the host insect is started by bringing cane scrapings bearing full grown scales from heavily infested fields. The scrapings are placed over a piece of mosquito net helping them spread over prepared cane pieces placed horizontally. The trays are covered with a black cloth and fastened with a string. Similarly the cages are covered with black cloth to obtain better setting and good culture by creating dark conditions. After 48 hrs, the sets are rotated to ensure uniform infestation. Once pure culture is established, the subsequent infestation is obtained by placing the freshly prepared canes in close contact with well infested canes. After 72 hrs they are planted by removing the wax from one side in sterilized moist sand in cages or in cement pots 62x62x30 cm containing jungle soil. The planted sets are covered with polyvinyl cages 20 cm in height and 15 cm in diameter and covered with lid on which window is cut and fixed with net to provide aeration.

The inoculated cane sets are placed in specially designed iron frames (45x35x20 cm) containing 5x5 cm squares and sterilized water. The water in the tray is changed once in two days.