Mohammad, A.M., El-Khouly, A.S., El-Metwally, E.F., & Shalaby, M.S. 2005 Factors affecting distribution patterns of the soft scale, Pulvinaria tenuivalvata (Newstead) in sugar cane fields.. Egyptian Journal of Agricultural Research 83(1): 95-107.

Notes: Population estimation of P. tenuivalvata was done in different sites of the cane field, i.e. east, north, south, west and field centre, in Giza, Egypt. Insect density proportionally increased from May to December in all field sites and the scales became intensive throughout September-November. The plants located in the west site intensively harboured the highest population of scales followed by the north site. The number of scales on the plant - east and south sites were approximately similar. Centre site had the lowest number of insects. Plant infestation decreased as the distance between plant location and field border increased, so cane plants nearby the field border were heavily infested than plants far from the field border. At the same time, the lower part of the cane plant seems to be the poorest site for insect location and feeding while the middle was the most favourable site followed by the upper part of the cane plant. P. tenuivalvata preferred the lower surface of cane leaves for settling and feeding. Nymph and adult stages showed clear preference to north-western direction of sugarcane field where its population was always abundant throughout the season.