Some warty patches slightly raised from the surface of the leaf sheath of some sugarcane plants in a sugarcane field at Sevanagala (6 0 36' N, 80 0 87' E), Sri Lanka, were observed during a field inspection in July 2016. These patches were irregular in shape and watery in appearance initially. Later, they become dry and reddish to dark red in colour. Microscopic examination on the damaged leaf sheaths showed large a population of minute mite. This study was conducted from July to September 2016 to identify this mite species and to investigate its damage symptoms and the occurrence in all sugarcanegrowing areas in Sri Lanka. Two hundred specimens of the mite were sent to Embrapa Recursos Geneticos e Biotenologia, Brazil, for identification. Fifty mite-infested plants from each age category, <5 months and >5 months, were inspected to study the damage symptoms and fifty randomly selected plants from each age group were inspected to record the damage incidence in the plantations in each sugarcane-growing site; Uda Walawe, Sevanagala, Pelwatte, Hingurana, Ethimale and Kantale. The specimens were identified as Sugarcane Blister Mite, Aceria sacchari Wang, 1964 (Acari: Trombidiformes: Eriophyidae). This is the first record of this mite on sugarcane in Sri Lanka. This mite has distributed in all sugarcane-growing areas in the country with different infestation levels. During the study period, the highest damage incidence on both age groups was recorded at Pelwatte while the lowest was at Hingurana.
Deltocephalus menoni is a sap-sucking insect causing severe losses to the cane sugar industry by feeding on the crop and acting as the vector of Sugarcane white leaf disease (WLD) in Sri Lanka. This study was conducted to determine the most preferred age of the sugarcane plant for optimum feeding of D. menoni. Sugarcane plants of the varieties SL 92 5588, SL 97 1442, SLC 2009 01, and SL 96 128 at six age categories from 1-6 months, were selected for the study. Female D. menoni adults fed on to measure the amount of feeding. Variation of the feeding of D. menoni on each variety with the plant age was estimated separately. The feeding of the D. menoni significantly varied with the age of the crop, and the highest feeding rate of 6.8 mm 2 , was recorded on four months old sugarcanes. The amount of secreted honeydew, measured as an indicator of the suitability of sugarcane for feeding of D. menoni, increased gradually from one month and reached the peak at four-month age. When the plant turned five-month-old, the amount of honeydew secretion reduced gradually, and the honeydew secretion significantly dropped at six months. A similar trend was observed in the amount of honeydew secreted by feeding on each variety, including the resistant check. The highest amount of feeding, 6.8, was recorded at four-month age, indicating four-month age of the sugarcane hybrids is the most vulnerable stage for D. menoni feeding, and the three to five-month period is the susceptible period for feeding.
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