| Abstrakt: |
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 mm2, 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. [ABSTRACT FROM AUTHOR] |
