Evaluation methods of sugarcane germplasm resistant to the leafhopper, Matsumuratettix hiroglyphicus (Matsumura) vector of sugarcane white leaf disease

Abstract

Sugarcane white leaf disease causes great damage to the sugarcane industry in Thailand. Leafhopper Matsumuratettix hiroglyphicus (Matsumura) is an important insect vector that transmits sugarcane white leaf phytoplasma. At present, there is no resistant varietie of sugarcane for white leaf disease. The purpose of this study was to develop the evaluating methods for screening resistant cane varieties against insect vector based on insect feeding activities, as measured by the puncture of the salivary sheath and the excretion of honeydew, and the effect on the growth and survival rate of insect vector when feeding on sugarcane. Based on the results of the study, we were able to classify sugarcane resistance tested from 7 sugarcane germplasms of 2 genara Erianthus and Saccharum in 3 groups as  1) Resistant cane from Genus Erianthus including germplasms ThE10-6, ThE99-146, ThE99-91, ThE03-7 and ThE03-5 were found a high average number of salivary sheath puncture marks between 20.50 ± 4.55 to 23.50 ± 3.53 marks with a low average amount of honeydew drop area between 0.13 ± 0.29 to 0.78 ± 0.96 square millimeters. In addition, the insect vector can not grow and transmit phytoplasma to sugarcane plants from this group. 2) Moderate resistance cane to insect vector from sugarcane genus Saccharum UT5 and 3) Non-resistance cane from sugarcane genus Saccharum KK3 which showed an average of low salivary sheath puncture marks at 13.35 ± 4.56 marks with an average amount of high honeydew drop area of 15.13 ± 5.91 square millimeters. Moreover, insect vector can grow until the full life cycle in the plants from this group. The development period from egg to adult is 62.69 ± 3.07 days and survival rates were 83.33 %. Therefore, using the method of feeding activities and growth of insect to evaluate sugarcane resistant