PACHYMETRA ROOT ROT SURVEY IN THE HERBERT RIVER DISTRICT 2014-2015

PACHYMETRA ROOT ROT is a very significant root disease in the Australian sugarcane industry and is widely distributed through most districts. The disease leads to a poor and inadequate root system and rotted primary roots are the most obvious symptoms. Only limited surveys have been conducted for the disease in the Herbert River district. In 2014–15, over 200 hundred crops were sampled and assayed for Pachymetra root rot severity. Details related to variety, soil type, sub-district and crop cycle for each sample were sourced. A significant proportion of crops would be expected to suffer yield losses from Pachymetra root rot (estimated at over 35%), based on the spore counts. The worst affected sub-districts were Lannercost, Foresthome, Cordelia and Leach. Of the four varieties surveyed, spore counts were highest under the more-susceptible Q237A. The disease was prevalent across a range of soil types, but the highest spore counts were in clay and silty loam soils. The disease is leading to significant yield losses, warranting improved management practices that will maximise productivity.