1.3.2.3. Symptoms of common root rot (CRR)
Because of the difficulty to diagnose the disease as the above ground symptoms were not that obvious, this was remain unnoticed for long time. The major distinctive symptom of the common root rot is the dark brown discoloration of the sub crown internode portion of the root. This necrosis in extreme cases extends upwards …show more content…
Effect of Environmental conditions on the pathogens
1.5.1. Soil Moisture Disease severity and incidence depends upon many factors. Crown rot incidence is highly affected by soil moisture and nutrients. Higher soil moisture tends to have the greater crown root infection as compared to the direr soils. Also the high moisture conditions in the low lying areas help in the development of the fungus on the infected plants therefore promoting higher risk of crown rot in wheat. (Burgess et al. (1975), Klein et al. (1991)).
1.5.2. Temperature Temperature plays a crucial role in the survival of the fungus as well as in the spread of the disease. Poole et al., 2013 recently reported that there was a significant effect of the temperature on the distribution and the prevalence of the Fusarium species. From the survey conducted in the Pacific Northwest of the United States, F.pseudograminearum was more prevalent in the regions of lower elevations with lower moisture and higher temperature while F. culmorum was more prominent in the higher elevations with moderate to higher moisture and cooler …show more content…
Seed Treatment:
The pathogens which survive in the soil debris and serve as a source of primary inoculum for root diseases can be potentially managed by using fungicide as seed treatment to minimize root rot severity and thus increasing the yield. Though it is little expensive way of controlling these pathogens but they are economical if compared with the yield losses occurred due to root rots. Several reports indicated fungicide use as seed treatment can be one of the effective way to improve yield of crops specially wheat and barley. Along with the yield it also improves the test weight as well as 1000 kernel weight. Some of the reports showing the efficacy of the fungicide as a seed treatment are:
The fungicide Imazalil as a seed treatment, improved yield up to 6% and increased seed test weight in barley. Seed treatment also reduced the root rot severity index from 76 to 66 in barley (Hermann et al.,1990).
Stack and McMullen (1991) tested the effect systemic fungicides as seed treatment against the common root rot pathogen Bipolaris sorokiniana. The sub crown root internode index (SCI) of common root rot significantly reduced with seed treatment in barley and wheat. It also increased 7-9 percent yield.
1.6.3. Management of date of