By Yeshi Wamishe, Extension Rice Pathologist
Knowing rice cultivar responses to diseases ahead of planting along with knowing your field history is advantageous when it comes to managing rice diseases. It is important to match your field history with the variety of your choice. For instance, planting blast susceptible varieties in historically blast prone fields is not a good start. If this is done, additional planning may be needed for fungicide application. Fungicide application does not profit in fields that are not well managed. Best cultural methods are always encouraged in any field planted with either a disease susceptible or resistant rice. Planting kernel or false smut susceptible rice in fields with a history and applying excessive nitrogen fertilizer result in severe damage under favorable weather conditions.
Weather conditions are hard to predict. However, we know favorable weather conditions for crops are also conducive for disease development. When varieties are matched in the right fields and planted following the recommended planting time, seeding rates, receive adequate nitrogen fertilizer and are well managed with water and other nutrients, success can easily be predicted. In such fields diseases remain low or absent.
The rice cultivar reactions table below presents reactions determined based on historical and recent observations from test plots and in grower fields across Arkansas and other rice states in the southern USA. In general, these ratings represent expected cultivar reactions to diseases under conditions that most favor severe disease development.
Reactions are described as: R = Resistant; MR = Moderately Resistant; MS = Moderately Susceptible; S = Susceptible; VS = Very Susceptible. Cells with no values indicate unavailability of definitive Arkansas disease rating information at this time. Disease ratings from the past may have been modified based on series of observations. Lodging may be caused by diseases such as sheath blight; therefore lodging data are included in the table for your additional information.
Also available in pdf here: 2017 Cultivar Disease Reaction Table