Rice Disease Calendar

One of the biggest questions I receive each year has to do with whether or not a specific disease is present on rice at a specific growth stage.  Most, and I say most since this is a statement that can differ from year-to-year or location-to-location, rice diseases, much like the diseases observed in our other crops, occur at particular times of the year or at a specific growth stage.  For example, bacterial panicle blight is observed prior to harvest while blast can be observed at several different growth stages throughout the season.  More often than not the presence of a specific disease will depend on planting date, especially since over the past few years leaf blast has been observed earlier in the season than in years past.  In other cases, and regardless of planting date, the environment exerts the greatest impact as to whether or not a particular disease occurs.  For example, bacterial panicle blight generally occurs when high temperatures occur at the time of flowering.

The second most important factor as related to disease has to do with the previous crop.  Fields with no history of rice will not be as likely to have diseases that occur as a result of inoculum present in the field (e.g., leaf blast, false smut, kernel smut).  In fact, most of the diseases on the attached disease calendar are caused by inoculum present as a result of residue remaining in the field from previous seasons.  The only real exceptions are the seedling diseases and sheath blight because the organisms that cause these specific diseases are considered to be ubiquitous and occur almost everywhere the plants are grown.  However, the specific anastomosis group that causes sheath blight may not be present in every field.

By no means is the attached calendar an exhaustive list of ALL of the rice diseases encountered throughout our production system.  The diseases included should be considered to be some of the more common and recognizable diseases regardless of location within MS.

The arrows to the right of the diseases indicate the likely period of infection that is generally required for symptoms to be expressed as well as the period whereby the disease could continue to be an issue.  However, the presence of seedling diseases will ultimately depend on the seeding date and environment that occurs subsequent to rice seeding.

Rice disease calendar (Rice Disease Calendar)