All News

Importance of Crop Disease Surveys

Together with Manitoba Agriculture and Resource Development, Manitoba Crop Alliance performs annual disease surveys for our major crops. It can sometimes be a question of whether information gathered is of significant value, especially in years where disease incidence is quite low. To that point, sometimes in those years we get the most interesting data and learn a great deal from our findings.

Generally, the premise of a crop disease survey is to determine the following:

  1. Disease prevalence: percent of fields infected
  2. Disease incidence: percent of plants infected
  3. Disease severity: based on a rating scale for each disease being sampled
  4. Disease distribution: distribution pattern in a field, municipality, province – is there a pattern?

When a surveyor visits a field, they record notes on the four points above and compile that information into a large data set for the entire survey. Once compiled and analyzed, the data set gives us more insight into each disease.

First, we can identify that year’s greatest disease threats, what crop(s) it affected and at what level of severity. This enables us to assess the current risk of each disease and moving into the next growing season, what could be the greatest risk for producers. To that effect, it is a great starting point for future disease risk maps, which are a helpful tool to the whole industry. A risk map shows which diseases (or other pests) are likely to be the greatest risk in a given area, usually for the next growing season. This considers the points above (prevalence, incidence, severity and distribution), seasonal forecasts, seed treatment options, fungicide use, crop rotations and more.

When performing a disease survey, the surveyor is in contact with each grower for permission to scout fields. As an obvious courtesy, the producer is informed of what diseases were found and in what severity. Field results will help each producer evaluate the efficacy of their fungicide program and determine what are the best products for their operation. The producer will take those field results and track the crop impact from the disease. This gives them really great information on the progression of the disease following the survey. For instance, how precipitation (or lack thereof) and growing season length encouraged or discouraged disease growth. Was crop standability impacted? Was crop maturity affected? Did any nutrient deficiencies impact disease pattern?

There are so many things that we can learn, just by knowing the presence of a disease in one field. The MCA recommends producers get involved with surveys like this whenever the opportunity arises. It is a great tool for the whole industry and at the very least, will build a good relationship between the surveyor and producer, which is a true asset to both individuals.