2018 Disease Management Begins Now!

Winter wheat harvest is complete across the province and yields have been good to above average in the majority of areas, with good quality and very little Fusarium/DON reported. Stripe rust, especially in Essex/Chatham-Kent, did not have a big impact this year in those fields planted with a susceptible variety due to lower inoculum (spores) coming in from the US, increased scouting and well timed foliar fungicide applications. Remember to consider disease ratings for Fusarium head blight, leaf and stripe rust, etc. when making your wheat variety choices this fall. Ask your seed dealer or check the Ontario winter wheat performance trial report for more information on specific varieties.

Growers frequently ask, "if I had stripe rust this year does that mean I will have stripe rust again next year?" The easy answer is NO since wheat rust diseases need living green plants to survive and as long as we have winter we start clean each year. The mild winters the past two years have resulted in a larger geographical area in the southern US where stripe rust can overwinter as well as more spores than normal coming into Ontario, and arriving earlier than normal. The cereal rust network, which OMAFRA is a part of, will continue to monitor the overwintering status of leaf and stripe rust this winter and spring.

Regardless of whether conditions have been wet or dry, the soybean crop can face disease issues. The weather in some regions has favoured soybean cyst nematode (SCN), and sudden death syndrome (SDS), and in others has favoured white mould. White mould is easy to identify but SCN and SDS can be misdiagnosed for other common problems. For SCN, dig plants with a shovel and gently remove soil and examine roots for the presence of the small white to yellow cysts. If you see no or very few cysts on the roots this is a good indication you have a low population or a highly resistant variety. If you have 50 or more cysts, you are looking at a less tolerant variety or your SCN population is changing to SCN types that can reproduce on the PI88788 SCN resistance source. In many areas of the US Midwest such as Iowa, Illinois, Missouri and other states, SCN populations which can reproduce on the PI88788 SCN source are very common (50% of tested fields or more). In Ontario, these SCN populations do occur but to a lesser extent. They have been found in 25% or more of the fields tested by Dr. Tom Welacky at AAFC in Harrow.

So how do we keep SCN populations down or delay population shifts? SCN management includes rotation with non-host crops such as wheat and corn, rotating resistant varieties as well as rotating between PI88788 and Peking SCN resistance genes. Consider SCN seed treatments, scout for cysts, and take an SCN soil test to monitor nematode populations. When it comes to SCN, remember that regardless of the conditions, SCN will steal yield every year. If anything, SCN is consistent and that is why it is called the "silent yield robber".

For sudden death syndrome (SDS), symptoms on the leaves appear as yellow and brown areas between the veins while the veins remain green, which can be confused with manganese deficiency. Leaves will drop but the petioles (leaf stalks) will remain on those plants infected with SDS. To confirm SDS, cut open the root and stems and look for rotting roots and brown discoloured streaks in the stem. With SDS the center pith will remain white.

As we are approaching the end of the 2017 growing season, it is the perfect time to reflect on the season and note areas in your fields which were problematic and did not perform as well as expected. They may have had visual symptoms or had reduced yields which stick out on the yield monitor. Take what you learned and observed this year and include this information into your plans for next year. Plan to conduct pre-harvest scouting or post-harvest sampling of your fields. What you observe now in terms of diseases, insects, weeds, and other problems will assist you in selecting the appropriate varieties and management strategies not only next year but for future years as well.

Start by taking a soil sample for soil issues such as pH, fertility, etc. and make plans to correct those issues in 2018. If you plan to plant soybeans in these fields next year, the soil sample could be split into two to allow for SCN testing. An SCN test should be taken every 4 to 6 years to determine changes in SCN population. Remember, DO NOT grow the same SCN variety year after year in a field as this could cause a shift in the SCN population, making that variety's resistance package ineffective and resulting in increased SCN population levels in a field.

Selecting the right genetics for 2018 is critical to high yields and it is important to remember to include disease tolerance or resistance characteristics of your hybrid/variety in the decision process. Diseases such as corn ear moulds, Northern corn leaf blight, soybean cyst nematode, Fusarium head blight, rusts in wheat and oats, Phytophthora root rot, sudden death syndrome and many others pose a risk across the province each year. Remember, each field is different and start by selecting hybrids/varieties with resistance or tolerance appropriate for each field based on disease risk potential (high levels of crop residues, short rotations such as corn/corn, soy/soy) and especially those with a history of disease. Remember the best defense is a good offense!

Reduce your disease risk next year and make selecting the appropriate hybrids/varieties for those diseases part of your must-have list! Check the Ontario Performance Trials for corn, soybean, and cereals and talk to your local seed dealer for more information pertaining to specific hybrids/varieties. Do not take this important decision lightly!

Ontario variety performance trial websites:

For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca