There has been a shift in the last few years towards round up ready and low lignin alfalfa. Traited alfalfa is becoming a key factor in growing high quality, high yielding alfalfa. Leta Larsen, Forage Specialist with CROPLAN discusses not only how these traits impact yield and quality but also how the underlying genetics that can play a big role in disease prevention and stand persistence.
First, let's talk alfalfa traits. There are 2 traits offered through Croplan Alfalfa, first is Round Up Ready and the second is HarvXtra. The HarvXtra is always stacked with the Round Up Ready trait in the CROPLAN varieties.
“HarvXtra is a trait, not a variety,” started Leta. “[HarvXtra] is a trait that allows for lower lignin alfalfa. Since it has lower lignin, it is going to start at higher quality… So if you were to harvest every 28 days you would see around 20% higher quality- particularly better digestibility, higher NDFD and higher RFQ.”
In addition to choosing the best trait package to increase your alfalfa quality, the genetics you choose can give you protection from diseases. AA Alfalfa Genetics gives you protection from Aphanomyces and Anthracnose.
and and Anthactnose stem and crown disease later on in the alfalfa plants life.
Aphanomyces is a severe root rot disease that you can see in seedlings and mature stands. Typically, you’ll see Aphanomyces in May and June but you could also see an impact on mature stands in wet fall conditions. Aphanomyces stunts growth. It could appear with symptoms representative of nutrient deficiencies or it might look like herbicide carry over. The growth is stunted and roots will appear gray and water soaked. Eventually the roots turn brown, collapse and die. The roots that do survive, will never have the vigor and potential of a plant that was not infected.
“With the AA genetics we have high resistance + to Aphanomyces- all races,” shared Leta. “This is the gold standard for disease resistance in alfalfa.”
Anthractnose typically infects in mature alfalfa stands and can show up as a foliar disease as well as severe crown rot. Wet conditions in the late summer causes diamond shaped lesions that can escalate to a girdle causing Shepards Hook. This results in leaf and stem loss that can equate to a yield loss of 25-30%. AA genetics include resistance against all races of Anthractnose, including race 5. This disease resistance rating is only provided through genetics coming from Forage Genetics International (FGI).
There are a few other diseases that alfalfa growers should have on their radar. The first is Phytothera root rot which AA genetics provide excellent resistance. Phytothera was one of the first diseases identified in alfalfa so across the market there is fairly good control today. The second is Pithium that causes seed rot in the soil or dampening off where if it does germinate but later dies. A fungicide seed coating with Apron XL can help provide control for Pithium with it’s Grozone 34% coating.
When protecting yourself against these diseases, the best course of action is variety selection.
Aphanomyces, Pithium and Phytothera are hard to control with crop rotation because they can last in the soil 10-30 years even without the presence of a host crop. By choosing a host with resistance you eliminate that portion of the disease triangle, giving your crop its best chance for successful stand persistence.
To learn more about these diseases, and the available traits and genetics available today in our alfalfa line up, tune into the full podcast episode with Leta. In our next episode we will be focusing on alfalfa management in season, and how precision ag affects agronomics of alfalfa.