Fungal plant pathogens observed on perennial cereal crops in New York during 2017-2018

Authors: Fulcher, Michael; LAW, EUGENE - Cornell University; WAYMAN, S - Cornell University; RYAN, MATTHEW - Cornell University; BERGSTROM, GARY - Cornell University

Submitted to: Renewable Agriculture and Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2021
Publication Date: 3/7/2022
Citation: Fulcher, M.R., Law, E.P., Wayman, S., Ryan, M.R., Bergstrom, G.C. 2022. Fungal plant pathogens observed on perennial cereal crops in New York during 2017-2018. Renewable Agriculture and Food Systems. 37:279-291. https://doi.org/10.1017/S1742170521000582.
DOI: https://doi.org/10.1017/S1742170521000582

Interpretive Summary: Perennial grain crops are an alternative to traditional annual crops, like wheat and barley. Perennial grains can be grown in one location for 3-5 years, require fewer resources than annual crops, and may contribute to sustainable agriculture. However, plant diseases that are a problem in traditional annual crops may pose similar challenges to the growth of perennial crops. This preliminary study recorded plant diseases found on two perennial crops grown in New York from 2017-2018. Most diseases found on perennial crops were the same as those found in related annual crops. The tools used to control these plant diseases in annual crops cannot be used in perennial crops, and because of this, alternative approaches to disease control are needed. In one experiment, planting a perennial crop mixed with red clover reduced the amount of a plant pathogen that survived from one year to the next. This practice of growing two plants together is called intercropping and could be useful in perennial crop production. This information benefits farmers deciding how to incorporate perennial crops into their existing practices and scientists working to improve perennial cropping systems.

Technical Abstract: Perennial grain crops are emerging as a promising addition to sustainable agricultural systems because of their low-input requirements and delivery of ecosystem services. However, adoption of these crops is expected to bring novel management challenges, including those related to plant disease. In New York, fungal pathogens of annual grains have a significant impact on crop yield and value and are generally controlled through a combination of host resistances, cultural practices, and chemical fungicides. Without the availability of crop rotation and soil tillage practices, disease control in perennial grain systems may be problematic, and little is known about perennial grain crop susceptibility to local plant pathogen populations. During 2017 and 2018, ongoing field trials of two perennial grain crops recently introduced in New York, intermediate wheatgrass (IWG; Thinopyrum intermedium) and perennial cereal rye (PCR; Secale cereale), were assessed for the presence of putative fungal pathogens on actively growing plants, overwintered crop residue, and harvested grain. A total of nine potential host-pathogen combinations were recorded based on symptomology, pathogen morphology, and DNA sequences. Common annual crop pathogens were recovered most frequently, but, at one site, Phyllachora graminis, causal fungus of tar spot and a pathogen not previously reported on crops in New York, was found on IWG. Residue colonization by an important toxigenic pathogen (Fusarium graminearum) was high in both crops, though mycotoxin levels in associated grain were low, indicating either the hosts or environment were unsuitable for disease development. Seed-borne fungal communities differed across crops and locations, and black point, a condition caused by Alternaria and Bipolaris fungi and indicative of compromised grain quality, was prevalent in PCR under some conditions. Growing PCR with intercropped red clover (Trifolium pratense L.) resulted in less Stagonospora colonization of stem residue, and PCR grown with an oat (Avena sativa L.) nurse crop had a reduced incidence of black point. These alternative cultural practices may prove useful for managing disease in perennial grains. Our results suggest the incorporation of perennial crops into the agricultural landscape will lead to familiar plant disease problems requiring new solutions as well as new problems that may require significant research investments.