Pulse Disease Concerns in Montana

1. Pulse Disease Concerns in Montana Dr. Mary Burrows Montana State University, Bozeman, MT mburrows@montana.edu 406-994-7766

2. Top 4 tips for a healthy pulse crop • Start with high-germ, good quality seed of an adapted variety • Ascochyta blight, bacterial blight, Anthracnose, and viruses can come in on seed 2. Use a fungicide seed treatment • Damping off, root rots 3. Good crop rotation practices • Root rots and foliar diseases 4. Scout crop on a regular basis - Foliar diseases and abiotic issues

3. Ascochyta blight • Three different species on Pea • Ascochytapisi, A. pinoides (Mycosphaerellapinoides), Phomamedicaginisvar.pinodella (formerly A. pinodella) • Different species on Lentils and Chickpeas • Lentil = Ascochytalentis • Chickpea = Ascochytarabiei • Spread by water splashing and wind • 60 – 75 F, humidity and rain

4. Montana Ascochyta seed testing • Action threshold = 0% chickpea, 0.7% pea, 2% lentil • Where ‘action’ means seed treatment for ascochyta or not planting that seed • Action threshold is based on relative resistance of the crop to the disease

5. Ascochyta blight symptoms: chickpea Leaf symptoms Pycnidia (fungal spore structures) Fungicide No fungicide Photo: Chengci Chen, Karnes Neill, MSU

6. Ascochyta blight symptoms: Pea, Lentil Photo: S. Markell, NDSU Photo: S. Markell, NDSU

7. Bacterial blight of Pea • Psedomonas syringae pv. pisi • Seedborne inoculum (persists 3 years) • Also residue- and soil-borne • Local splash dispersal is the most important for spread • Yield loss strongly correlated with leaf area loss • No adapted cultivars with resistance

8. Bacterial blight of pea Angular lesions Watersoaking and ooze Hail damage

9. Use a fungicide seed treatment • Help manage root rots • For a few weeks • Aid emergence and stand establishment • Why is this important? • Disease likely occurs early, shows up later • Protect against seed-borne diseases • Use Mertect/LSP against Ascochyta in chickpea; Dynasty (azoxystrobin) good for pea, lentil Ascochyta Photo: S. Markell, NDSU

10. Seed treatment trials • Uniform pea seed treatment trials (ND, MT, WA) • 6 locations, 2008; 2 locations, 2010 • Low disease severity in general • Agronomics were dependent on site and year • In Montana: • Cruiser increased yield if there was pea weevil pressure • No one seed treatment stood out as better than the rest • Chickpea seed treatments, 2007 • Very wet site at Sidney, mefanoxam (metalaxyl) increased stands and yield in kabuli chickpeas - Pythium

11. Seed Treatment • Will seed treatments always pay? NO • Questions to ask: • How long have you been planting pulse crops? • What’s you’re rotation? • Do you have stand establishment problems? • Have you seen problems in your fields?

12. Seed Treatments • Make sure your product has Fusarium and Rhizoc control (True Fungi) in addition to Pythium (metalaxyl/mefanoxam) • Examples: ApronMaxx, Trilex AL, Acquire + Acronis • 2009 ND field crop fungicide guide • Product labels • Use Mertect/LSP if you have Ascochyta in the seed; Dynasty will also work but only for pea and lentil (chickpea Ascochyta is resistant to strobilurins)

13. Good crop rotation practices • 3-4 year rotation between legume crops is recommended for disease management • Should reduce root pathogen population: particularly the Fusarium species that attack pea • Will also reduce inoculum for foliar pathogens

14. Fusarium Rhizoctonia • Can be stress related • Common in drought years • Dry rot with indistinct brown lesions-occasional general browning • Few secondary roots • Warm moist soil • Distinct chocolate brown to dark red lesions • Often seen in association with Fusarium

15. Lentil with root rot Healthy lentil Photo: S. Mills, MSU

16. Fusarium wilt of pea Fusarium oxysporum f.sp. pisi • Resistant varieties • Seed treatment • Rotation

17. Scout crop on a regular basis • Foliar diseases • Ascochyta blight • Powdery mildew • Abiotic issues

18. Foliar Fungicides • Serious disease = serious yield reductions • Fungicides can help prevent loss • Fungicides will not always pay: beware the development of fungicide resistance! • Scout for diseases • Consider climate • Humid with rain in the forecast • Early bloom is optimum time to spray • Late-season fungicides will not penetrate thick powdery mildew (peas) – neither will dessicants

19. Fungicide Resistance in Chickpeas • Fungicides Available before 2005 • Chlorothalonil – Protectant (Bravo) • 2002: Azoxystrobin – QoI class (Quadris) • 2003: Pyraclostrobin – QoI class (Headline) • Initially, QoI’s very effective, so effective that… • Growers were spraying multiple applications • Resistance to Headline/Quadris identified in 2005 • Widespread resistance in 2006

20. Ascochyta resistance to Headline/Quadris (strobilurins) Percent of Isolates From K. Wise

21. 2007 Chickpea Fungicide Trial- Minot Yield lb/A From K. McKay

22. Ascochyta Blight in Chickpeas • Ascochyta in chickpeas does not cause disease in lentils or peas • Ascochyta population in chickpeas is resistant to strobilurin fungicides • Headline and Quadris ineffective • Still the case • Rotate chemicals • Bravo, Proline, Endura, Proline

23. Preventing/Managing Fungicide Resistance • Rotate FRAC groups! Not product • Follow the label • Use appropriate timing • Don’t wait until epidemic is full force • Use appropriate rate • Use appropriate technique (nozzles, water, etc.) • Tank mixes

24. Thank you • Sam Markell, Rubella Goswami, NDSU • Chengci Chen, Karnes Neill, Joyce Eckoff, Rachel Leisso, Ken Baker, MSU • Northern Pulse Growers Association • USDA-Cool Season Food Legume Program

25. Moccasin, MT, 2008

26. Sidney, MT, 2008

27. Moccassin, 2010

28. What is causing our root rots? • Over 80% isolates from ND Survey were Fusarium species • In MT, small chickpea survey in 2007: Fusarium, Pythium causing damping off of seed • Rhizoctonia can also be important • Do all the Fusarium species cause disease, equally?

30. Distribution of fungal isolates in field peas in 2008