Color Me Pink, Seed Treatments in Wheat. Dr. Madeleine Smith Best of the Best 2015

Transcription

1 Color Me Pink, Seed Treatments in Wheat Dr. Madeleine Smith Best of the Best 2015

2 Root Rots A Complex of Diseases Common Root Rot (CRR) Bipolaris sorokiniana Crown Rot (FCR) Fusarium spp. Take-all Gaeumannomyces graminis var. tritici Other root diseases Sharp Eyespot Rhizoctonia ceralis Snow Rot Pythium spp. Snow Mold Fusarium nivale & Typhula spp. Strawbreaker foot rot Tapezia yallundae

3 Common Root Rot - CRR Common Root Rot Bipolaris sorokiniana Symptoms brown lesions on roots & SCI dark brown discoloration of crown & stem bases reduced tillering smaller heads Photo: Don Mathre, Montana State University

4 Crown Rot - FCR Crown Rot Fusarium spp. Symptoms dark brown lesions at basal node pink discoloration of crown & stem bases death of infected tillers white heads Photo: Nigel Cattlin

5 Take-All Take-all Gaeumannomyces graminis var. tritici Symptoms shiny black roots, crowns & stem bases plants easily pulled from the soil dead plants in patches Photo:,wwww.wa.gov.au

6 Root Rots: A Complex of Diseases Common Root Rot & Crown Rot present every year losses likely average 3-5% severe disease possible - 40% losses have been reported Take-All likely less damaging than CRR and CR ALL root diseases will adversely impact plants under moisture stress

7 Root Rot Survey Work

8 2013/14 Root Rot Survey Minnesota

9 Preliminary Findings of Field Surveys Root diseases were more common than expected we observed symptoms in most fields. Crown Rot (Fusarium spp.) appears to be more prevalent than expected compared to Common Root Rot. This represents a change from older surveys.

10 Seed Treatment Trials

11 Seed Treatments for CRR and CR-control A number of seed treatments are marketed for control of these disease and to help stand establishment. These are unlikely to provide long term benefits to mature plants. There is a lack of data on best practice.

12 Trial Set-up Four on-farm locations throughout MN 2013/14 One location in Langdon, ND for 2014 Randomized complete block design with four replications for each treatment at each site Planted the root rot susceptible cultivar Oxen

13 Stand counts were made at the two leaf stage to determine stand establishment. Plants were assessed at Feeke s Growth Stage 10 for appearance of white heads not due to insect damage. Plant height was measured at heading. Biomass was measured at harvest. 10 plants collected for isolation of fungi per plot. Trial Set-up

14 Seed Treatments Treatment Active ingredients g a.i./lb Control untreated Charter HL triticonazole Stamina pyrachlostrobin Stamina F3 pyrachlostrobin + triticonazole + metalaxyl Dyna Shield metalaxyl Dyna Shield (reduced) metalaxyl (half rate) 0.01 Raxil MD tebuconazole + metalaxyl Raxil MD Extra Imazalil + tebuconazole + metalayxl Tebuconazole tebuconazole Vibrance Extreme Sedaxane + difenaconazole + mefenoxam Vibrance sedaxane Systiva fluxapyroxad Evergol Energy (2014) prothiolconazole + penflufen + metalaxyl

15 Results-MN In 2013, no significant differences were detected in stand counts, plant heights, biomass or yield. In 2014, no differences were detected or yield either between treatments or compared to the untreated control, except in the trials near Fergus Falls and Benson. In Fergus Falls trial tebuconazole reduced grain yield compared to the untreated control (p=0.005). In the trial near Benson Raxil MD increased yield compared to the untreated control (P=0.015). This increase in grain yield was likely the result of a higher initial stand observed with Raxil MD when compared to the control (P= 0.014).

16 Results-ND In 2014 trials were conducted in Langdon with all 13 treatments. Although some white heads were observed in plots, there were no statistical differences for stand, yield or biomass between the seed treatments and the untreated control.

17 Conclusions The preliminary results from this study suggest that seed treatments will not always be necessary for stand protection. In only 1 out of 8 environments across the past two years did one of the seed treatments result in a better initial stand compared to the untreated control. Preliminary data from the fungal isolations from mature crowns and roots show that several fungal species, including Fusarium spp., can frequently be isolated. The decision to use a seed treatment will continue to be a based on the condition of the seed lot; whether loose smut or other seed born disease require control and/or the field history.

18 Conclusions These data suggest that seed treatments are not efficacious throughout the whole growing season. Being able to control and/or reduce infections past the window of efficacy of the seed treatments is important in years when plants are at risk of drought stress. These infected root systems are compromised and are less efficient at taking up water and nutrients. Genetic resistance to crown and root rot may provide better allround disease control with less economic risk compared to a seed treatment.

19 Root Rot Research Next Steps Fungal isolations will be completed to determine if there is any difference in fungal populations between treatments. Establish techniques to screen for genetic resistance to root and crown rots in breeding material. Initial work has conducted in 2014 field trials suggests that producing good disease pressure for crown rot is possible in a field situation. This work will continue in In the disease nurseries soil temperatures and other environmental conditions will be monitored to allow correlation with disease development.

20 Acknowledgements Shaobin Zhong Pravin Gautam Shaukat Ali Minnesota Association of Wheat Growers and Minnesota Wheat Council Amar Elakkad Beheshteh Zagaran Jochum Wiersma Doug Holen Eric Koeritz Peter Samuels Samuel Haugen Rafael Cunha Julia Hagenguth Irakli Koclamazashvili Jillian Reilly Rebekka Schneider

21 Questions? Please contact me at: