closeup of chickpea plant with ascochyta blight on the stem

It is a very good year for Ascochyta blight on chickpea in the Pacific Northwest and High Plains. I’ve gotten several questions about recommended fungicides and as such, turned to my colleague Dr. Michael Wunsch at the Carrington Research and Extension Center in North Dakota. His results have recently been summarized and are available on his website. From his summary ‘Ascochyta rabiei has developed resistance to the QoI (FRAC 11) fungicides in the northern Great Plains.  Due to fungicide resistance, Quadris (azoxystrobin) is ineffective, and Quadris Opti (azoxystrobin + chlorothalonil) is equivalent to applying chlorothalonil alone (e.g. Bravo Weather Stik, Echo 720, etc).  Chlorothalonil is a good tank-mix partner with DMI fungicides such as Proline (prothioconazole) or Provysol

closeup of chickpea plant with ascochyta blight on a leaf

(mefentrifluconazole) but applied as a stand-alone fungicide is not very effective.’ More detailed information is on his website and I encourage you to check it out. Remember to rotate modes of action where possible or use blends. Include chlorothalonil in early applications before canopy closure as penetration of the canopy later in the season is very difficult and chlorothalonil is a contact fungicide. Remember to follow label instructions including nozzles and water volumes for best efficacy.

Dr. Kevin McPhee, pulse breeder at MSU, was kind enough to provide the list of relative susceptibility of popular chickpea varieties to Ascochyta blight below. R = Resistant; MR = Moderately Resistant; MS = Moderately Susceptible. Note that ‘Resistant’ is a relative term for chickpea Ascochyta, even resistant varieties may require fungicides for optimum disease management.

Sierra                    MS

CDC Frontier      R

CDC Orion           R

CDC Leader         MR or R

Nash                      MS

Royal                     MS

Sawyer                 MS

ND Crown           R

 

Remember that pea and lentil do get a disease called Ascochyta blight but the pathogens are different on each host and do not infect other crops. I have not received any reports thusfar on lentil or pea. Lentil and pea are generally more tolerant of the disease than chickpea.

 

--Mary Burrows

[email protected]; 406-599-9966; @MontanaCropDoc

Click here to print Guidelines for Fungicide Applications on Chickpea for Ascochyta Blight