News and Tips for You

July 19, 2009

Environmental conditions have been on the dry side (absence of rain and rather low relative humidity) in most canola growing areas of the state during the past four days. These conditions are not favorable for disease development, and that is reflected in the map produced for July 19th. The risk of Sclerotinia is now low for all areas of the state.
Also, enough canola-growing degree days have accumulated since last week so that most canola fields are now ending their flowering period. Such fields do not need spraying. Growers with fields still in early stages of flowering should look for presence of apothecia and should watch the weather conditions this week.

July 15, 2009

Heavy rains that have fallen in parts of Benson, Bottineau, Cavalier, Pennington, and Roseau counties in these past days coupled with the cooler than normal temperatures we are experiencing have elevated the risk of Sclerotinia development in canola in such areas. While the maps represent how conducive the environment is for disease development, other key factors to consider are the presence of apothecia in the fields and the growth stage at which canola plants are right now. If apothecia have not been observed in fields, it is very likely that after these rains some might pop up. This means fields that are still in early flowering stages should be sprayed if they have had a history of Sclerotinia in the past.
Applying fungicides for control of Sclerotinia in fields that are past the flowering stage usually do not produced a positive economic, so  those fields should be OK, especially if they have a history of low or no Sclerotinia problems. However, if is always useful to remind you that additional considerations, like yield potential and commodity price should also be considered when deciding whether to spray or not.

July 13, 2009

• .Delayed plantings due to a cold spring have resulted in approximately 7 to 10 days delay in the initiation of the flowering period of canola. As of July 12 most areas in the upper half of the state started flowering last week.

• Risk levels presented in the maps apply for fields that are at the flowering stage only.

• Prevalence of high risk during nine days (three maps) immediately prior to the beginning of flowering or during the initial stages of flowering have been associated with high levels of disease.

• Fungicides registered for control of Sclerotinia stem rot in canola in North Dakota include: Endura, Proline, Quadris, Quash, and Topsin among chemical compounds. Among biological control products Contans, Polyversum, and Serenade have also been registered, although Contans is better used prior to planting. Consult the latest Field Crop Fungicide Guide for recommended doses or consult with your extension specialist.

June 18, 2009

Tip: From the desk of Sam Markell, Extension plant pathologist. Canola: Some research shows a fungicide application at the 2-4 leaf stage can help manage blackleg. However, planting a resistant variety and using good rotation was found to be more cost effective