A few years ago, a Saskatchewan farmer applied fungicides to a lentil crop to stop a common disease in the pulse crop- anthracnose. After waiting for the appropriate period for the fungicide to be effective, the farmer checked his lentil crop. The fungicide was not effective.
Fungicide manufacturer BASF was notified about the situation, and the company confirmed that the crop was subject to a type of anthracnose that was resistant to Group 11 strobilurins fungicides.
BASF furthered investigation on the discovery with a lentil field survey in Saskatchewan. Many fields were discovered as Group 11 fungicide resistant.
It is not unusual to find a small level of resistance throughout the province, but it is undetermined how the Group 11 Resistant anthracnose will affect growers. So far, there have been few reports of a decrease in crop performance.
Agriculture Canada, Saskatchewan’s ministry of agriculture, and private agronomists confirmed that because lentil fields in Saskatchewan have a combination of different anthracnose, the disease is less harmful to the crop’s yield. Strobilurins can control some of the pathotypes, but not the others.
In 2018, anthracnose was detected in 74 percent of Saskatchewan fields. In 2019, 92 percent of lentil crops surveyed had anthracnose. Anthracnose causes leaf loss, yield loss, and plant death.
The question for many crop farmers is if it is reasonable to use a Group 11 fungicide. With an assorted amount of anthracnose in the majority of fields, the decision is not simple. Group 11 fungicides will not affect the genetically mutated insensitive anthracnose, but it does not mean that it will have no benefit on the field.
Part of the agronomist communities may suggest to growers to stop using the fungicide to reduce the risk of the situation getting worse. A fungicide with other modes of action such as a Group 11 and Group 3 or Group 7 would be sensible. There are many different options to protect growers’ crops. Group 11 fungicides have many merits for crops; standability and plant health are more secure when using the product.
It is highly suggested that lentil farmers should not only apply a fungicide that contains Group 11. To scout the risk of fungicide, growers should assess their crops for symptoms of the plants, the density of the plant stand, the weather forecast over five days, and the number of days with rain over 14 days.
Although there is resistance to fungicides, growers will find that the situation is manageable. Using fungicides smartly, rotating crops and intercropping are tools to ensure a healthier crop and bountiful yield.