Flower thrips are being observed in canola. Thrips are tiny (1 mm), elongated insects with rasping-sucking mouthparts that feed on canola buds and pods. Damage symptoms are easy to spot since the pods become curled up and twisted, and drop prematurely. Damaged pods are most common in field edges and usually non-economic in canola.
Canola harvest will start soon. There are two main methods of dealing with canola: swathing the crop or straight combining.
Swathing canola at the right stage of ripening reduces green seed content and the risk of seed shatter losses. During the warm summer months it is important to observe fields every few days when the seed color starts changing in the first formed pods, on the bottom of the main stem.
The field may not ripen uniformly so to determine when the canola is ready to swath, examine plants from different parts of the field. The stage of maturity, even in a uniform maturing field, may vary from plant to plant and from area to area within the field. Also consider differences between low-lying areas, available soil moisture, and soil types.
To determine maturity, examine only pods on the main stem. Seeds in pods on the bottom third of the main stem were formed first and will turn color much sooner than seeds in the pods on the top third of the plant. When the overall moisture content of seed from the total plant averages 30 to 35 percent, about 30 to 40 percent of the seeds in pods on the main stem will have changed color or have started to change color. Seeds with only small patches of color should be counted as color-changed. To obtain the optimal yield potential and quality, the seed color change should be around 60 percent. For more information about swathing and harvesting see NDSU Extension publication Swathing and Harvesting Canola – A1171.
Diquat is labeled for use as a pre-harvest desiccant in canola. Producers can maintain good canola yield potential and quality if the diquat application is timed properly and the crop is harvested in a timely manner. Apply the desiccant when 60 to 75 percent of the seeds in the pods have started to turn color. Research has shown that when the desiccant is timed properly, crop quality parameters, including canola yield, test weight, oil content, seed loss, green count and grade, generally were similar for desiccated canola compared with swathing. When using a desiccant always follow labeled instructions.