PGRO Crop Update (05.09.13)

Field bean desiccation

As well as increasing production costs, there may also be loss of crop from the passage of the sprayer. Desiccation will not advance seed maturity and has a slow effect on green stems. However, if the crop is infested with green weedy material or has a few late set pods which are still green, application of a desiccant will aid combining.

It is important to apply the desiccant at the correct stage of maturity. Application before this stage may result in reduced yield or loss of seed quality.

The most widely used material is diquat. A non-ionic surfactant can be added. Apply when 90% of the pods are dry and black and most of the seed is dry. At this stage, most of the leaves have senesced and fallen, but the stems are still green. The contact action is fast, and harvesting can be carried out 4-7 days later. It can be used on crops for animal feed, human consumption or seed.

Glyphosate is not a true desiccant but can be used as a pre-harvest treatment to control perennial weeds. It must not be used on crops destined for seed.