Defoliation considerations for 2008
Overall I think we are set up for a much easier defoliation season than last year. Below are some reasons why I think this crop is different than last year.
Flex varieties – We have more acreage devoted to Flex varieties this year. Because of the lack of pollination problems with Flex we tend to have a better bottom crop this year. This should result in an earlier crop. It may also cause the crop to open more quickly than you might otherwise think. We need to really be out there looking and cutting bolls so that we don’t delay the start of the defoliation and harvest season. The negative side of having an early crop is that we will more likely have temperatures that are favorable for regrowth. This will especially be important in dryer areas.
Rainfall – Almost everyone has had more rainfall this year than in 2007. This should mean that there is less residual Nitrogen to encourage regrowth, especially in areas with enough rainfall to set a good fruit load.
Nitrogen prices – The high nitrogen prices have caused growers to be more judicious with N. Residual N should be less of a problem for causing regrowth as it has been in the past when N rates where often higher.
Crop condition- As noted above the crop is fairly early overall and in most areas has a good to excellent fruit load. I think this crop will surprise some people who have gotten used to having a poor bottom crop due to pollination problems in Roundup Ready cotton.
There is still a lot of sales pressure on multiple applications for defoliation. I do not think it is wise to attempt pre-defoliation applications before the cotton is ready to defoliate, especially with herbicidal defoliants (Adios, Aim, Blizzard, Def, ET, Ginstar, Harvade, Resource etc.). I think most of the cotton can be defoliated with one application and there is no benefit to driving through your cotton twice. I would try to defoliate with a once-over application. If needed, the PPO’s (Aim, Blizzard, ET and Resource) are an economical choice to clean up with a second application.