Missouri Cotton News
May 2000

Missouri producers planted the cotton crop in record time. Believe it or not we are ahead of most of the other cotton producing states. The crop looks great. A small amount will need to be replanted due to sand damage. Some of the crop is beginning to show drought stress. The color of the leaves has changed from bright green to a blue green. Be on the lookout for thrips. Insects are a problem in other crops already. With the mild winter we probably will have a bad insect year.

Bobby J. Phipps, Ph.D

State Extension Cotton Specialist, Area Extension Cotton Specialist

Replant decisions are becoming more important than ever before. Many varieties are not available for replanting. When replanting, it is difficult to know where the herbicide is located and if more is needed. Replanting should be avoided if possible. The new crop may not be any better than the one being replaced.

Several factors should be considered before destroying the old crop. The date should be seriously considered. Yields drop dramatically after May 20. After mid-June a cotton crop would have little time to mature due to the short growing season in Missouri. Yields and lint quality will be very low after that date. Another crop should be considered in the latter part of June. Late in the planting season certain varieties may be in short supply.

If the stand is fairly uniform over the field and most growing terminals are healthy, it is probably not wise to replant. Plants have buds at the base of each true leaf that can produce a new terminal if the original terminal has been removed. There are not buds at the base of the cotyledon leaves. Cotton appears to just sit for four to six weeks after sustaining major damage. However seldom will a replanted crop catch up with the old crop. It may be equal in stature but will not catch up in maturity. This will be noticeable in the fall just before harvest and is reflected in the yield and grades. A damaged crop will need to be protected from insects and blowing sand because it is very vulnerable in its’ weakened condition. The plants need time to recover from their wounds. Usually there are no products to apply to the crop that will aid in the recovery process.

Cotton has a tremendous ability to compensate for spacing. If two fairly healthy plants per foot are remaining and the stand is fairly uniform, the crop should not be replanted. If it is June then one plant per foot should be satisfactory with a uniform stand. With less than one plant per foot, weed control may be a problem and replanting should be seriously considered.

Replanting one end of a field will present several difficult challenges. It is difficult to determine when to make a pin head application of insecticide for boll weevils. Determining when to quit applying insecticides is also difficult since the cutout date will be different on each end of the field. Irrigation timing is difficult since only one end of the field may be showing drought stress. Timing of application of growth regulators and harvest aid chemicals is almost impossible. Due the differences in maturity in each end of the field it is even more likely to have two-sided bales produced. Usually it is best to replant either all or none of a field if only one end that needs to be replanted. The decision is much easier if one side needs to be replanted since the field can be farmed as two different fields.

If it is very late in the growing season and another crop is replanted then the herbicide residue must be considered.

Usually it is best not to replant a damaged crop so one should give serious consideration to leaving the old crop. There is no guarantee that the replanted crop will be any better than the old crop.

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