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By: Danny Bennett                           


LSD(P=.10) Means Table

Cotton defoliation trials for GAPAC were applied at four locations across the state.   GAPAC consultants picked the locations, trying to choose a representative field for their area.  Treatments were chosen by participating company representatives.   

 Applications were made by Danny Bennett and Lee Dykes.   Treatments were applied with a CO2 spraying system mounted on a tractor sprayer.  All eighteen treatments went out within a three-hour period.  A five-row by 50 ft. treatment was our standard plot size.  The first treatments went out on September 17 (Saturday), and all treatment applications were completed by September 20 (Tuesday).  

 Weather conditions were unusually warm.  Most of the cotton was in good condition to defoliate.  All treatments were more active than typically expected.  Ratings were made at four days after treatment and again at 10 – 11 days.

 Carl Hobbs’ plots in Turner county were an exception.  A 6-day rating was also made because at 4 days, the plots were not progressing as fast as the others were.

 Growers in the area had done very little defoliation application on their fields prior to our defoliation test starting.

  Bleckley County : Spray date --  9-17-05 .  Consultant: Michael Williams.  Cotton at this site was very mature and ready for defoliation.  It was a dryland field, but did receive adequate rainfall and had a good crop set.  Most of the plots could have been picked within five days after the treatment.

  Houston County :  Spray date – 9-17-05 .  Consultant: Paul Brown.  Cotton at this site was irrigated, two-bale, plus potential cotton.  This field was at the right stage for “textbook” defoliation timing.  Treatments performed well at this site because the cotton was in good condition and ready to defoliate.  This was one of the better sites for uniformity.

  Turner County :  Spray date – 9-18-05 .  Consultant: Carl Hobbs.  This field appeared to have suffered from drought conditions for the previous two – three weeks.  The cotton was still under drought stress and defoliates were not taken up (due to plant condition) as well as normal.   We were one week to ten days earlier than when most producers would have normally defoliated.   The condition of the cotton at this site was typical of dryland conditions over the past ten years.  

Seminole County :   Spray date – 9-20-05 .  Consultant: Wes Briggs.  This was irrigated, two-bale, plus potential cotton.  We were probably one week to ten days ahead of typical defoliation timing.  This was an excellent site to evaluate the treatments.  The grower had just irrigated the cotton for the last time on the day before we made our treatments (treated area was furthest along; irrigation was mainly for other areas of the field that were not as far along).  The cotton was not under any drought stress, probably helping the treatments move in faster.  

 Overall comments:   I am still waiting for a “normal” crop year.  Each year is different.  Crop conditions and weather play a major role in determining how defoliates perform.  Recommendations need to be tailored for individual situations. 


Plot data pages:

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