Result Demonstration/Applied Research Report

2005 Tom Green County

Cotton Harvest Aid Demonstration

Cooperators: Doug and John Wilde

Rick Minzenmayer, Extension Agent - IPM for Runnels and Tom Green Counties

Steve Sturtz, Tom Green County Extension Agent - Agriculture and

Dr. Billy Warrick, Extension Agronomist (San Angelo, Texas)


    Twelve treatments were applied over the top of cotton on September 16 to prepare for harvest. The plot was established on Doug Wilde’s Farm located 0.5 miles south and 0.5 miles east of the intersection of Farm Road 388 and Loop 306 east of San Angelo, Texas. The chemicals were applied to FiberMax 989 BG2/RR cotton that had 60 to 70 percent of its bolls open. Leaf shed was less than one percent when the plot was established. When these plots were evaluated on September 28, 2005 (12 days after the treatments were applied), most of the treatments resulted in an increase in open bolls, leaf defoliation and leaf desiccation.


     In the Concho Valley Area of Texas, cotton is usually planted starting in mid-May. Because of this planting date, many producers do not use harvest aids to terminate the cotton. When growing conditions are favorable, most of the cotton in this area is ready for harvest thirty days before the first killing freeze. The delay in harvest reduces the income of farmers due to the loss of lint yield and fiber quality. Even though the cost of several of the harvest aid treatments are expensive, there is usually a product that is economically justified that can be used effectively for crop termination. The intent of this field test is to: 1) determine the effectiveness of harvest aids at defoliating, desiccating, and opening bolls on cotton 2) provide producers the opportunity of observing how effectively the harvest aid materials work, and 3) determine the economic feasibility of using the harvest aid material.

Materials and Methods

Cooperating County Producer:           Doug and John Wilde

Location:                                            0.5 miles south and 0.5 miles east of the intersection of Farm Road 388 and Loop 306, east of San Angelo, Texas

Crop Production Information:

            Variety Planted:                     FiberMax 989 BG2/RR

            Planting Pattern:                    Planted solid on 40 inch rows

            Irrigation:                               Drip Irrigated

            Number of Irrigations:            Throughout the season

Harvest Aid Application Information: 

            Date Applied:                         September 16, 2005

            Wind Speed:                           5.0 to 6.0 miles per hour

            Wind Direction:                      East by Northeast

            Air Temperature:                    79 to 830 Fahrenheit

            Relative Humidity:                 66 to 75%

            Carrier:                                   16.0 gallons of water per acre

            Pressure:                                 32 pounds per square inch

            Nozzle Size:                           11002 extended range flat fan over the top of each row and one 8002 Extended Range nozzle on each side of the row.

            Boom Height:                         38 inches

            Cotton Height:                        30 inches

            Ground Speed:                        4.0 miles per hour

            Application Device:               Self propelled rig with 13.33 foot boom

            Plot Size:                                13.33 feet X 60 feet

            Test Design:                           randomized block design replicated three times

Plant Information

     At the time of application, the upper most cotton bolls were cross-sectioned and the seed coats were dark and the cotyledons well developed. Cotton height ranged from 28 to 32 inches. Plants showed no sign of stress and leaf defoliation was less than one percent.

Results and Discussion

  The cotton at the time of application was 60 to 70 percent open with most of the remaining bolls being mature. The application of the harvest aids did impact boll opening, percent defoliation and percent desiccation. Several factors contributed to the success of the harvest aids applied, these include: 1) The cotton was mature; 2) Chemical coverage was excellent due to gallonage, pressure used, and wind; 3) Air temperatures for the 12 days after application were warm enough to allow for good cotton plant response. Leaf defoliation was higher than the check in all treatments and the increase ranged from 68 to 85 percent on September 28, 2005 (12 days after the treatments were applied). None of the desiccation was high enough to be a concern. The data collected on September 28 is reported in Table 1.

Table 1. Tom Green County Cotton Harvest Aid Test, Doug and John Wilde,

September 28, 2005 (12 days after treatments were applied)
(Linked pictures to each treatment name are four rows wide with the sign in the left row)

Harvest Aid

Chemicals Applied

(4 rows of each)

Rate Applied

Per Acre

Cost of

Harvest Aid

 Per Acre


Open Bolls





Finish 6 Pro +

21 oz. +

4 oz.

$10.98 +


96.67 ab

95.00 a

1.33 de

Ginstar + Prep

5 oz. + 16 oz.

$7.40 + $4.13

96.67 ab

95.00 a

1.667 de

ET + Prep +
Herbimax (C.O.C.)

1.5 oz. + 21 oz. +

1% v/v

$3.75 + 5.42 +


97.00 a

90.67 a

4.67 cde

Def + Prep

16 oz. + 16 oz.

$5.50 + $4.13

94.67 ab

89.00 ab

2.67 de

ET + Gramoxone Max +
Herbimax (C.O.C.)

2 oz. + 5 oz. +

1% v/v

$5.00 + 1.37 +


97.67 a

87.67 abc

9.33 bc

Prep + Gramoxone Max +
Herbimax (C.O.C.)

16 oz. + 5 oz. +

1% v/v

$4.13 + $1.37 +


95.33 ab

83.00 bcd

10.67 bc

Aim + Gramoxone Max +
Herbimax (C.O.C.)

1 oz. + 5 oz. +

1% v/v

$5.47 + 1.37 +


98.33 a

80.67 cd

14.33 ab

Gramoxone Max +
CottonQuik +
Herbimax (C.O.C.)

5 oz. +

32 oz. +

1% v/v

$1.37 +

$6.02 +


97.33 a

79.00 d

17.33 a

Resource + Prep +
Herbimax (C.O.C.)

8 oz. + 21 oz. +

1% v/v

$6.00 + $5.42 +


96.33 ab

78.00 d

6.67 cd


7 oz.


88.33 de

95.00 a

1.67 de

Aim + CottonQuik +
Herbimax (C.O.C.)

1 oz. + 32 oz. +

1% v/v

$5.47 + $6.02 +


92.67 bc

82.33 bcd

5.33 cde

ET + CottonQuik +
Herbimax (C.O.C.)

2 oz. + 32 oz. +

1% v/v

$5.00 + $6.02 +


90.00 cd

80.67 cd

5.67 cde




85.00 e

10.00 e

0.00 e


      NOTE:       In Table 1 the individual or combination of letter a, b, c, d, or e shown beside the number are to indicate statistical significance. There is no statistical difference between numbers that have the same letter (even when there appears to be a large difference in results between the materials applied).

     When these plots were evaluated on September 28, 2005 (12 days after the treatments were applied), most of the treatments applied had a significant difference in boll opening, leaf defoliation and leaf desiccation.

     Prior to making any application the cotton plant was examined closely to determine if regrowth was occurring. Since most harvest aids are contact materials, nozzle type, nozzle configuration, volume of water applied and pressure are important considerations. One of the better nozzle arrangements was used in this

plot. It consisted of one nozzle over the top of the row and drops in the furrows with one nozzle spraying each side of the plant. The volume of water and application pressure should be high enough to get good coverage on the top and bottom portion of the leaf and penetrate the canopy enough to properly cover the axilary and terminal buds, as well as the bolls.                                       

      No regrowth had developed enough to be a concern at harvest time. However, some of the materials applied are known to be better at desiccating or removing juvenile growth. These include Aim, ET, Ginstar, and Resource.

     Increased boll opening was noted in the plots where ethephon was applied, either as Prep or in CottonQuik. Also, boll opening was increased in plots where five ounces of Gramoxone Max was applied.

     Please note that a crop oil concentrate was used in tank mixes that contained Aim, ET and Resource. For maximum performance with these products that is an important part of the tank mix.

Economic Analysis

     This test can be used to document the results obtained from the use of harvest aids. If the same treatments are consistently at the top of the list for several years, then producers may want to incorporate those treatments into their cotton production program. Several of the treatments were in the 6 to 10 dollar per acre range and the use of these treatments should result in increased profits for producers. It is important to remember that a higher lint yield is not the only way of increasing profit from the use of a harvest aid. Other factors include: timely harvest, improved fiber quality, improved harvesting efficiency, and higher percent lint turnout at the gin.


I want to take this opportunity to thank Doug and John Wilde for their help in plot establishment and management.

I would also like to thank the companies that provided the chemicals for this harvest aid test. These include:

            - Bayer CropScience provided the Def, Ginstar, and Prep

            - DuPont who provided the CottonQuik

            - FMC Corporation who provided the Aim

            - Syngenta Crop Protection, Inc. who provided the Gramoxone Max

            - Nichino America who provided the ET

- Tri-State Chemical DBA United Agra Products (UAP) who provided the

               C.O.C. (Herbimax)

            - Valent USA Corporation who provided the Resource

Trade names of commercial products used in this report are included only for better understanding and clarity. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Texas A&M University System is implied. Readers should realize that results from one experiment do not represent conclusive evidence that the same response would occur where conditions vary.