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Williamson
County
Result Demonstration Report 
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Beltwide Cotton Harvest Aid Evaluation
Cooperator:
Archie Abrameit
Dale A. Mott
EA-IPM
Ron Leps
Extension Agent-Agriculture
Robert Lemon
Texas Cotton Specialist
Thrall, Williamson County, Precinct #4
SUMMARY: Ten harvest aid treatments were applied on August 3, 2001 on cotton just east of Hutto. Treatments containing the products Dropp and/or Ginstar generally provided the best defoliation. Also, the same treatments did not exhibit any regrowth through 10 DAT as did the desiccants.
OBJECTIVE: The effectiveness of cotton harvest aid vary from season to season and even within a season based on various environmental factors. The purpose of this study was to evaluate the performance of 10 potential harvest aid treatments under the present environmental conditions.
MATERIALS & METHODS:
Treatments were applied on August 2 on a field of DP 20B cotton that was planted on April 20. The field is about 3 miles East of Hutto on CR 132. The cotton was on 38" rows and plots were 4 rows wide and approximately 150' in length. Treatments were put out with a Spider Spray Trak at 3 mph. The initial treatments were applied on August 13. Two 11002 nozzles were used per row with 50 psi.
RESULTS AND DISCUSSION:
Def @ 8 oz/ac plus Dropp @ 0.1 lb/ac provided the best defoliation of all the treatments at 10 DAT with a rating of 95% defoliation (Table1). Ginstar @ 6 oz/ac, Ginstar @ 3 oz/ac plus Dropp @ 0.8 lbs/ac, and Aim @ 0.67 oz/ac each provided 90% defoliation at 10 DAT. Cyclone Max @ 16 oz/ac plus Ammonium Sulfate @ 17lbs/100 gal of water had the lowest defoliation rating at 10 DAT with 35% defoliation.
Although the Cyclone Max @ 16 oz/ac plus Ammonium Sulfate @ 17lbs/100 gal of water had the lowest defoliation rating, it did provide the highest dessication rating of 70% at 7 DAT.
It was noted that each of the Cyclone Max and Aim treatments had basal and terminal regrowth at the 10 DAT rating.
At 7 DAT, the Harvade + Def + Prep treatment provided the best percent defoliation , 81.3, of the treatments (Table 1). At 14 DAT, the Def + Dropp treatment provided 93.8% defoliation, ET-751 + Ginstar + Prep + COC, and Aim + Prep+ COC, followed by Aim +COC, each provided 88.8% defoliation, all of which were significantly better than the other treatments. None of the treatments provided any significant level of dessication. The Def + Dropp provided the highest percent Performance at 14 DAT, 89.3.
Table 2 lists percent terminal and basal regrowth at 21 DAT. None of the treatments had a high level of regrowth at that point.
Table 1. Percent Defoliation and Dessication at 7 DAT and 14 DAT and overall Performance
Thrall, TX. 2001
| Treatment | Rate | % Defoliation 7 DAT | % Desiccation 7 DAT | % Defoliation 14 DAT | % Desiccation 14 DAT | Performance 14 DAT |
| Untreated | 0.0 f | 0.0 c | 20.0 e | 0.0 d | 0.0 g | |
| Def | 0.56 LB/A | 58.8 b | 8.3 b | 56.3 c | 0.3 d | 53.8 d |
| Prep | 0.05 LB/A | |||||
| Dropp | 0.05 LB A/A | |||||
| Harvade | 0.31 LB/A | 81.3 a | 10.5 b | 81.3 b | 1.3 c | 77.5 b |
| Def | 0.56 LB/A | |||||
| Prep | 1.0 LB/A | |||||
| COC | 1.0 PT/A | |||||
| Dropp | 0.05 LB/A | 28.8 de | 3.8 c | 40.0 d | 0.0 d | 38.8 ef |
| Prep | 1.0 LB/A | |||||
| Def | 0.56 LB/A | 43.8 c | 3.5 c | 46.3 d | 0.0 d | 45.0 e |
| Prep | 1.0 LB/A | |||||
| HM2047 | 1.0 LB/A | 20.0 de | 2.5 c | 41.3d | 0.0 d | 36.3 f |
| Prep | 1.0 LB/A | |||||
| Def | 16 OZ/A | 72.5 a | 18.8 a | 93.8 a | 0.8 cd | 89.3 a |
| Dropp | 0.2 LB/A | |||||
| ET-751 | 1.6 G/A | 31.3 cd | 3.5 c | 76.3 b | 1.5 bc | 70.0 c |
| Prepp | 1.0 LB/A | |||||
| COC | 0.5% V/V | |||||
| ET-751 | 1.2 G/A | 72.5 a | 22.5 a | 88.8 a | 2.3 b | 82.5 ab |
| Ginstar | 0.05 LB/A | |||||
| Prep | 1.0 LB/A | |||||
| COC | 0.5 % V/V | |||||
| Aim | 0.015 LB/A | 16.3 e | 3.8 c | 88.8 a | 3.5 a | 83.0 ab |
| Prep | 0.75 LB/A | |||||
| COC | 1.0 % V/V | |||||
| fb Aim | 0.015 LB/A | |||||
Mean comparisons performed only when AOV Treatment P(F) is significant at mean comparison OSL
Table 2: Terminal and Basal Regrowth. Thrall, TX 2001.
