Result Demonstration/Applied Research Report


2002 Conservation Tillage Weed Control Test

Cooperator: Floyd Schwartz
Reagan County

Warren Multer, Extension Agent-IPM and Steve Sturtz Glasscock County Extension Agent; Raymond Quigg, Upton County Extension Agent; Robert Scott, Reagan County Extension Agent; Charles Stichler, Extension Agronomist (Uvalde, Texas) and Dr. Billy E. Warrick, Extension Agronomist (San Angelo, Texas).


Summary

Eighteen treatments were applied to land that was bedded up and ready for planting. A heavy infestation of Russian thistle that was 2 to 3 inches tall and Kochia that was 1 to 1.5 inches tall were present at the time of application. Plots were evaluated at six and 15 days after applications were applied. Valor at 2 ounces per acre controlled 99 percent of the Russian thistle and Kochia in its plot with no emergence of new weeds being observed at a cost of $9.28 per acre for the herbicide it was considered the best treatment for the money in this test.


Objective

Control of weeds that emerge prior to the establishment of the crop being planted is a major challenge faced by producers wanting to incorporate conservation tillage practices. Some of the annual winter and early-spring weeds have been hard to control. A study was needed to evaluate labeled herbicides for controlling Russian thistle (Salsola iberic) and Kochia (Kochia scoparia). Mature Russian thistle and Kochia plants are moved by the wind and as they travel distribute seed for several miles. The result is generally weeds that remove moisture and nutrients from the soil which will result in lower lint or grain yields. Weed contamination from adjoining acreage can be a considerable problem to producers. The purpose of this test is: 1) determine the effectiveness of herbicides at controlling Russian thistle and Kochia, 2) provide producers the opportunity of observing how effectively the herbicides control the weeds, and 3) determine the economic feasibility of applying the herbicides for weed control.


Materials and Methods

Cooperators: Floyd Schwartz
Location: 1 mile north and 1 mile west of the intersection of Farm Road 1357 and State Highway 137.
Herbicide Application Information:

Date Applied: March 27, 2002
Wind Speed: 8.0 to 10.0 miles per hour
Wind Direction: South
Air Temperature: 52 to 700 Fahrenheit
Relative Humidity: 32 to 41%
Carrier: 10.0 gallons of water per acre
Pressure: 32 pounds per square inch
Nozzle Size: 110015 air induction flat fan on 20 inch centers
Boom Height: 12 inches
Ground Speed: 3.25 miles per hour
Application Device: Self propelled rig with 13.3 foot boom
Plot Size: 13.3 feet X 600 feet
Time Applied: 10:30 a.m. until 1:30 p.m.
Test Design: Randomized Strip
Test Plot Evaluated: April 2 and April 11

The herbicides were applied to land that was bedded up and ready for planting. A heavy infestation of Russian thistle that was 2 to 3 inches tall and Kochia that was 1 to 1.5 inches tall were present at the time of application.


Results and Discussion

When the plots were evaluated at six days after application the 2,4-D Ester (Salvo) at 16 ounces plus Valor at 1 ounce; Cyclone Max at 21 ounces; and Valor at 2 ounces per acre treatments had the highest level of Russian thistle control. They ranged from 90 to 96 percent control on control of Russian Thistle. Of these treatments Cyclone Max at 21 ounces had the lowest Kochia control at 80 percent. Data collected seven days after treatments were applied is reported in Table 1.

The evaluation at 15 days after treatments were applied provided additional information (refer to Table 2). The Valor at 2 ounces per acre was controlling 99 percent of the Russian thistle and Kochia with no emergence of new weeds being observed. The 2,4-D Ester (Salvo) at 16 ounces plus Valor at 1 ounce was controlling 99 percent of the Russian thistle and Kochia with emergence of Russian thistle starting to occur. The Cyclone Max at 21 ounces had 99 percent of the Russian thistle and 80 percent of the Kochia controlled, however, numerous Russian thistle and Kochia seedlings were emerging.

Direx 4L alone was not very effective in controlling the weeds in this test. When Direx 4L was combined with other products the level of control was increased in most treatments. Roundup Ultra Max alone provided 57 to 82 percent control, Touchdown IQ provided similar results. The 2-4-D (Ester or Amine) stunted and twisted more plants than it controlled.

The population of weeds were high in this test plot and a minimum of 95 percent control was needed. If control was lower than 95 percent another treatment or plowing would be necessary.

Table 1. Information Collected From Conservation Tillage Weed Control Test Six Days After Treatments Were Applied (Glasscock Co. 2002)




Herbicide and rate per acre

Herbicide
Cost
Per
Acre
Percent
Russian
Thistle
Control
(04/02/02)
Direx at 1.5 pints 4L + COC + Cyclone Max at 1.25 pints $3.61 + $5.86 35%
Roundup Ultra Max at 20 oz. + AMS $7.77 25%
Roundup Ultra Max at 26 oz. + AMS $10.11 5%
Roundup Ultra Max at 20 oz. plus Harmony Extra at 0.4 oz. + AMS $7.77 + $4.60 30%
Roundup Ultra Max at 20 oz. plus Valor at 1 ounce + AMS $7.77 + $4.64 65%
Valor at 2 oz. + COC $9.28 90%
Cyclone Max at 21 oz. per acre + NIS $6.15 93%
Touchdown IQ at 32 oz. +AMS $10.06 25%
Check $0.00 None
Direx at 1 quart 4L + COC + Roundup Ultra Max at 20 oz. $4.81 + $7.77 25%
Direx at 1 quart 4L + COC + 2,4-D Ester (Salvo) at 16 oz. $4.81 + $3.28 40%
Direx at 1 quart 4L + COC $4.81 5%
Direx at 1 quart 4L + COC + Valor at 1.0 ounce $4.81 + $4.64 65%
Direx at 1 quart 4L + COC + Cyclone Max 8 oz. $4.81 + $2.34 5%
Direx at 1 quart 4L + COC + Harmony Extra at 0.4 ounce $4.81 + $4.60 25%
2,4-D Ester (Salvo) at 16 oz. + NIS $3.28 5%
2,4-D Amine (Savage) at 0.5 pound + NIS $1.90 5%
2,4-D Ester (Salvo) at 16 oz. + Valor at 1 ounce + NIS $3.28 + $4.64 96%
2,4-D Amine (Savage) at 0.5 pound + Valor at 1 oz. +NIS $1.90 + $4.64 5%


Table 2. Information Collected From Conservation Tillage Weed Control Test 15 Days After Treatments Were Applied (Glasscock Co. 2002)



Herbicide and rate per acre
(click on treatment to view plot at 15 days after application)

Herbicide
Cost
Per
Acre
Percent
Russian
Thistle
Control
(04/11/02)
Direx at 1.5 pints 4L + COC + Cyclone Max at 1.25 pints $3.61 + $5.86 90%
Roundup Ultra Max at 20 oz. + AMS $7.77 57%
Roundup Ultra Max at 26 oz. + AMS $10.11 82%
Roundup Ultra Max at 20 oz. plus Harmony Extra at 0.4 oz. + AMS $7.77 + $4.60 97%
Roundup Ultra Max at 20 oz. plus Valor at 1 ounce + AMS $7.77 + $4.64 80%
Valor at 2 oz. + COC $9.28 99%
Cyclone Max at 21 oz. per acre + NIS $6.15 99%
Touchdown IQ at 32 oz. +AMS $10.06 86%
Check $0.00 None
Direx at 1 quart 4L + COC + Roundup Ultra Max at 20 oz. $4.81 + $7.77 84%
Direx at 1 quart 4L + COC + 2,4-D Ester (Salvo) at 16 oz. $4.81 + $3.28 53%
Direx at 1 quart 4L + COC $4.81 30%
Direx at 1 quart 4L + COC + Valor at 1.0 ounce $4.81 + $4.64 73%
Direx at 1 quart 4L + COC + Cyclone Max 8 oz. $4.81 + $2.34 25%
Direx at 1 quart 4L + COC + Harmony Extra at 0.4 ounce $4.81 + $4.60 98%
2,4-D Ester (Salvo) at 16 oz. + NIS $3.28 30%
2,4-D Amine (Savage) at 0.5 pound + NIS $1.90 20%
2,4-D Ester (Salvo) at 16 oz. + Valor at 1 oz. + NIS $3.28 + $4.64 99%
2,4-D Amine (Savage) at 0.5 pound + Valor at 1 oz. +NIS $1.90 + $4.64 73%

Economic Analysis

The cost of treatments ranged from $1.90 to $12.41 per acre in this test. The Valor at a 2 ounce rate combined with a crop oil concentrate at a cost of $9.28 per acre for the herbicide was considered the best treatment for the money in this test. It provided 99 percent control of the target weeds and new seedling emergence was not seen 15 days after treatments were applied. The 2,4-D Ester (Salvo) at 16 ounces plus Valor at 1 ounce combined with a non-ionic surfactant is an excellent treatment, however, daytime temperatures and the potential for off target drift is an important consideration.


Acknowledgments

I want to take this opportunity to thank Floyd Schwartz for his help in plot establishment and management.

I would also like to thank the companies that provided the chemicals for this weed control test, these included:

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.