The IPM team frequently receives questions from our friend PCAs in Yuma regarding possible injury with herbicide combinations. A recent inquiry was about the addition of Prowl (pendimethalin) to Prefar herbicide preplant.
We found in our archives an evaluation that was done in 2002 by Barry Tickes from Arizona Cooperative Extension that addressing this question. The evaluation was located on 8th Street and the Levee in Yuma CO and included the following treatments: Dacthal at 10 and 12lb, Prefar at 6qt alone and with the addition of 0.5pt Prowl. All treatments were applied in 20 gallon/A spray volume as a 50% band on 42-inch beds. The plot size for this experiment was 600 ft. x 8 beds. Immediate incorporation was done with sprinkler irrigation. The results reported are in the following table:
|
Herbicide |
Rate |
Phyto (%Stunting) |
Control: Nettleleaf Goosefoot |
Control: Groundcherry |
|
1. Dacthal |
10lb |
0 |
95 |
90 |
|
2. Dacthal |
12lb |
0 |
95 |
95 |
|
3. Prefar |
6qt |
0 |
30 |
0 |
|
4. Prefar+Prowl |
6qt+0.5pt |
20 |
50 |
0 |
|
5. Untreated |
-- |
0 |
0 |
0 |
|
|
|
|
|
|
As can be seen the addition of 0.5pt of pendimethalin to 6qt of bensulide produced 20% stunting in this case.
