Using Micro Herbicide-Rates for Weed Control in Sugar Beets in Idaho and Oregon

Aventis, formerly AgrEvo just recently received EPA approval for using Betamix and Progress herbicides for micro-rate applications. Multiple micro-rate applications of Betamix or Progress in tank mixture with reduced rates of UpBeet, Stinger, and modified seed oils (MSO)

Table 1 shows the Betamix and Progress rates that can be used depending on the sugar beet growth stage.

Table 1. Dosage chart for multiple micro-rate broadcast applications.

In addition to the Betamix or Progress, it is recommended to add the following herbicides at the following rates.

UpBeet at 1/6 oz/A (can use up to 0.5 oz/A) plus
Stinger at 1.33 fl oz/A plus
Modified seed oil at 1.5% v/v or a minimum of 1 pt/A.

Grass herbicides can be added to the tank mixture if needed. The rate used depends on the herbicide used.

If using Assure II, the application rate is 4-fl oz/A.
If using Poast, the application rate is 5.3-fl oz/A.
If using Select, the application rate is 2-fl oz/A.

Experience has shown that using micro rates will require three to five applications, depending on weed populations and emergence patterns.

It is recommended that the herbicides be applied broadcast instead of in a band when using micro herbicide rates. Weed control with banded applications of the micro-rates have been less consistent than broadcast applications. If using band applications, it is recommended to use 11" bands.

Timely applications are critical for the success of the micro herbicide rate applications.

The first application should be made when the weeds are in the cotyledon to 2 true leaf stage. Waiting longer can result in poor weed control with these below-label rates.

All subsequent applications should be made at 5 to 7 day intervals. However, this is dependent upon growing conditions. If the temperatures are above normal, these applications may need to be made at 4 to 5 day intervals. If the temperatures are below normal, application intervals made need to be adjusted to 6 to 8 day intervals.

Nozzle plugging, due to herbicide settling out, has occurred in Idaho, but has not been a frequent problem.

To minimize plugging:

a. Spray immediately after mixing.

b. Completely empty the sprayer before stopping for lunch or in the evening.

c. Use nozzle strainers larger than 100 mesh.

d. Acetone works well as a solvent or cleaner for plugged screens.

e. Increase spray solution pH with household ammonia or Quad 7 (AGSCO)

Use the following mixing order to minimize the potential of nozzle plugging.

a. UpBeet

b. Betamix or Progress

c Stinger

d. Modified Seed Oil

Keep in mind that Aventis, Dupont, Dow Agro Sciences, BASF, or Valent does not assume any liability for crop injury or lack of weed control with these micro rates.