Saving money when it comes to trips across the field with a sprayer can be appealing, but it’s important to keep some things in mind when deciding to mix herbicides with other pesticides and/or fertilizers.  With these types of applications, you risk mistakes on application timing, appropriate gallons of water per acre, and possibly using incorrect nozzles, all of which can result in poor efficacy.  However, you also risk crop injury with some of these combinations.  After some questions were raised last year, we completed some work on a few herbicide/insecticide combinations.  In addition, Syngenta released some information in July of 2011 on herbicide/fungicide combinations for their products.   We still do not have a ton of information on every possible combination, but here is what we do know from labels and research.

A media release from Syngenta in 2011 indicates that Syngenta herbicides including Halex GT, Callisto, Callisto Xtra, and all Touchdown brands are safe to be tank-mixed with foliar fungicide applications of Quadris, Quilt, and Quilt Xcel ( http://www.syngentaebiz.com/dotnetebiz/imagelibrary/News%20Release%20FINAL%20(2).pdf ).  Beyond this though, we really do not have a lot of information on herbicide and fungicide tank-mixes.  In the past, there has been quite a bit of injury from herbicide/fungicide combinations, so it’s best to avoid these unless otherwise noted on the label or by the manufacturer.

Halex GT in combination with insecticides and some herbicides may cause severe crop injury and crop loss.  Halex GT may be applied with pyrethroid insecticides (Warrior, etc.).  However, here is a list of DO NOT’S for Halex GT:

1.  DO NOT apply Halex GT postemergence to corn that was treated with Counter (terburfos), Lorsban (chlorpyrifos), or other organophosphate containing soil insecticides.
2. DO NOT apply Halex GT foliar postemergence tank-mixed with any organophosphate or carbamate insecticide.
3. DO NOT apply a foliar organophosphate or carbamate insecticide POST within 7 days before or 7 days after an application of Halex GT.
4. DO NOT apply Halex GT with emulsifiable concentrate (EC) grass herbicides.
5. DO NOT apply Halex GT with suspension fertilizers or UAN as the carrier.

Capreno also has several limitations for certain combinations.  Here is a list of DO NOT’S for Capreno.

1. DO NOT apply Capreno with liquid fertilizers as the main carrier.
2. DO NOT apply Capreno in the SAME SEASON as organophosphate insecticides such as Lorsban (chlorpyrifos), Counter (terbufos), Thimet (phorate), or Dyfonate (fonophos).
3. DO NOT apply foliar organophosphate or carbamate insecticides within 7 days of a Capreno application.
4. There are no restrictions with Capreno applications and the following soil applied insecticides:  Aztec, Regent, and Force (tefluthrin).

In 2011, we conducted a small study to evaluate combinations of POST corn herbicides with insecticides.  The results from this study indicate that significant crop injury and ultimately yield loss may result from some herbicide/insecticide combinations.  As expected, Capreno applied at the 4-leaf stage in combination with a foliar Lorsban application alone (or additionally with Lorsban in-furrow at planting) caused significant crop injury 10 days after application (46% & 63%).   Yield with these treatments (69 & 85 bu/A) was greatly reduced from the highest yielding treatment (166 bu/A).  Insecticide combinations with Halex GT appeared to cause minimal crop injury (less than 10%).  Although once again, the labels do state that Capreno and Halex GT should not be applied in the same season with Lorsban products.  Brigade (bifenthrin) applied foliar with Halex GT or Capreno appeared to be a much safer option with no associated yield loss and crop injury of less than 5%.

This is not an exhaustive list of every restriction.  As always, if you are unsure, complete a tank-mix compatibility test before making an application and read your herbicides labels.