Soybean Looper Control in Late Soybeans

Soybean looper has started to show up in soybean and a few applications have started in some fields. We have several good options to manage soybean looper and all of them should be considered.  Belt has become the go to insecticide for looper control in a lot of situations over the last couple of years.  This is the first year that the new insecticides Prevathon and Besiege have been labeled in soybeans and they are rapidly gaining in popularity.

All three of these insecticides are in the diamide class and have a similar mode of action.  They are and will remain a very important part of soybean IPM programs in Mississippi as long as they continue to effectively control the target pests.  They are very effective for soybean looper control and should be considered in a lot of situations.  However, the diamides may not be the best option for soybean looper control in all situations.  It is important to remember that several other “older” insecticides are still available.

Insecticides such as Intrepid, Radiant, Steward, Tracer, and Larvin are all still labeled in soybean.  All of these insecticides can provide similar levels of soybean looper control to the diamides.  So, when is the best time to use a diamide vs one of these other insecticides for soybean looper control?

When bollworms are in the mix, the diamides are probably the best option in soybean.  Over the last few weeks, a lot of soybeans have been sprayed for bollworms and one of the diamides was used in most of those situations.  Once soybeans are no longer flowering, it is highly unlikely (but not impossible) that bollworms will be in the field.  Therefore, it is a good idea to consider using one of the other insecticides when you are targeting only loopers.  This will help to alleviate some selection pressure for resistance to the diamides.  This is especially important in areas where the diamides have already been used to control bollworm.   The only real advantage that the diamides have over the other insecticides is that they will provide longer residual control of loopers in young beans.  In older beans that are within about two weeks of R7, the other insecticides should provide enough residual control to finish out the season.

Belt, Prevathon, and Besiege are all outstanding insecticides for controlling caterpillars in a lot of crops.  As much as they are being used in multiple crops, it seems inevitable that resistance in one of our key pests will eventually occur.  In terms of soybean looper control, some of the other insecticides will provide similar levels of control, and that is a good area where we can reduce some of the selection pressure on this important class of insecticide.