Armyworms in Rice
Angus Catchot wrote an article recently about armyworms in wheat. Similar to most years when we have armyworms in wheat, there is the threat of having armyworms in seedling rice. We know of at least one rice field in Mississippi that was sprayed earlier this week. In general, damage from armyworms will not impact rice yields at this time of year unless they are beginning to reduce plant stand. This is especially true in hybrid rice planted at low seeding rates.
Some things to keep in mind about armyworms:
I have not looked at any in person, but they are most likely true armyworms at this time of year. Armyworms tend to become somewhat nocturnal and will crawl into cracks in the soil during the day when it is hot and sunny. As a result, you may find the feeding damage during the day, but not see many worms and think they are gone. In some cases, you may have to dig around in the soil near damaged plants to actually find the worms.
Armyworms in rice tend to be very easy to kill with mid- to low-rates of pyrethroids. However, because they may not be active during the day, it is best to time sprays as late in the day as possible to get the maximum level of control. A pyrethroid spray made before lunch will degrade some in sunlight before the worms become active and may not provide the same level of control as a spray made later in the day.
Seed treatments such as CruiserMaxx Rice or Nipsit INSIDE are not going to provide any control of armyworms in seedling rice. If you happen to have any rice that was treated with Dermacor X-100, you should not have a problem with armyworms. We never say never when it comes to insects, but it is highly unlikely that you will ever have a problem with armyworms in rice treated with Dermacor X-100.
Finally, scout fields regularly and don’t assume that the worms are not there if you don’t see any, especially if feeding damage is present. The youngest rice and fields planted with hybrid rice will be most vulnerable to yield losses this time of year.