Originally publish May 7, 2012
This blog was originally post at the Louisiana rice insects blog.
A Section 18 request has been approved by EPA for the use of Tenchu 20SG on up to 100,000 acres of Louisiana rice to control rice stink bugs. Click here to read about biology and management of rice stink bugs. This product will provide an alternative mode of action to the pyrethroids that are currently registered for use in Louisiana. The exemption expires October 31, 2012. The distributor in Louisiana is Mr. Michael Hensgens with G&H in Crowley. According to Mr. Hensgens, the suggested retail price is $24.30 lb at ½#per acre = $12.15/ac.
Rate and restrictions: Please contact your local County Agent for a copy of the Section 18 registration before using this product. Remember that the label is the law! The registered rate is from 7.5 to 10.5 oz of product per acre. A maximum of two applications can be made per acre per season. A seven day pre-harvest interval must be observed. Be aware that this product is toxic to honeybees – read the Section 18 registration for precautions to avoid bee injury.
Treatment threshold:We do not recommend treating until you exceed the recommended thresholds as described on the Section 18 label (the current label reads that you should follow the Texas guideline – this has been amended to reflect LSU AgCenter recommendations in pub 2270). To scout for rice stink bugs in the field, use a 15-inch diameter sweep net, take 10 sweeps at 10 different areas around each field. Count the number of bugs collected after every 10 sweeps and then treat if they exceed the threshold as described in LSU AgCenter Publication 2270. During the first two weeks of heading, treat when there are 30 or more stink bugs per 100 sweeps. From the dough stage until 2 weeks before harvest, treat fields when there are 100 stink bugs per 100 sweeps.
Before we consider applying for an emergency exemption next field season (should we feel it is warranted) we need to gather some specific data. We need your assistance gathering this information.
1. Resistance. Please notify us if you believe that you have a stink bug population that is resistant to pyrethoids. We will gather insect samples to run laboratory bioassays to screen for insecticide resistance.
2. Efficacy. If you use Tenchu 20SG we would appreciate any data you gather on residual efficacy of the product. Data from Texas has indicated that it provides a longer window of activity than pyrethoids. This will potentially result in a reduction of the number of insecticide applications to a field in one season. We will be conducting efficacy trials in Louisiana to measure residual efficacy when compared to pyrethoids. If you’d like to participate in a field demo, please contact your local County Agent and they can work with me to make arrangements.
3. Milling. We also need your assistance in gathering data on milling quality of rice. Specifically, we need more data on reductions taken at the mill in the form of peck and broken grains which is attributed to Rice stink bug feeding injury. Any information you can provide on grade reductions attributed to rice stink bug feeding injury will be appreciated.