July 14 2011 - Section 18 approved for Tenchu 20SG in LA rice to control rice stink bugs

7/26/2011 9:17:35 PM

Originally posted July 14, 2011 by Natalie Hummel on Louisiana Rice Insects

A Section 18 request has been approved by EPA for the use of Tenchu 20SG on up to 50,000 acres of Louisiana rice. 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, 2011. 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 attached documents for precautions to avoid bee injury.

Treatment threshold: We do not recommend treating until you exceed the recommended thresholds as described in the Section 18 label. 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 the Texas rice production guidelines. Texas entomologists have recently developed a variable economic threshold. You can download the threshold here on page 49 of the linked document. Search for Table 27. The Texas threshold is based on a combination of factors including the projected yield (lb/acre) and the stage of growth of your rice crop. Please contact me if you need guidance in how to use this threshold. We are currently evaluating this threshold in Louisiana rice and may change our thresholds in the future, depending on our data.

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 stinkbug population that is resistant to pyrethoids. We will gather insect samples to run laboratory bioassays.

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 potential 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. Rice harvest has already begun in some portions of southwest Louisiana. I will be posting a survey in the next month to gather more data about milling.

Please contact me if you need additional information.


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