Although the rice stink bug numbers have moderated from the extremely high numbers we saw on early headed fields, we are still seeing 2-4X threshold on many fields as they reach 50-75% heading. These are very manageable levels, and overall, I have received only a few calls on applications not doing what they should. Many fields are in the third and fourth week of heading, so remember at this stage the threshold is one per sweep, or 10 per 10 sweeps. This is the stage where we are watching for developing stink bug numbers and treating as needed to avoid “pecky” rice. There are still a lot of fields that have not even headed yet. These are the fields that got hammered last year, and as early-planted rice fields mature, stink bugs will leave those fields in search of greener, late-maturing fields. As we transition into this situation, continue to scout closely and treat as needed. Remember how quickly fields get covered up with stink bugs. In a matter of only a 2-3 day period, numbers can go from low to extremely high, as we have already seen this year. Pyrethroids appear to be working very well. Remember, when numbers are high use the higher labeled rate, and with the high heat (which I am getting really tired of), we recommend 5 GPA and recommend an adjuvant/crop oil to help application.
One of the questions that starts coming up right now as early fields begin to mature is, “When can I stop spraying/ protecting my rice from stink bug?” As long as rice is in soft dough stage, it is still susceptible to damage from stink bugs. Because of differences in maturity within a field and even on a panicle, this can be a very difficult call. What you need to do is determine the percentage of rice in the field that is still susceptible to damage. Is the field fairly uniform, or do you have those parts of the field that are behind or late? On each panicle what percentage of kernels are hard dough, and what percentage are still susceptible? How bad are the stink bugs? Are stink bugs at threshold, two times threshold, or even ten times threshold? These are the questions you’ll have to answer if you call, so be prepared and be logical.
Scout closely and regularly, spray as needed, and don’t just spray because other folks are. Their rice may be at treatment level and yours may not. No one needs to be anxious to spray. We’ve had plenty of opportunity and will have for a while this season. I don’t know about you, but I’m ready for cooler weather.