Arkansas
Arkansas Rice: Out of the Frying Pan, Into the Fire
Rice stink bug. Picture: College of Arkansas
I noticed a graphic at present that confirmed the previous month has been the driest of the previous 130 years. So, I don’t assume we’re overstating simply how dry it’s.
The long-term forecast alluded to final week seems to be occurring. I very a lot need one thing constructive to report. However, should you’re bored with my doom and gloom, skip the remainder of this part and soar beneath to different sections!
The subsequent 10 days appear to be the most popular of the 12 months up to now, with a string of 100-degree days and nighttime lows staying at or above 75 levels. I don’t wish to have rice heading subsequent week, however we’re making our method into increasingly fields hitting that time.
As soon as we start to high 100 levels in the course of the day, I’m involved with it affecting pollination. Most problematic although, are the nighttime lows. When now we have 5+ consecutive nights of 75 or higher, it could actually affect pollination throughout flowering in addition to our high quality throughout grain fill. Relying in your actual location and climate supply, the subsequent 10 nights aren’t anticipated to fall beneath 75. Some nights might not fall beneath 80. Yeesh.
Holding cool water transferring by means of the sphere may assist, however solely minimally. Chilly nicely water isn’t going to actually change the microclimate a lot above the water line to assist the rice heads. However, it may assist to scale back the general stress on the plant from the excessive temperatures.
I do know we’re all doing all we are able to to irrigate all we are able to, so there’s little chance of maintaining water operating someplace once we may transfer that water supply to a different area that wants it, however it’s one thing to think about should you had the capability to do it.
Tell us if we may also help.
Managing Rice Stink Bugs in 2022
We now have obtained a number of calls this week on fields beginning to head and having over-threshold ranges of rice stink bugs (RSB) in them. To be trustworthy we had been anticipating the numbers to be increased than what’s being reported. Based mostly on what we noticed in wheat a number of months in the past and what now we have been seeing on native grasses for the previous a number of weeks, we’re in all probability fortunate the numbers are as little as they’re.
A lot of the reviews now we have obtained have been 10-15 RSB per 10 sweeps with the occasional 25-30 per 10 sweeps. Most of that is in all probability as a result of quantity of barnyardgrass heading proper now. RSB appears to want it over rice. As soon as it dries down although, rice would be the solely recreation on the town.
The way in which issues are shaping up now, hopefully by the point the barnyardgrass does dry down a big proportion of our rice might be headed and can dilute the RSB populations to manageable numbers.
For the previous couple of years, now we have performed assays on RSB to check for resistance to lambda-cyhalothrin (Warrior II, Lambda-Cy, and many others.). Our assays up to now this 12 months have proven between 65% and 75% management with a 1X charge of lambda, which is down from final 12 months (90-100%). Earlier this week we sampled some massive block research evaluating Warrior II and Tenchu.
At 3 days after utility the Warrior II plots averaged slightly over 60% management and Tenchu was higher than 90%. No nymphs had been current on the time of utility or once we sampled this week, so its arduous to say if it’s simply poor management with the Warrior II or if there was some reinfestation. There’s a very brief residual with lambda. Odds are it was each.
So, what does that imply for administration of RSB this 12 months?
Lambda nonetheless has a slot in many circumstances. Take into account although, you can not anticipate greater than 60% management and, in lots of circumstances, late within the season throughout 2021 it was a lot decrease. For those who do spray lambda our suggestion is to scout these fields inside 3-4 days after utility to find out the extent of management you bought.
If nymphs are current whenever you spray and likewise 3-4 days after utility, then that may be a signal of poor management. With that being mentioned, if it’s all adults that would imply you bought reinfested.
What are our different choices?
Proper now, the one non-pyrethroid choices accessible are Malathion and Tenchu. Carbaryl can be labeled, nevertheless many international ports take a look at for it so we don’t suggest spraying it.
So far as Malathion goes, it has appeared good in our plots over the previous a number of years, nevertheless we obtained a number of reviews final 12 months of parents not pleased with it. It has a shorter residual than lambda however appears to have extra constant knockdown than lambda.
In our plots it has taken 7-10 days to see nymphs begin exhibiting up behind a Malathion utility. Tenchu is an alternative choice, nevertheless it is going to be troublesome to seek out. Up to now we haven’t seen an enormous distinction between Tenchu and lambda in addition to worth. The previous two years nevertheless, it has appeared a lot better than lambda.
Much like Malathion it often takes 7-10 days to see nymphs behind Tenchu purposes, and in some circumstances, now we have gotten for much longer management.
Backside line with both of those merchandise is we are able to’t afford to spray them twice. The price of Malathion is round $10 per acre for 32 ozand Tenchu is $12 for 8 oz. If we’re going to spend that type of cash on RSB our suggestion is to not spray till we’re primarily mushy dough. That might put us on the tail finish of the second week of heading into the third week of heading.
With that being mentioned, in case you are operating 20+ RSB per 10 sweeps throughout flowering and milk you could wish to take into account an utility. We now have completed a variety of work taking a look at spray timing once we reevaluated our threshold, and we not often see yield losses from RSB, however peck is extraordinarily constant.
For those who can trip these populations by means of the flowering and milk stage and make one utility of a product like Tenchu at mushy dough, more often than not that may get us to the end line.
Tell us in case you have any questions or want something. We are going to replace everybody weekly with what our assays and area research are exhibiting, and if something new is accessible for RSB. Additionally please contact us should you see a failure with lambda so we are able to make a group to conduct resistance assays.
Illness Replace
Sheath blight: Simply two weeks from synthetic inoculation, sheath blight in our experimental plots has moved up near 50% of the cover peak in CL 163 (Fig. 4). That is indicative that the climate is heat and humid sufficient to favor the illness to progress.
Proceed scouting for well timed motion. Morning dew on leaves makes the micro-environment favorable to sheath blight and blast. Fig. 5 is an image taken in our experimental area taken at 10:30 a.m yesterday.
Threshold for fungicide utility towards sheath blight: 35% or extra constructive stops for VS (very vulnerable) and S (vulnerable) rice and 50% constructive stops for MS (reasonably vulnerable) rice.
Blast: In 2022, we obtained the primary report of leaf blast on Titan from Arkansas County. Neck and panicle blast, if extreme, may cause close to 100% grain yield loss. If leaf blast is detected early within the season on a vulnerable selection, neck blast is usually predicted and at the least a one-time protecting fungicide is justified.
Nonetheless, the absence of or incapacity to detect leaf blast on a vulnerable selection in a area with a historical past of blast doesn’t assure that neck and/or panicle blast received’t present up.
Be aware that the pathogen spores that may trigger blast might be carried by wind and makes blast unpredictable.
Protecting Actions for fields with a historical past planted with blast vulnerable rice:
- Improve flood depth to at the least 4” depth. Leaf blast usually is suppressed by enough flood depth.
- Hold the water of at the least 4” deep everlasting till time to empty for harvest.
- If it’s a vulnerable row rice or water is proscribed to lift flood depth, as much as 3 times fungicide utility could also be required relying on the extent of leaf harm and the components that favor blast. Proceed scouting for leaf blast. No threshold has been established for blast since fungicides must be protecting. Keep in mind late season blast is managed with strobilurin fungicides containing Azoxystrobin or Trifloxystrobin.