July 3, 2014 No. 2014-17
Dr. Jarrod Hardke, Dr. Gus Lorenz, Dr. Bob Scott, & Dr. Yeshi Wamishe
More record-breaking rainfall this week. I don’t see anyone standing up to collect a medal for it though. The majority of rice has reached the reproductive stage and midseason fertilizer applications are being made.
Few can remember a year quite this difficult. Just when we think it can’t get any stranger, we’re reminded that we’re just playing in someone else’s sandbox. I suppose it’s best that we can’t control the weather – we’d never agree on it anyway.
When making decisions about when and how much midseason nitrogen to apply – keep in mind how long it’s been since your preflood application went out. If it’s been less than 3 weeks – wait to pull the trigger, the crop is still using what you gave it before. You can get a response to midseason N out to 14 days after green ring – if the rice still needs N (a response is not guaranteed).
USDA-NASS released its updated acreage projections on Monday (Table 1). Total rice acres for the state have been increased from 1.52 million to 1.57 million acres. Hitting the 1.5 mark shouldn’t be surprising – stop the truck anywhere in the Delta and you’ll see a rice field. Medium grain acres have increased in both number and percent of the acreage over last year, with NASS projecting 190,000 acres. We may actually come in over 200,000.
This week nearly all rice in the state should be at or approaching internode elongation. The big rollout of headed fields should start next week (Table 2).
Table 1. USDA-NASS estimated rice acreage for U.S. in 2014 (released June 30, 2014).
*Arkansas: 1,380,000 long-grain
Table 2. Percent of rice acres set to reach 50% heading during listed weeks of 2014 according to DD50 enrollment.
|July 26 – Aug 1||10%|
Out Standing in Your Field
Fields Under Water
For rice that has gone under water – it’s not the end of the world. Many factors determine how much impact the flooding has on submerged rice. The clarity of the water (how much light gets through); water quality; length of time the rice is submerged; and relative health of the rice at the time it is submerged are involved in how much the crop is affected.
It goes without saying that we want to get the water off as soon as we can. If the water is extremely murky, or if the rice had issues at the time it went under, then it’s more urgent that we get the water off immediately. Then addressing blown or worn levees will be the next problem to worry about.
Rice water weevil numbers are high this year in many spots of the growing region. Unfortunately, the flood is going on many fields later than usual due to weather conditions. From our research and observations we know that if it has been 30-40 days since planting and you are just getting the flood on, CruiserMaxx and NipsIt insecticide seed treatments are not going to hold RWW. Dermacor will still be working.
Fields flooded for 14-20 days: If there are areas that don’t look right, check for RWW larvae. If RWW found, the only option is to drain the field and keep it dry until soil cracking. Not a great choice but it’s the only control option if weevils are bad enough – no insecticide, fertilizer, or snake oil is going to provide relief.
Fields going to flood now: Figure the days on your fields to see if you’re 30-40 days after planting. If you’re past that and RWW scarring and adult activity are high, a foliar application of a pyrethroid might be called for (Mustang Max, Karate Z, Declare). Timing of the application is critical – it must be made 5-7 days after permanent flood. If later than that, keep the insecticide in the jug.
So what is a lot of activity you might ask? If 50% of new leaves have scarring and adults are present – consider a foliar application. If you miss the foliar application timing, your only option then is to drain the field until the soil cracks to prevent weevil damage. Most growers aren’t crazy about doing that as it is costly and may impact weed control and fertility.
Remember if you used Dermacor it will still be active. It is much less soluble and binds to the seed a lot more than the neonicotinoids (CruiserMaxx and NipsIt). Dermacor doesn’t slow adult scarring as much as other seed treatments so don’t assume it isn’t still there even if you see scarring on the leaves.
Fall armyworm activity has been extremely high this year and rice fields should be scouted for developing infestations. They have moved from south Arkansas and are hitting central and north Arkansas now. Use common sense on deciding whether or not to treat, just the presence of worms is not enough to treat. If they are causing substantial defoliation in spots or edges of the field then treat.
Rice stink bug activity appears to be fairly high this year too. We are seeing them in wild hosts everywhere right now. The first fields to begin heading will probably see treatment level type numbers so don’t let them sneak up on you guys who got some fields planted early.
This is a critical time to get out there and scout fields so make the best of it and walk those fields.
As mentioned last week, disease problems are getting into gear. Warm, humid days with frequent rainfall are the recipe for disease development and increase. A few pictures are included here as reminders for some symptomology to continue to be on the lookout for. Scout those plants from top to bottom!
A field in Woodruff Co. (Picture 5) had a combination of a brown cast in the upper canopy and a yellow cast in the lower canopy – looking from a distance. The brown cast was the result of spotting from herbicide damage and the yellow cast was from the death of lower leaves. In general, the rice appeared stressed and such fields need frequent scouting to salvage the crop from considerable disaster.
So far this season, leaf blast has been confirmed in Prairie, Lonoke, Randolph, Arkansas, and Woodruff Counties on Jupiter, CL151, CL152, and Francis. These findings, combined with previous reports of blast in Louisiana and newly this week in Texas, a potential blast outbreak in our area is possible.
Humid conditions were ideal for sheath blight in flooded fields to start infection and enhance its development in susceptible cultivars with thick canopies and excessive nitrogen.
In artificially inoculated trials at Stuttgart, sheath blight increased from a rating of 1 to a rating of 4 over last weekend (0-9 rating scale). Sheath blight has been reported as present in many cultivars across the state. Therefore, frequent scouting and timely management will absolutely be needed this season.
We’ve mentioned before the recommendation that when non-Clearfield fields get hit with Newpath drift the flood should be removed and the soil dried up. Picture 8 shows rice 3 weeks after the drift event and the flood wasn’t pulled. Not looking good right now.
Enroll fields in the DD50 Program here: http://DD50.uaex.edu.
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