July 18, 2014 No. 2014-19
Dr. Jarrod Hardke, Dr. Gus Lorenz, Dr. Yeshi Wamishe, & Scott Stiles
Record-setting low temperatures are the story of the week. Records were set both for nighttime lows and daytime highs. Combined with more rain and flash flood warnings it hardly feels like the middle of July in Arkansas.
A few days of cooler than normal weather will impact crop development, but we’re not extremely cool as far as the plant is concerned. These conditions are great for overall plant health because of reduced stress compared to excessive temps. Hopefully it translates into a yield and quality response.
Common complaints later are fields having an “off” color – folks just feel like the crop should be a darker green color. The condition is widespread enough to lean toward blaming it on environmental conditions. A lighter crop appearance is not an indicator that anything is particularly wrong with the crop. The lack of persistent dry, sunny conditions has likely had an impact on the appearance of the crop.
In most cases these fields are well past midseason and adequate amounts of nitrogen fertilizer have been applied. Attempting to apply additional nitrogen more than 2 weeks after green ring (panicle initiation) has not been shown to provide a yield response. Fertilizer streaking can also give the impression that parts of the field are N deficient – usually they’re just fine but the greenness of the streaked areas can give the false impression of a deficiency.
This week 36% of fields should be reaching 50% heading (Table 1). With the current cooler temperatures, percent of fields heading has been delayed and now more fields will reach this stage in the 3rd and 4th weeks of July. Overall the crop looks great at this point. The extended weather forecast calls for temps to return to normal this week and then hit 100 every day the next week (last week of July). Of most concern are the nighttime lows failing to get below 75 for that entire week while we’re heading – bad for the plants and bad for milling. Let’s hope the forecast changes like it has been all year.
Out Standing in Your Field
The Rice Stink Bugs Are Coming
Earliest fields to heading are reporting threshold levels of rice stink bugs. So far no extremely high numbers have been seen, but the pressure is consistent. Where we don’t have good weed control along field edges and ditches, the stink bugs are staging in very high numbers (Picture 1).
As mentioned last week, insecticide applications prior to heading will not provide control and you can expect to hit threshold and treat again soon after heading. If numbers are high enough, you may have to treat a couple of times this season anyway, don’t waste one early with an unnecessary application.
Threshold – 5 per 10 sweeps first 2 weeks, 10 per 10 sweeps second 2 weeks.
Continued Disease Development
Again wet and cloudy days. The weather appears to increase the concern on blast and sheath blight. There have been more reports of neck blast on Presidio in Texas. More leaf blast has been reported in Arkansas in Monroe, Clay, Lawrence, and White Counties. Again Jupiter and CL151 are the notable cultivars affected. Severe burn from leaf blast was observed in Clay County (Picture 2). The disease reportedly started on the west side of the field closer to the tree line. Blast lesions were apparent on the east side of the 80-acre field with a few hot spots. Remember leaf blast can be well managed with a flood depth of at least 4 inches. The water depth should be held deep throughout the season. In some severe cases fungicide treatment could be required to promptly stop blast activity where it’s causing leaf dry-down and death.
Sheath blight (Picture 4) has slowed down in the past week. However, several fields have been reported to have them. Fungicide applications for sheath blight and blast control; and protective applications for neck blast, kernel smut, and false smut have already started going out. Remember to scout for sheath blight disease. Fungicides are recommended if the disease reaches threshold levels – don’t treatment just because sheath blight is present at the water line.
Picture 5 provides a good illustration of how drift events can happen. There’s a soybean field in the foreground but the aerial application was made to rice behind it in the distance. The application going out was made early in the morning when there was no wind movement at all. The spray remained suspended in the air for some time – where it eventually settled is up for debate. When trying to avoid drift – no wind is bad and too much wind is bad, but some wind actually helps drive the spray into the target.
Speaking of wind, some recent high winds have led to ragged and torn leaves around the state. Split and broken leaves have been easy to find lately (Picture 6). Not of major concern and nothing to be done about it.
Energy Markets Higher This Week
Since making two (2) month lows on Tuesday, crude oil futures have rallied over $4 a barrel and currently trade near $102. In regard to farm diesel prices, heating oil futures have followed crude oil higher over the past four days gaining as much as three (3) cents per gallon. The turmoil in the Middle East and conflict between Russia and Ukraine has provided support to the energy markets. Furthermore, from a technical standpoint (Figure 1), the August heating oil futures contract was due for a corrective rebound after dropping just over 25 cents from the highs made in mid-June.
Over the past year, heating oil futures have consistently found price support near $2.85 per gallon. Current price levels are providing an opportunity for growers to cover their fuel needs for not only irrigation but fall 2014 harvest. For now, the path of least resistance for the energy complex is up as the current world political uncertainties are keeping a fear and supply risk premium in the crude oil market.
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