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Volume XV no. 11 August 24, 2001
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IN THIS ISSUE: Cotton Insects
Forage Sorghum Agronomy Wheat Agronomy
Problems with cotton insects are almost over for most fields. Late irrigated fields are still vulnerable to plant bug, boll weevil and bollworm damage. Both whiteflies and aphids are rapidly becoming only a minor concern from the standpoint of sticky cotton avoidance. Fall applications for boll weevil eradication start in about ten days for all areas in the High Plains. There are some concerns pertaining to the potential of drought-induced nitrate or prussic acid poisoning in forage sorghum this year. Many growers appear to be pushing the planting window for winter wheat especially early this year with potential problems developing. And finally, there are updates provided on sunflower oilseed pricing and delivery point changes. JFL 
While scattered rain showers have given some irrigated growers a little relief, they have not been good news to the few dryland producers who received significant amounts of rain (regrowth problems and new food source for boll weevils). Let's be honest. For all practical purposes this season is over as far as setting more bolls and protecting potential yield enhancing bolls from insect damage. Most fields, from north to south, have either hit physiological cutout (Nodes Above White Flower of 4 or less) or have past their regions seasonal cutout date ( Hereford=August 2, Plainview=August 8, Lubbock=August 11, and Lamesa=August 15). Obviously all we are interested in from here on out is to preserve bolls and accumulate enough heat units to escape insect damage and set the field up for harvest. Insect pressure on area cotton is still light in most cases, as it has been all season long. Boll weevil and western plant bug numbers are increasing in some fields, banded-winged whiteflies are still with us but no longer increasing significantly, cotton aphid infestations are still "parked", and most bollworm infestations are being kept below treatable levels by weather conditions and abundant predators. Boll weevil activity took a jump last week as more 2nd summer generation adult weevils emerged from infested fruit and spread across the countryside. Since most fields have cutout and have or are in the process of shedding remaining squares and small bolls, adult boll weevils have had to move between fields in search of suitable feeding sites. They can always find a late irrigated field with plenty of squares and small bolls to puncture. This movement kicks up trap catches and insures that there are a few fields with significant weevil damage. But this year these fields are few. And even most of these fields should be close to accumulating 350 heat units past either physiological or seasonal cutout and be entering the "safe zone".If you are one of the few producers who have had to spray weevils to protect bolls, don't stop until all reasonable potential harvestable bolls are safe. Otherwise the first applications will have been an expensive waste. The threshold is around 15% punctured, nickel-sized bolls inspected. Don't check squares as they are few and far between, boll weevils prefer squares, and counts based on a "crashing" square supply will greatly inflate weevil damage estimates, leading to too much unnecessary spraying. Guthion is a good material for ground applications by producers. Methyl parathion or ULV malathion are good for aerial application. GRID trap catches have reflected this latest weevil activity increase as has the Texas Boll Weevil Eradication Foundation's traps. The average increase has been 2.5X, regardless of zone status. The really good news is that active eradication zone trap catches are greatly reduced compared to last year. The reductions for last week were: 99.3% for the Northwest Plains, 99.9% for the Permian Basin and 98.3% for the Western High Plains.Fall spraying starts the week of September 3rd with two new zones entering into eradication: Northern High Plains and Southern High Plains. With low weevil numbers to begin with, these two programs could end up at least one year ahead of schedule. Western tarnished plant bug numbers have increased in selected fields. Heaviest infestations are often associated with peanuts and other alternate host sources. As expected, numbers are highest in late irrigated fields, especially those that are row watered and real lush. Small boll loss can be high from this pest. Bolls are not considered safe until at least 250-350 heat units have accumulated since flower or since cutout. This would have taken about 10-18 days, depending upon your location and situation. Damage appears as black spots or lesions on the outside of the boll. But unless feeding results in penetration as evidenced by warts on the interior of the boll wall or discoloration of developing lint, then don't count these bolls as damaged.Two plant bugs per foot of row as determined by the drop cloth sampling method and 15% damaged bolls is the suggested treatment level. Pyrethroids work well but can flare aphids. Orthene is also an excellent material. Sometimes you can get by with Bidrin, Provado, or Vydate if infestation pressure is not too severe. Bollworm eggs are still plentiful in some fields but for the most part, damaging infestations of caterpillars fail to materialize. The egglay is not over with yet so keep a watchful eye out for increasing caterpillar numbers in lush, late irrigated fields. Between our hot, dry conditions and the activity of numerous predators, not many eggs have produced damaging worms. Pyrethroids are cheap this year but the cotton price is down. These two factors tend to cancel each other out resulting in our ability to continue to use our existing thresholds. Remember that it takes about 450-500 heat units past cutout for a boll to be safe from a small bollworm. Larger bollworms can still penetrate a boll until they can no longer be easily sliced by a sharp knife. Pyrethroids can flare aphids but this appears to be more difficult to do this year than in years past.Cotton aphids remain "parked", with little upward movement in their numbers. Since population growth has been slow to at a standstill, predators have been able to remain on top of the situation. I am still concerned about possible aphid problems but my attention is starting to shift toward the sticky cotton issue rather than actual yield preservation. But so far there appears to be little threat of a sticky cotton problem from aphids this year. Banded-winged whiteflies can be found in many fields but reproduction appears to have decreased with mostly adults present. This is good since nymphs appear hard to control with many of the possible insecticide choices. A pyrethroid plus Orthene or Address appears to still be the best control option. Most of the infestations I have seen are concentrated just below the terminal. I think we are out of the woods as far as yield protection is concerned. Now we must wait to see if a sticky problem will develop. i.e., whitefly infestations blow up as more cotton opens.Beet armyworm infestations have failed to develop this year. Early, high overwintering numbers failed to establish and increase in the face of heavy predation. Beet armyworm trap catches by the eradication foundation are generally down this week. But more importantly, trap catches this year, this past week are down 70% compared to last year. Folks, we dodged the bullet this time. After last year, we were all running scared. I guess my observation of never seeing back-to-back severe beet armyworm years was confirmed. For those that are interested, a tentative defoliation "safe zone" has been established using COTMAN rules. Once a field has accumulated 750 heat units past cutout, yield can no longer be decreased significantly through defoliation. This would apply to both beet armyworms and loopers. JFL
Carmine mites, also known as red mites, are showing up in some area fields. The damage looks like tiny, whitish freckles on a leaf. There is no established economic threshold. However, severe infestations are apparent and often spotty initially. Danitol and Comite II are suggested insecticides. Both carry a 14 day harvest restriction and treated fields can not be grazed or used for hay. PP
Headworms are still with us, and late sorghum crops are still at risk from sorghum midge.
Corn is about done, and some fields have been harvested. Thankfully we escaped most of the major spider mite outbreak north of I-40. Emilio Nino, Pest Management Agent in Castro and Lamb counties, is finding a few fields heavily infested with spider mites. In his words, "when I came out of the field, my shirt was moving". In practical terms, nothing can be done now. The fields already received two Capture applications, the last one 20 days ago.
Drought-induced nitrate and prussic acid poisoning in forages. The showers and rains over the past 2 to 3 weeks have brought a flurry of calls with questions about nitrate and occasionally prussic acid (cyanic acid) in forages. Complete information on these topics was sent into County Extension Offices the week of August 13th. In general, growers have been concerned on two fronts: 1) Can I salvage sorghum or sorghum/sudans that have just been sitting there without growing due to drought? 2) Will quick regrowth of drought stressed plants lead to prussic acid? Nitrates are a concern in forages if they have not been growing. Nitrate may continue to accumulate in plant tissues, especially if N fertilizer was applied, when plants cease to grow due to moisture stress. Nitrate accumulations are typically much higher in the bottom of the plant whereas grazing livestock eat younger, more tender portions. Thus nitrate poisoning is often more of a concern in cut forages as cutting "locks in" potentially dangerous nitrate levels, which will not dissipate. After growth is initiated, forages often return to safe levels of nitrate concentration in the plant. One percent nitrate on a dry weight basis is potentially lethal for healthy animals, 0.5% or pregnant or unhealthy animals. Prussic acid concerns are usually associated with the first hard frost or freeze in the region. But prussic acid can also develop in immediate new growth after plants have been stressed. Given 4-5 days of good growth, prussic acid will dissipate. It will also dissipate in about 3 days from properly cured hay. Samples may be readily tested for nitrate, but prussic acid testing requires special handling of the sample. Call your local Texas Extension Agent for instructions on how to collect and submit a sample. CT 
Is it too early to plant winter wheat? This has been a common question coming into County Extension Offices and the Lubbock Center since early August. Some acres have already been seeded with early grazing in mind. There are several reasons why this is not a good idea, even as of August 22nd. In general, almost without exception, it is simply still too early to plant wheat, no matter how bad a farmer may want grazing. But why? Soil Temperatures: A maximum daily average, 4" depth, for seeding small grains should be at most 85 F and preferably lower. Average daily temperatures at Lubbock and Halfway had cooled to about 82 F around August 15th, but have now already returned to 90 F (find current soil temperatures at http://achilleus.tamu.edu or http://amarillo2.tamu.edu/nppet/petnet1.htm). For comparison, in 2000 average daily soil temperatures did not dip below 85 F to stay until September 14th at Halfway and the 19th at Lubbock. Growers wanting early small grains should fit the planting date to the climate, not the calendar. When soil temperatures are above the 85 F maximum target, successfully achieving a viable stand is more difficult. Yes, decent stands can be achieved at higher soil temperatures, particularly if under center pivot. But at what cost? Steve Winter, Experiment Station-Amarillo (retired), conducted limited research on soil temperatures and small grains forage growth. He found that water use was high (and costly), and overall biomass (forage yield) was not improved by excessively early planting (ca. August 25th). With warmer soil temperatures, frequent irrigation has not maintained survival and plant vigor. The cost of extra water use required for irrigating wheat planted in August vs. saving that cost and planting a little later does not merit early planting. Growers eager to get some early fall grazing might think they are ahead of the game, but a poor stand from heat, etc. in August may never catch up with a crop planted for grazing in early September. Other research in the Panhandle demonstrates that early planted wheat has shorter (poorer) coleoptile length and poorer grain yields, particularly for dryland (too much water use early on during high temperatures, leaving less water for tillering and grain production the following spring). Also, some varieties have too much post-harvest dormancy when soil temperatures are high, which can drastically reduce germination by over two-thirds for some varieties. (Favorable or low PHD, Lockett, TAM 202, Tomahawk; poor or high PHD, Longhorn, TAM 107, Olgallala, Thunderbolt, Triumph 64).What about dry seeding wheat now and waiting for a rain? Again, not a good idea. Too little rain means germination then the seedlings risk drying out. Stands could still be poor simply due to heat. Deep phosphorus for improved wheat forage yields. If growers are so concerned about trying to increase their wheat forage yields (let alone grain yields) by early planting, they may be better served to consider the good Rolling Plains work demonstrating how effectively deep P boosts wheat forage yields. (See 'Deep Phosphorus Banding in Winter Wheat -- A Risk Management Tool for the Southern Great Plains', http://lubbock.tamu.edu then click on 'other crops' and finally 'wheat'). The key is placement of the P 6-8" in the soil so that even in dry times, roots can still take up P.Wheat varieties for grazing. Growers who intend to graze out wheat and would like a beardless (awnless) wheat may consider Lockett, Longhorn, TAM 109, WeatherMaster (WinMaster, WinTex), or the old generic 'Russian' beardless. Lockett is a Texas A&M release bred as a grazing wheat. It has a broad leaf and medium-late maturity. Grain yield has been fair in some trials if in fact a producer changes their mind about graze out. This variety tillers well, but sometimes short awns of 3/8 to 1/2" may develop. May lodge some. Longhorn is adapted primarily for dryland production or grazing. Like Lockett, medium-late maturity extends the grazing season. Some tolerance to wheat streak mosaic and leaf rust. Fair grain yield. Long coleoptile allows emergence from lower soil depths and improves stand establishment on poor soils or seedbeds. TAM 109 is a beardless similar to TAM 101. Very short under dryland conditions. WeatherMaster is maintained by Abilene Ag. Supply. Older derivative of Russian Beardless, this variety does not tiller as well as other wheat, and forage yields are consistently lower than Lockett. 'Russian beardless' is a generic wheat that is not a registered variety, and varies from place to place. Tillering is less. Growers are encouraged to plant seed of specified varieties rather than generics (or bin run seed) where variety is not known. Wheat production tips will appear in next week's FOCUS. Is karnal bunt a concern to South Plains cotton growers? (Yes!) "I won't be growing any wheat for grain..." "I just graze all of the wheat I have..." "I only sow down a few dryland corners..." "I only seed wheat for terminated cover for my cotton..." Here are reasons why karnal bunt should be a concern, even for the above. If infected seed is planted then spores can lie dormant for at least 5 years. Some growers are starting to look at growing small grains as a means to reduce the number of acres they are trying to irrigate during the summer. If bad seed was planted as cover in 2001 and then the farmer decides to grow wheat down the road on that field, he could face infection problems. Karnal bunt can also be introduced through wheat planted just for conventional cover. Spores could still be spread to other fields through tillage tools or possible movement via other means. Bottom line -We don't know of karnal bunt in the South Plains. Infected seed is the most likely risk for the region. By all means, ensure your wheat is free from karnal bunt by beginning with a reputable seed dealer or other known source of seed. Ask where the seed came from, ask for a test (expensive), or on the other hand just simply don't plant seed that potentially came from an infected region (e.g., the Rolling Plains). CT
Update for NuSun oilseed pricing and changes in delivery points. Among the two markets for NuSun mid-oleic oilseed sunflower in Lubbock, Red River Commodities (800-763-9740 or 806-763-9747) expects to complete construction of their new bird food plant on North Loop 289 and begin production by October 1. Red River is in the market for NuSun and also any conventional oilseed sunflowers. Meanwhile, due to the lower than expected acres of NuSun in the South Plains, Southern Cotton Oil has announced that they will not crush NuSun as hoped in Lubbock. Any growers that signed contracts with SCO needs to call them for details on alternative delivery points. Southern Cotton Oil's sister company, Northern Sun, Goodland, KS (800-542-7333) has arranged for purchase and delivery of NuSun through Attebury Grain, Lubbock, (806-765-7223) or Southwestern Grain, Plainview (806-293-2643) (point of sale, no charge for delivery to Goodland, KS). Growers with NuSun may call Attebury Grain in Amarillo (806-335-1639) for pricing information, which is the same at both locations. Northern Sun also anticipates having a delivery point in the Muleshoe area. For current pricing information on South Plains delivery, NuSun growers should call Red River or Attebury Grain, Amarillo. Prices are changing daily, sometimes by quite a bit. As of Tuesday, August 21st, prices for August, September, and October-November delivery were in the range of $7.80, $7.25, and $6.90 per cwt., respectively. LDP has dropped to about $0.95 per cwt (compared to over $3.00 per cwt. in early April). Traditionally, the LDP rises during harvest and as cash prices decline. Growers can anticipate a small 2-for-1 premium on oil content over 40%, but dryland oilseed could face a slight penalty as oil content may be lower than 40% due to drought. My calculations suggest that for Attebury purchase, the approximate price delivered to Northern Sun in Goodland is about $1.75 per cwt. higher. Growers may be able to arrange transportation for less, and could probably receive a higher net. CT
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