Mississippi County
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September 15, 2006
Wheat Management
Wheat production information is available on the county agriculture web page under variety performance trials. The 2006 University of Missouri Crop Performance books are available in the office. When selecting a variety consider yield potential, test weight, disease and insect package, heading date and maturity date.
Consider the quality of the wheat seed you select. If you plan to use saved seed be sure it is properly cleaned. Cleaning the seed will remove small and/or shrunken kernels, which may be infected by seed-borne pathogens. You should use a fungicide seed treatment. It is also recommended to have a germination test done. Knowing the germination rate will allow for accurate seeding rates. Typically, wheat with a germination rate below 80% should be avoided. Seed quality also includes seed size based on thousand kernel weight (TKW). If possible select a seed with a TKW of 30 grams or higher because these seeds tend to have increased fall tiller number and seedling vigor.
Wheat does not tolerate wet feet, therefore select well drained fields and improve drainage in wet spots. Applying 15-25 lbs of nitrogen along with P and K following corn, grain sorghum or rice can improve crop health and root system. Phosphorus is essential for good fall and early spring growth. Target soil P level is 45 lb P/Acre. If you are at this level then crop removal rate amount or maintenance amounts can be applied. If unsure of your soil nutrient levels consider having your soil tested.
Optimum planting date can be a challenge and is dictated by weather and harvest of previous crop. With this in mind, The University of Kentucky recommends a planting date period of October 10 through October 30 for Kentucky. The University of Missouri’s optimal planting date is based on Hessian fly free date which is October 14. This date should be considered a target date for planting. In SEMO, actually being fly free around this date is questionable. If you have experienced Hessian fly damage in the past in a particular area of the county then plan on planting a tolerant or resistant variety. Varieties claiming resistance are few and far between. Contact your seed dealer for more information. In general, wheat planted prior to October is at increased risk of yield loss associated with aphid feeding, barley yellow dwarf virus as well as excessive fall growth which increases the risk of spring freeze injury. Another date to consider is the average first frost which for Mississippi County is approximately October 30. Although wheat will germinate in soil temperatures as low as 40 degrees, planting later than November 1 increases the risk of poor fall tiller development, winter injury, and heaving.
An optimal final fall stand should be approximately 35 plants per square foot. To obtain an optimal stand, base seeding rate on seeds per acre, this should be from 1.3 to 1.5 million seeds per acre. Ideal seed placement is between 1 and 1.5 inches deep when soil moisture is adequate.
Once wheat is up, plan on checking weekly for aphid levels and grass emergence. Aphid action thresholds are very low in the fall: 3 to 5 per foot of row on average. Fall is also the ideal time to control cheat and/or ryegrass. Know which one you have since different products work on these weeds.
Soybean Management
Soybean Rust
Yes, SEMO growers have been fortunate once again. The 2006 Sentinel scouting program worked well. The plots were scouted weekly and leaves were sent to a lab for analysis. Although we have been fortunate that weather in the South and Southwest has not been favorable for epidemic levels of spores to build up, please do not become complacent as we enter 2007. This disease has the potential for large yield loss if gone unchecked. Check the web for more info: http://www.sbrusa.net/ .
Soybean Insects
2006 will be remembered by many as the year of the worm. Corn earworm numbers were at levels I have not seen before. One thing many growers experienced this season is that fungicide + insecticide timing doesn’t always line up perfect. This gets back to scouting. The convenience of 2 birds-one stone concept is great and many times will pay off. However, if you can not find any insects at R3 you may consider holding off until they do come in.
Soybeans 2007
If you have sand fields, consider a root knot tolerant variety. University of Missouri Delta Center screens several varieties in Mississippi County each year. The list of soybean varieties sent to me is available on the county soybean web page. Hard copies are available in the office. If you don’t know if you have root knot, now is the time to sample your fields.
In 2006 areas between the river and Hwy 77 South (Alfalfa Center/Wyatt) experienced high levels of Japanese beetles. Those who farm in the Japanese beetle areas may be concerned about grub damage next season. Grubs are known to be an economic root feeding pest in corn. The grubs will prune soybean roots; however, most research indicates that it is typically not at an economical level. The biggest economic threat to soybeans is defoliation by adult beetles. With that in mind, entomologists still recommend using an insecticide seed treatment to help keep adult beetles in check and help with grub numbers when rotating back to corn. Purdue and Illinois have good summaries on grubs at the following websites: http://www.entm.purdue.edu/fieldcropsipm/insects/soybeanwhitegrubs.cfm; http://www.ipm.uiuc.edu/fieldcrops/insects/japanese_beetles/
Corn Management
Corn in the Sand
Corn this season was hit pretty hard in some of the sand regions of the county. Yes some areas were following potatoes and other areas had never had potatoes. The primary pests that I found to be common in many of the fields sampled were high levels of stubby root and root knot nematode. In all samples sent off the levels were 2 to 3 times threshold. Root knot nematode and stubby root are different from the cyst nematode associated with soybeans. These nematodes will feed on any crop root one exception being wheat. Therefore two years of corn will not cause populations to decrease like a cyst population would. The stubby nematode’s preferred host is corn or other grasses. The root knot just prefers a root. If you experienced some damage this year and did not get your field tested this spring then it might be some guessing but very likely you had some nematode damage. The problem with these nematodes and corn is the lack of tolerant varieties. Rotating to wheat followed by fallow system would decrease the pressure. Resistant soybeans would help. Fumigation would help but cost prohibitive for field crops. Terbufos (Counter by BASF) is a nematicide labeled for corn. Terbufos is a granular and will need additional boxes plus with Terbufos you can not apply ALS herbicides. Some growers have asked about carbofuran in furrow. Due to the age of the product and high toxicity level, there is no recent data available on the efficacy of this product on corn nematodes. The product label does not mention nematodes on the corn section. In general, having roots available during the late spring and summer season will allow feeding and reproducing of root knot and/or stubby root nematodes making it difficult to completely eliminate the threat or break the cycle.
Corn close to the River
In 2006 areas between the river and Hwy 77 South (Alfalfa Center/Wyatt) experienced high levels of Japanese beetles. These beetles are known to lay eggs in grass sod, corn and soybeans. Grub feeding on corn roots can cause yield loss. It is difficult to predict if a field will have grub damage. Again refer to the two articles from Purdue and Illinois above.
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University of Missouri Extension Mississippi County mississippico@missouri.edu Updated 05/24/04 |
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