Chad Lee, Extension Agronomist, University of Kentucky
The Corn, Soybean and Tobacco Field Day is scheduled for August 9, 2012 at the University of Kentucky Research and Education Center in Princeton, KY. The morning program will begin at 7:30 am with registration and end at lunch. The lunch is sponsored by the Kentucky Corn Growers and the Kentucky Soybean Board.
The corn and soybean topics will all be discussed on the morning. Format of that program will be very similar to the wheat field days. Tobacco will have programs in the morning and afternoon.
Some of the topics to be discussed are corn row widths and yields, nitrogen management, and high yield soybean.
Wednesday, June 20, 2012
Friday, June 15, 2012
More Corn and Soybean Challenges in Fields
Chad Lee, Extension Agronomist, University of Kentucky
The images from field problems in Kentucky has been updated. Because the file was getting very large, you can access only the May 2012, June 2012 or the full version which includes wheat. If you access the full version, just be aware that it is 23.5 MB... and growing.
The most common symptom in corn is potassium (K) deficiency. In most cases, the K deficiency is the result of root restriction. Most of the root restriction is from compaction, whether it be sidewall or sub-surface. Areas of Kentucky had ample rain during corn planting and getting sidewall compaction would have been very easy to do. The general lack of rain now adds to the problem.
The compaction limits root growth, reducing the root interaction with nutrients. Water is needed for uptake of many nutrients, including compaction. The lack of water reduces the amount of K taken up by the plant. Either dry weather or compaction on their own can cause problem, but having both together causes even more troubles.
The most common symptom in corn is potassium (K) deficiency. In most cases, the K deficiency is the result of root restriction. Most of the root restriction is from compaction, whether it be sidewall or sub-surface. Areas of Kentucky had ample rain during corn planting and getting sidewall compaction would have been very easy to do. The general lack of rain now adds to the problem.
The compaction limits root growth, reducing the root interaction with nutrients. Water is needed for uptake of many nutrients, including compaction. The lack of water reduces the amount of K taken up by the plant. Either dry weather or compaction on their own can cause problem, but having both together causes even more troubles.
Thursday, June 14, 2012
Watch for Japanese beetle on “Silking” Corn.
Doug Johnson, Extension Entomologist
Japanese beetles have been emerging over the last couple of weeks. With the general rainfall we had last Monday (6/11/12) this emergence is likely to quicken. While this insect will feed on corn leaves, its’ only real importance is when feeding on emerging silks. This silk feeding can interfere with pollination resulting in incomplete kernel set. Figure 1.
These insects are metallic green beetles about ½ “ long. They have a row of white tufts on either side of the body below the bronze wing covers. The beetles will congregate (sometimes in very large numbers) on ear tips and feed on the silks, thus preventing proper pollination.
Normally, this insect is not a major pest of corn. However, in this year because of the mild winter and very warm spring the pest is emerging at an earlier date. Also, because of the dry soil conditions in the western part of the state, the emergence which is normally spread out in time, may occur over a much shorter period producing an unusually large number of beetles seemingly all at once.
Scout for this insect by examining several individual groups of 20 consecutive ears. Determine if the silks have been clipped to within 1/2” in length. Additionally, count the number of beetles per ear and average these numbers for the twenty ears per sample, then average all the samples taken in the field. Treatment may be necessary if silks have been clipped to ½” and there are three or more beetles per ear.
If pesticide application becomes necessary, pesticides useful for control of Japanese beetle can be found in ENT-16, Insecticide Recommendations for Corn-2012, which may be obtained from your County Extension Office or on line at:
http://pest.ca.uky.edu/EXT/Recs/welcomerecs.html
Photo: ©D. Johnson, Univ. KY
 |
| Japanese beetles feeding on corn silks. |
These insects are metallic green beetles about ½ “ long. They have a row of white tufts on either side of the body below the bronze wing covers. The beetles will congregate (sometimes in very large numbers) on ear tips and feed on the silks, thus preventing proper pollination.
Normally, this insect is not a major pest of corn. However, in this year because of the mild winter and very warm spring the pest is emerging at an earlier date. Also, because of the dry soil conditions in the western part of the state, the emergence which is normally spread out in time, may occur over a much shorter period producing an unusually large number of beetles seemingly all at once.
Scout for this insect by examining several individual groups of 20 consecutive ears. Determine if the silks have been clipped to within 1/2” in length. Additionally, count the number of beetles per ear and average these numbers for the twenty ears per sample, then average all the samples taken in the field. Treatment may be necessary if silks have been clipped to ½” and there are three or more beetles per ear.
If pesticide application becomes necessary, pesticides useful for control of Japanese beetle can be found in ENT-16, Insecticide Recommendations for Corn-2012, which may be obtained from your County Extension Office or on line at:
http://pest.ca.uky.edu/EXT/Recs/welcomerecs.html
Photo: ©D. Johnson, Univ. KY
Tuesday, June 12, 2012
Southwestern Corn borer Flights on the Rise
Doug Johnson, Extension Entomologist
Adult flight of southwestern corn borer (SWCB) is on the rise and has many producers asking questions. This insect can be problematic in Kentucky’s major corn growing region, is more problematic in the western half of the state and is particularly important in the Purchase Area. The UK-IPM program runs pheromone baited traps to monitor this pest in Lexington and Princeton, KY experiment farms and cooperates with Mr. Cam Kenimer, the Agriculture and Natural Resources agent in Fulton County, who monitors SWCB traps in his county. See:
http://www.uky.edu/Ag/IPMPrinceton/counts/swcb/swcbgraph.htm and
http://ces.ca.uky.edu/fulton/InsectTraps
Current Flight Status: This pest is rare in the eastern half of the state and no moths have been captured in the Lexington trap this year. In Princeton, moths are being captured and these captures are increasingly greater than the rolling five-year average. Thus far, the Fulton county trap has captured the largest numbers and, like Princeton, the captures are increasing (at this writing 75 moths per week).
This increase in captures has alarmed some individuals. Nevertheless, the capture rates thus far are nowhere near as large as the historic captures of the previous decade. See:
http://www.uky.edu/Ag/IPM/trapdata/trapdata.htm
Before the widespread use of corn products containing “B.t. corn borer traits”, the peak weekly captures were much greater. Consider the current 75 moths per week in light of the historic five- year average peak for 1999-2003 which exceeded 350 moths per week. In some years peak captures were in excess of 800 moths per week and it was not unknown to capture more than 1000 moths per week!
With a few local exceptions it is unlikely that there will be widespread damage to corn from this pest. Nonetheless, infestation rates in a specific field cannot be predicted by captures in distant traps. One must scout those fields to know the pest level.
Field corn products which contain “corn borer B.t. traits” will be largely protected from this pest. However, field corn refuges, sweet, pop and other food grade corns that do not contain “corn borer B.t traits” should be scouted for the presence of this pest.
One should scout for SWCB from June through August. There are at least two and possibly three generations per season. Monitor fields in June for “shot hole” feeding to whorl leaves. If damage is noted while walking through the field, examine 20 consecutive plants for each of several locations and record the number of plants that are damaged. If “shot hole” damage is recorded for 35% of the plants sampled, an insecticidal control is warranted. This is the most important time to treat as the second generation is very difficult to detect and control. If insecticidal control is warranted, you may find a list of approved products in ENT- 16, Insecticide Recommendations for Corn. This publication is available from your County Extension office or on the web at:
http://pest.ca.uky.edu/EXT/Recs/welcomerecs.html
Remember it is not the moths (Figure 1.) but ther the larvae aka caterpillars or worms (Figure 2.) that cause the destruction. Spraying when moth flight peaks is not really doing you any good. You need to wait until the larvae begin to appear. Using May 31 as a starting point (the peak of the current moth flight) a 50oF degree day model predicts that SWCB caterpillars should be showing up just abut now!
In addition, you must treat while the larvae are still active in the whorl. Once they are in the stalk, foliar application will not provide control.
For more information on the southwestern corn borer see: Entfact-108, Southwestern Corn Borer, available at your county extension office or on line at:
http://www.ca.uky.edu/entomology/entfacts/ef108.asp
Photos: R. Bessin, Univ. KY.
Adult flight of southwestern corn borer (SWCB) is on the rise and has many producers asking questions. This insect can be problematic in Kentucky’s major corn growing region, is more problematic in the western half of the state and is particularly important in the Purchase Area. The UK-IPM program runs pheromone baited traps to monitor this pest in Lexington and Princeton, KY experiment farms and cooperates with Mr. Cam Kenimer, the Agriculture and Natural Resources agent in Fulton County, who monitors SWCB traps in his county. See:
http://www.uky.edu/Ag/IPMPrinceton/counts/swcb/swcbgraph.htm and
http://ces.ca.uky.edu/fulton/InsectTraps
Current Flight Status: This pest is rare in the eastern half of the state and no moths have been captured in the Lexington trap this year. In Princeton, moths are being captured and these captures are increasingly greater than the rolling five-year average. Thus far, the Fulton county trap has captured the largest numbers and, like Princeton, the captures are increasing (at this writing 75 moths per week).
This increase in captures has alarmed some individuals. Nevertheless, the capture rates thus far are nowhere near as large as the historic captures of the previous decade. See:
http://www.uky.edu/Ag/IPM/trapdata/trapdata.htm
Before the widespread use of corn products containing “B.t. corn borer traits”, the peak weekly captures were much greater. Consider the current 75 moths per week in light of the historic five- year average peak for 1999-2003 which exceeded 350 moths per week. In some years peak captures were in excess of 800 moths per week and it was not unknown to capture more than 1000 moths per week!
With a few local exceptions it is unlikely that there will be widespread damage to corn from this pest. Nonetheless, infestation rates in a specific field cannot be predicted by captures in distant traps. One must scout those fields to know the pest level.
Field corn products which contain “corn borer B.t. traits” will be largely protected from this pest. However, field corn refuges, sweet, pop and other food grade corns that do not contain “corn borer B.t traits” should be scouted for the presence of this pest.
One should scout for SWCB from June through August. There are at least two and possibly three generations per season. Monitor fields in June for “shot hole” feeding to whorl leaves. If damage is noted while walking through the field, examine 20 consecutive plants for each of several locations and record the number of plants that are damaged. If “shot hole” damage is recorded for 35% of the plants sampled, an insecticidal control is warranted. This is the most important time to treat as the second generation is very difficult to detect and control. If insecticidal control is warranted, you may find a list of approved products in ENT- 16, Insecticide Recommendations for Corn. This publication is available from your County Extension office or on the web at:
http://pest.ca.uky.edu/EXT/Recs/welcomerecs.html
 |
| Figure 2. Southwestern corn borer larva (summer phase). |
 |
| Figure 1. Southwestern cornborer moth (adult), |
Remember it is not the moths (Figure 1.) but ther the larvae aka caterpillars or worms (Figure 2.) that cause the destruction. Spraying when moth flight peaks is not really doing you any good. You need to wait until the larvae begin to appear. Using May 31 as a starting point (the peak of the current moth flight) a 50oF degree day model predicts that SWCB caterpillars should be showing up just abut now!
In addition, you must treat while the larvae are still active in the whorl. Once they are in the stalk, foliar application will not provide control.
For more information on the southwestern corn borer see: Entfact-108, Southwestern Corn Borer, available at your county extension office or on line at:
http://www.ca.uky.edu/entomology/entfacts/ef108.asp
Photos: R. Bessin, Univ. KY.
White Grub Damage Evident on Corn.
Doug Johnson, Extension Entomologist
Early white grub damage typically appears as stunted, wilted, discolored, or dead seedlings and/or as gaps in rows where plants fail to emerge. White grubs prune roots and can feed on the mesocotyl causing plant death. Obviously we are far past this early damage stage. In larger corn, grub feeding simply prunes the roots resulting in the reduced ability to move water and thus nutrients. The plants simply have an unthrifty look.
While there are some soil insecticides labeled for grub control, their control is somewhat erratic. These products must be applied before or at planting. No insecticides are recommended for rescue treatments. Even if soil applied rescues were available, we would likely need some rainfall to move the insecticide into the soil, especially in no-till. If we got the rain needed for that, we would have the rain we need for vigorous growth in the corn crop; which would likely outgrow the problem.
Consequently, even though one might be looking for a pesticide remedy for this problem, what we really need is rain. In the presence of rain the problem is likely to go away. In the absence of rain…… well the damage just will not matter.
 |
| White grubs; photo courtesy of Iowa State University. |
Questions concerning corn root pruning by white grubs have surfaced across the state. A number of Ag. & Natural Resources agents have noticed typical damage and found white grubs in place, along with typically pruned roots. Certainly, given the drought status of most of our corn production area, it is within reason to believe that these grubs are placing an unusual stress on an already stressed crop.
Early white grub damage typically appears as stunted, wilted, discolored, or dead seedlings and/or as gaps in rows where plants fail to emerge. White grubs prune roots and can feed on the mesocotyl causing plant death. Obviously we are far past this early damage stage. In larger corn, grub feeding simply prunes the roots resulting in the reduced ability to move water and thus nutrients. The plants simply have an unthrifty look.
While there are some soil insecticides labeled for grub control, their control is somewhat erratic. These products must be applied before or at planting. No insecticides are recommended for rescue treatments. Even if soil applied rescues were available, we would likely need some rainfall to move the insecticide into the soil, especially in no-till. If we got the rain needed for that, we would have the rain we need for vigorous growth in the corn crop; which would likely outgrow the problem.
Consequently, even though one might be looking for a pesticide remedy for this problem, what we really need is rain. In the presence of rain the problem is likely to go away. In the absence of rain…… well the damage just will not matter.
Monday, June 11, 2012
Field Challenges around Kentucky
Chad Lee, Extension Agronomist, University of Kentucky
There have been a lot of field challenges around the Commonwealth this season. Each week, I have been trying to update a set of images with problems and what we think the answers are. I have been circulating this with our County Extension Agents and they think we should share this with everyone. If we are seeing these problems, you may be as well.
Just keep in mind, that these images are our best ideas about what is wrong in the fields. If you have suggestions or ideas, please pass those along to me. Thanks.
Click here to access the pdf. I plan to update it about each week.
Just keep in mind, that these images are our best ideas about what is wrong in the fields. If you have suggestions or ideas, please pass those along to me. Thanks.
Click here to access the pdf. I plan to update it about each week.
Wheat Harvest and the Wheat Yield Contest
Chad Lee, Extension Agronomist, University of Kentucky
Wheat harvest is underway in Kentucky and that means the 2012 Wheat Yield Contest is underway as well. The timing is early, by a couple weeks in some areas of the Commonwealth. That early timing be free up some time to enter the contest. To enter the contest, the field must be in Kentucky. At least 3 acres must be harvested for the contest. That 3 acres must be in one block and preferably with square sides.
Any County Extension Agent is eligible to serve as a judge for the contest. If a County Extension Agent is not available, then another person involved in agriculture (such as an adult ag educator, FFA instructor, NRCS official, etc.) may supervise the yield entry, so long as that person is not a family member and/or involved financially with the contestant.
Overall, the wheat plants are shorter this year. Many farmers are concerned about that. Jim Herbek and I blame the weather. The warmer season encouraged rapid development early, but not plant height. Those shorter heights probably will not affect final yields. The freeze damage in some areas did much more damage.
Wheat harvest is underway in Kentucky and that means the 2012 Wheat Yield Contest is underway as well. The timing is early, by a couple weeks in some areas of the Commonwealth. That early timing be free up some time to enter the contest. To enter the contest, the field must be in Kentucky. At least 3 acres must be harvested for the contest. That 3 acres must be in one block and preferably with square sides.
Any County Extension Agent is eligible to serve as a judge for the contest. If a County Extension Agent is not available, then another person involved in agriculture (such as an adult ag educator, FFA instructor, NRCS official, etc.) may supervise the yield entry, so long as that person is not a family member and/or involved financially with the contestant.
Overall, the wheat plants are shorter this year. Many farmers are concerned about that. Jim Herbek and I blame the weather. The warmer season encouraged rapid development early, but not plant height. Those shorter heights probably will not affect final yields. The freeze damage in some areas did much more damage.
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