Crop & Pest Report - All
Crop Management Field School
NDSU Extension Service’s annual crop management field school will be offered Thursday, June 18, from 9 a.m. to 3:30 p.m. at the Carrington Research Extension Center (CREC). The school will provide hands-on training on crop and weed management using field research and demonstration plots. Field sessions include weed identification, herbicide site-of-action, corn post-emergence nitrogen application; and soybean production management. For further details and preregistration information, go to www.ag.ndsu.edu/CarringtonREC or contact the CREC at (701) 652-2951. Preregistration (completed form and $75) is required by June 15 ($100 after June 15). CCAs participating in the event will receive five continuing education credits.
Area Extension Specialist/Cropping Systems
NDSU Carrington Research Extension Center
The region’s NDAWN stations indicate rain received during May 1-19 ranged from 3.8 inches (Harvey) to 6.0 inches (Marion), with reports indicating totals near 10 inches. Recent rains (May 16-18) ranged from 0.7-2.6 inches with several inches of snow. The rain (and snow) cooled soils – the region’s average temperatures at the 4-inch depth on bare ground (NDAWN) on May 18 ranged from 36-46 degrees. Also, May 19 had the lowest minimum air temperatures, ranging from 22-32 degrees. Crops with growing points below ground (small grain, corn and field pea) are expected to tolerate the cool soil temperatures, although some foliage may be damaged from the low air temperatures, especially with corn. Emerged soybean was at the greatest risk for plant death. With all crops, inspection for regrowth during this weekend will indicate plant response to the cold environment.
The weather forecast indicates that planting should resume the late this week. A small percentage of corn acres are yet to be planted while soybean will be the primary focus, with about 25% of the acres currently planted. Dry bean and sunflower planting will also commence when soil conditions are fit.
Area Extension Specialist/Cropping Systems
NDSU Carrington Research Extension Center
It was a quiet week for farm activity but a big week of precipitation in the form of rain, snow, and freezing rain. Rain accumulations for the week are between 1.2” and 3.75”. Benson County has reports over 5 inches of rainfall in last 10 days in isolated areas.
We remain cold. Minimums hovered around 28°F in the northern tier counties. By the end of week, we should have a clearer picture if any frost damage occurred. Emerging soybeans and sugarbeets are the highest risk crops to evaluate. Canola can handle down to 24°F. Cotyledon stage canola is less frost tolerant than older canola. Cotyledons can be frost-nipped and the plant still can survive. Growers should scout for an alive growing point, which will have developing leaves expanding. Allow 4 to 10 days after frost before making a final determination.
Area Extension Specialist/Agronomy
Rainfall based on NDAWN data indicates rainfall totals ranging from 1.32” to 2.31” during the past week in Garrison and Minot, respectively. Individual producer accounts have reported over 3” of rainfall in isolated areas. In addition, Minot received 1.5” of snowfall on May 18. Minimum freezing temperatures in the region ranged from 27 to 31 degrees in Bowbells and Minot, respectively. Duration of freezing temperatures ranged from 2 to 8 hours. Rugby had freezing temperatures 4 days over the last week. Corn GDD based on a May 1 planting in the region are an average of 80, corn planted before this date may be emerged. Damage from freezing temperatures on emerged crops is of concern. Most producers are concerned about emerged flax and canola. Very few soybean fields in the region have emerged.
Area Extension Specialist/Cropping Systems
Keep Stored Grain Cool and Dry During Summer
Stored grain needs to be cool and dry during the summer. Keeping stored grain cool helps reduce insect infestations and mold growth. Cold or cool grain has been safely stored through the summer for many years.
That means grain should not be warmed to average outdoor air temperatures during the summer. The goal is to keep the grain as close to 40 degrees F as possible in northern regions of the U.S. and as close to 50 degrees F as possible in southern regions. Grain at the top of the bin and along the walls will be warmer than that, but the goal should be to keep the bulk of the grain cool.
One reason for keeping grain cool is that insect infestations and mold growth are more likely at warmer temperatures. The optimum grain temperature for insect activity is approximately 70 to 90 degrees F. Reducing grain temperatures below 70 degrees F will lessen insect reproduction and activity. Also, warming the grain using aeration may increase the moisture content of the grain slightly. Typically, the increase will be less than 0.50 percentage point.
Despite some people’s belief that condensation will occur, particularly near the bin wall, if the grain is not warmed to near average outdoor air temperatures; however, that is not the case. Condensation forms on cool or cold surfaces when warm, moist air comes in contact with the cool surface. An example of this is condensation on a glass or container of cold liquid.
In the case of stored grain, warm, outdoor temperatures heat the bin wall during spring and summer, so conditions for condensation on the interior of the bin wall will not exist. The bin wall is warmer than the grain and the air in the stored grain.
There also has been concern that moisture will move from the warm grain near the bin wall into the cooler grain away from the bin wall. However, when 16 bins of grain were monitored through a summer, no statistically valid change in grain moisture content occurred within 4 feet of the bin wall.
Many grain storage problems that have been blamed on leaving grain cold during the spring and summer actually are the result of condensation during the fall and winter. Condensation will form on the interior of the grain bin wall when warm grain is placed into a bin with a wall that is being kept cool by cold outdoor temperatures. Reports of grain sticking to the bin wall and possibly deteriorating likely are due to condensation in the fall causing the grain to increase in moisture content and then deteriorate during the spring and summer due to mold growth occurring when temperatures grow warmer.
Aeration fans should be covered to prevent wind and a natural chimney effect from warming the grain. Wind blowing into uncovered fans or ducts will move air through the grain in a way that is similar to operating an aeration fan.
One problem during the summer is that a galvanized bin roof absorbs large amounts of solar energy, heating the air above the grain. Convection currents in the grain flow up along the bin wall and down into the grain near the top middle of the bin, drawing this heated air into the grain. Ventilating the space between the grain and the bin roof can reduce the amount that the grain near the top of the bin is warmed.
Natural ventilation to cool this space can occur if the bin has openings near the eave and peak; these openings work in like the vents in an attic of a building. The heated air rises and exits near the peak, drawing in cooler air near the eave. This natural ventilation will not occur unless the bin has adequate openings at the eave and peak. Roof exhaust fans also can be used to draw the heated air out of the bin if it has openings to allow air into the area above the grain.
Cool the grain near the top of the bin by operating the aeration fan about every three weeks to reduce the potential for insect infestations during the summer. Using positive pressure aeration to push air up through the grain enables the cool grain in the bottom of the bin to cool the air, which then cools the grain near the top of the bin.
Only run the fan long enough to cool the grain near the top surface. That may require running the fan for a few hours during a cool, dry morning for a couple of days. Running the fan more than necessary will warm more grain at the bottom of the bin, increasing the potential for storage problems.
If the air dew point is warmer than the grain temperature or if the air relative humidity is high, some moisture will condense onto the grain during fan operation. Condensing moisture will release heat that will warm the air slightly, reducing the effectiveness of the aeration and increasing the amount of warming occurring in the grain at the bottom of the bin. Therefore, selecting mornings when the air is cool and dry is important.
Check the grain moisture content to assure the grain is dry enough for storage at summer temperatures. The recommended long-term grain storage moisture contents are about 13.5 percent for wheat, 12 percent for barley, 13.5 percent for corn, 11 percent for soybeans, 13 percent for grain sorghum, 8 percent for oil sunflowers and 10 percent for confectionary sunflowers.
Also measure the stored grain temperature at several locations near the top surface, along the walls and several feet into the grain. Temperature sensors are an excellent tool when monitoring stored grain, but remember that they only measure the temperature of the grain next to the sensor. Because grain is a good insulator, the grain temperature may be much different just a few feet from the sensor. Record the measured temperatures. Increasing grain temperature may be an indicator of an insect infestation or mold growth.
Insect infestation and mold growth occur rapidly at summer temperatures, so stored grain should be checked every two weeks. An insect infestation can go from only a few insects to a major infestation in less than a month. Using insect traps or placing grain samples on white material helps you look for insects.
Weed Control in Dry Beans
The following is a question from a consultant in NE. The answer can apply to dry bean growers in ND.
I am a crop consultant in Nebraska and was wondering if you have a weed control program that you would recommend for us to use in our dry edible fields this year. Our main problem weed is waterhemp. Our soils are light sandy and last year we applied 3 pts of Eptam + 1 pt of Dual PPI, followed by 2 pts of Prowl preemergence. About a month later we applied 4 oz of Raptor + 11 oz of Basagran + nonionic surfactant 0.25% v/v and 1.41 lbs AMS per 100 gallons. Four days later we applied 0.5 pts of Reflex with 0.25 % NIS and 1.41 lbs AMS per 100 gallons. This program was successful where we had a light water hemp infestation. However it was a great failure in the heavily infested fields. We did cultivate sometime after the Reflex application. If you don’t mind sharing with me what is the standard practice at your research station I would love to know what you use. I am sure you are thinking why doesn’t this guy ask the Nebraska weed science people. We have talked to them before but they do not have waterhemp in the dry edible growing areas of Nebraska. Thank you for your help.
Answer: Below are some factors to consider with herbicides used:
1. Eptam has about 3 weeks effective weed control then is broken down rapidly.
2. Dual has about 4 weeks effective weed control then is broken down rapidly.
3. Prowl is mostly non-soluble in water and requires rain or irrigation to move into the soil when weed seeds germinate. Prowl has several weeks of activity after activation.
4. Most all waterhemp is ALS resistant so Raptor would be ineffective. You may know if it is susceptible but I would doubt it.
5. Rates of Basagran and Reflex used are too low.
6. Nonionic surfactant (NIS) is the least effective adjuvant with the herbicides used
7. The rate if AMS was too low.
8. All POST herbicides should be applied to waterhemp less than 2 inches tall for greatest control.
Consider these options:
PPI Eptam at 3.5 pt + Sonalan at 2 pt/A or the highest rate allowed for soil type.
Apply Spartan Elite PRE at rates labeled for your soil type. Spartan Elite contains sulfentrazone (Authority or Spartan) + Dual. I am not sure if Spartan Elite or Spartan Charge is labeled in NE because of crop injury but you can check. Spartan Elite has shown synergistic weed control in NDSU research. Sulfentrazone give 8-10 weeks residual control. PRE herbicides require incorporation with water.
If all herbicides are incorporated sufficiently this program should provide excellent weed control through canopy. If waterhemp emerges apply the following herbicides before waterhemp plants reach 1.5 inches tall:
Apply Basagran at 16 fl oz + Reflex at 4 fl oz/A + methylated seed oil (MSO adjuvant at 1 to 1.5 pt/A + AMS at 8.5 lbs/100 gal
If needed apply the same treatment again after 10 days. No more than 0.75 pt/A can be applied in a growing season in ND so you must check to see your total use limit and adjust rates accordingly and apply consistent with the label.
At NDSU we developed a program called the NDSU Dry bean tank-mix where 4 to 5 herbicides are applied together at reduced rates with MSO adjuvant. Some forms of it are used extensively. It was developed to control a wide range of weeds but in this case with your pivot weed being waterhemp we can adapt it for that weed. For example since waterhemp is resistant to ALS herbicides then Raptor can be eliminated unless you have other weeds that Raptor will help control. Refer to page 33 in the following file for the Dry bean tankmix listing:
Sequential POST applications are very important in dry bean weed control but must be done to SMALL weeds if it is to work. Refer to paragraph E3 and E4 on page 81 in the following file for information on Basagran and the effect of MSO adjuvant and on Reflex:
Also refer to paragraph F5 and F6 on page 83 in the same file listed above for more information on the NDSU Dry bean tank-mix.
MSO adjuvant is the most effective adjuvant for Basagran, Raptor, Reflex and many other herbicides. It high effectiveness may also cause some level of burn to dry beans leaves. Usually it temporary and the beans grow out of it. You will have to make the choice if you or your growers are willing to accept some potential crop injury from use of a very effective adjuvant. You can use an NIS with little or no crop injury but poor weed control or use an MSO with some potential dry bean injury but with the greatest weed control.
Extension Weed Specialist
Conversion of Dry to Wet Metribuzin
Question: I was wondering if you could help me clarify some questions that we have been getting from crop consultants and retailers lately. There is a trend of growers wanting to use liquid metribuzin instead of dry formulations due to ease of handling and sprayer cleanout issues. I have seen a lot of confusion in the field about what the conversion of dry formulations to the liquid equivalent is.
We contacted one of the technical service representatives for the manufactures of liquid metribuzin and were told to multiply the ounces of desired dry metribuzin by 1.58 to yield the ounces of liquid desired. Can you confirm that this conversion is accurate, it would help us let retailers and growers make an informed buying decision.
Answer: Thanks for sending. This would be an excellent problem for our undergraduates to use in their weed science courses. I think everyone is right if calculations are done correctly. It is most important to compare apples to apples and use active ingredient (ai) rates for both DF and 4L metribuzin formulations.
4 oz 75DF = 0.25 lb 75DF = 0.188 lb ai = 3 oz ai.
I was not aware the liquid formulations are 3.8 instead of 4 lb/gal. If so then:
3 oz ai of a 3.8 lb ai/gal metribuzin = 6.32 fl oz Metribuzin 4L
The conversion factor of 1.58 will work only when using oz of product not lbs. the calculation below is correct:
4 oz 75DF x 1.58 = 6.32 DL
In the weed guide we show metribuzin rates as lb 75DF/A. If incorrectly using 0.25 lb 75DF then the calculation will yield an incorrect number:
0.25 lb 75DF x 1.58 = ~0.4 fl oz 4L
Extension Weed Specialist
Control of Cover Crops
Question: I am wondering if you have done any work on residual control of turnips and radish planted as a cover crop. We had several areas planted last fall and with the dry weather they did not germinate. I am wondering what by best option for residual control in soybeans will be. I am thinking Authority Assist.
Answer: Turnips and radish are in the Brassica family which is the same family as wild mustard and canola. ALS herbicides are very effective as others listed in the weed guide. Look at ratings for wild mustard in the weed guide.
Extension Weed Specialist
Rivers to Nowhere
Now is a good time before bustling back to the field to drive around the fields and look, and take pictures and make notes of ditches that go nowhere. These are the long, thin lakes at the edges of many fields all across eastern North Dakota. Ditches were originally artifacts of building up the roadway, with I think little thought to actual drainage. Things are different now, and if there are some dusty township drainage district minutes from long ago, it is time to think about reviving them. Most interesting are the feverishly pumping tile drains going into the ditch, that goes nowhere and probably is recycled back underground into the field to be pumped into the ditch and so on and so on….
Where to start? Think about where the stream is. Maybe the land is so landlocked that some thought has to be given to eventually building a man-made wetland in part of a field just to hold the water. But let’s assume that looking over the landscape the general slope of the land goes towards a stream a few miles down the road. You look at the ditch. The culvert is half clogged with dirt and debris (it’s not soil in a culvert). Clean it out. The ditch has blown half full of soil from years of tillage. It’s time to dredge it out and put it back in the field, and reseed the ditch. Make sure it’s graded so it goes somewhere. Visit with neighbors and see about grading the rest of the ditch line so that when the water leaves your farm it doesn’t pond their farm and instead goes onward into the stream. And don’t farm the ditch!
Tiling is Step One. Making sure the water can go somewhere is Step Two (actually it was Step One, but somehow it was skipped in 1920).
NDSU Extension Soil Specialist