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The Cropwalker - Volume 2 Issue 22

Always read and follow label directions.

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Crop Conditions

Winter wheat Earliest is flowering. Most fields are at least at flag leaf. Review of FHB timing. Once 75% of heads are emerged is day 0. The next 3 days, day +1 to day +3 are the optimum days to spray for FHB control. Prosaro or Caramba can be sprayed from day +1 to day +5. Corn – Planting is winding down. Agricorp has extended planting dates for two days. Probably 75-80% of the corn is planted. Some of the remaining acres will be switched to cover crops or soybeans or to corn with no crop insurance. Lots of corn emerging earliest at 5th leaf stage. Any field that has 17-18,000 plants per acre should be left. Once you get below 12,000 consider getting more plants in, presuming that seed in the ground will not emerge. Soybeans planting continues. Some of earlier planted acres are being replanted. Forages – first cut is harvested on many acres. Because of wet weather conditions consider spraying Priaxor on alfalfa. Best results are when Priaxor is sprayed 21 days before harvest. Consider spraying 7-10 days after first cut. New seedings are at the 1-3rd trifoliate in many fields. If you are going to spray Cobutox/Embutox do it now. Alfalfa is more tolerant to Cobutox/Embutox at earliest stages. Weeds are easier to kill when they are small.


Should I replant with Lower Soybean Populations?

Bottom line is if you have 90,000-100,000 healthy plants now, leave the stand. The table gives estimates of potential yield. The issue is that replanting (to get a higher population) you must factor in a later planting date. This year areas of some fields will have low populations. In most areas you should know how many seeds will emerge by the time the soil is dry enough to plant. If touching up areas, consider dropping 100,000-120,000 seeds/ac. If possible, use the original variety. You may kill some plants (up to 50%) with a drill if you are on 7” rows. (This is a summary of information from Pub 811 Table 2-13 which is in plants/ha.)

Table 1 - Expected yield by plant pop. by row width

Cleansweep Tips

Missed your pre-emerge application on soybeans? This is a common issue on years like this, but don’t miss your Cleansweep window as well! Label states up to 21 days after planting. Don’t wait 3 weeks. Target 10-15 days after planting for your first application. Ideally the annual grasses will be 1-3 leaf, with the broadleaves at the cotyledon to 2 leaf stage. Use 20 gallons of water, and don’t forget to add the 0.8 L/ac of 28% UAN. Do not add any additional Pursuit, it will not improve upon what’s already in the co-pack. A second cleanup application (in-crop) maybe required depending on weed spectrum and resistance.

Watch Temperature When Spraying

Crops break down herbicides in the first few hours after application. Try to avoid spraying when temperatures are above 28 o C or when there is a 25 o C swing in temperatures. If you have to spray during these times increasing water volume and decreasing any surfactant may reduce negative effects of herbicides. There are no known weather restrictions for spraying fungicides (you still need to hit the target).

Corn Post Emergent Spraying

Some products have definite stages to spray before. Typically, they are 1- 3 or 5-6 leaf stage. With current weather, later planted corn will go through growth stages faster in June than in May. Better to spray too early than too late.

Checking Fields with Emergence Issues – Too often someone checks a field and when someone else checks it there is a different population. If worried about emergence, use drainage flags and check every two days to see if % emergence changes. If you forget your drainage flags then draw a line in the dirt or pile stones at both ends of your area, usually 1/1,000th of an acre. For 30” rows measure 17’ 5”.

Apply Manure to Hay Fields – A 3-year forage stand removes about 900 lbs K20 and must be replaced. Dairy manure is high in K so this is a good place for manure in the summer months. There are added benefits to using manure as your fertilizer source over commercial fertilizer on hay. University of Wisconsin research shows that spreading manure on hay ground increases both quality and yield by 5.6% and 10%, respectively. This combined equates to 12% more milk per acre on average. Apply 3,000-4,000-gal manure after cutting before regrowth begins, as tire traffic on new growth will reduce yield. This rate should give about 90 lbs K. It is not recommended to apply manure to hay that will be used for baleage as it could cause improper fermentation.

Purple/Yellow/Red Corn – We have seen it before. A review: the most common contributor to the development of purple corn is the combination of bright, sunny days and cool nights (40°F to 50°F) when corn plants are in the V3 to V6 stages of development (3-6 leaf collar stages). This combination translates to a lot of photosynthate produced during the day, but low rates of photosynthate metabolism during the night. This results in high concentrations of sugary photosynthates in the leaves. Since the anthocyanin occurs in the form of a sugar-containing glucoside, the availability of high concentrations of sugar in the leaves (photosynthesis during bright, sunny days) encourages the different colour pigment formation. Hybrids with more anthocyanin-producing genes will purple more greatly than those with fewer “purpling” genes. In most cases, the purpling will slowly disappear as temperatures warm and the plants transition into the rapid growth phase (post-V6). (notes from Dr. Bob Neilson Purdue)

Winter Wheat – Late N/Post Anthesis

1.     If the flag leaf has emerged, and you still have to apply nitrogen to your wheat crop, I would recommend using a spinner with a product such as AmidaS, or Urea. This will minimize leaf burn compared to if you were using streamers and applying 28% UAN.

2.    You are growing hard red wheat, and want to apply post-anthesis (10 days after flowering)? Use a minimum of 10 gallons/ac of 28% UAN plus 10 gallons/ac Water. The 30 lbs of actual N/ac (10 gal./ac 28%) should bump protein levels by a minimum of 0.5 %. Last year in dry weather we saw a 1.5-2% gain. Do not apply during the heat of the day. This practice should not be used on Soft Red or Soft White classes of wheat.

Winter Wheat – T3 Application

Prognosis is for high Fusarium levels in wheat this year. A FHB fungicide application can reduce DON levels by 50%. A fungicide application at this time can increase yield by 7 bu/ac if 100 lbs/ac N was applied and 10 bu/ac if 135 lbs/ac N was applied. (Source: SMART Wheat Trials)

Wheat Flowering Time – Wheat head starts to flower from the center of the head. Then flowering and pollination occurs to the top and bottom of the head. Normally, flowering is over in 7 days. It is during this flowering period that you want to apply the FHB fungicide. Products of choice are Caramba and Prosaro. The strobis such as Quilt and Headline can increase DON levels. You should not apply strobis during pollination time. Because of field variability you have to weigh best timing with weather and availability of equipment. The preferred equipment is ground. Aerial application is less effective controlling Fusarium but still gives a yield boost.

What nozzle should I be using?

I quite frequently get this question when spraying post emergent herbicides. The real question is, what droplet size should I be using to hit my target? Start from point of contact on the plant, not the end of the spray boom. The label states what size of droplet you should be targeting. The chart below is a good starting point for optimal droplet size on some commonly used products. Then look at the spray chart to determine which nozzle is appropriate for the application. You could be off label by using the right tip, but the wrong pressure.

Table 2 - Optimal Droplet Size for Select Products

This chart is a common flat fan nozzle, make note of how differences in pressure can affect droplet size. Select a nozzle that will achieve target droplet size, water volume and ground speed.

Figure 1 - Teejet XRC Nozzle Chart

A really good resource to sorting the right nozzle is the Teejet Nozzle Selection Guide. It will help with getting the right product, but not necessarily the exact nozzle size for your application without a little math. Link to Teejet nozzle selection guide;

Nozzles | TeeJet® Technologies

Nozzles | TeeJet® Technologies

TeeJet spray tips and nozzles help improve plant health, increase crop yields, improve the efficiency of pest control, and increase profits.

"Farmers farm. Everybody else just plants crops. "

- Jonathan Zettler