Regional reports on Michigan field crops – June 23, 2011
MSU Extension educators’ pest and field crop updates for Michigan.
This week’s regional reports:
- Southwest Michigan – Bruce Mackellar
- West Central Michigan – Fred Springborn
- Central Michigan – Paul Gross
A significant push of warm air and heavy thunderstorms was the major weather story in the region this week. Rainfall totals ranged between 0.5 to over 5 inches from thunderstorms on Tuesday (June 21). Additional rainfall on Wednesday (June 22) added to the total precipitation. Cooler conditions following the passage of the cold front may help to reduce flooding injury and mortality on crops that are underwater in areas that received heavy rain. Wet conditions will interrupt sidedress operations in corn, but cooler temperatures may help to slow down the rapidly developing crop. Enjoy the soft conditions now. With the longer term forecast turning warmer and drier, our shallow rooted crops might be under moisture stress in the not so distant future.
A quick look around the region shows that we are at 744.7 GDD’s Base 50 since May 1. The average GDD accumulation Base 50 in the region for the next five days is 18.2 and the following five days is 21.2. We are rapidly stepping up the time when heat units accumulate in July and August. The 6-10 day and 8-14 day outlooks have southwest Michigan solidly in the above-normal temperature range.
Rainfall total from these storms ranged from 0.48 inches in Bainbridge to 2.32 inches in Cassopolis, with an average of 0.97 inches across the 12 MSU Enviro-weather stations in the southwest region. Some areas received considerably more, especially in Allegan and Ottawa Counties. The 6-10 day outlook has southwest Michigan in the below normal range and 8-14 day outlook has the southwest corn of the region in the normal precipitation, with much of the rest of the region and the stat in the below normal range.
Wheat is moving towards maturity. Head scab is visible in fields that were not treated with fungicides in some areas. Heavy rains driven by high winds caused lodging in some areas. Evaluate your fields for harvest timing and grain quality strategy.
Second cutting alfalfa is growing well. Potato leafhopper activity and numbers are on a significant upswing. While most of the fields have plant height on their side right now, it is important to continue to watch for signs of leafhopper feeding injury. Continue to monitor fields for alfalfa weevil larvae and potato leaf hoppers.
Early planted corn fields across the region are at the 8 leaf collar stage or more. The tallest plants I have seen are about chest high. This is an important stage for post emergence glyphosate applications. Most of the glyphosate labels restrict applications to corn above 8 visible leaf collars or 30 inches in height. Drop nozzles can be used with some glyphosate materials. Later planted corn is still in the 5 to 6 inch height range. We will begin western bean cutworm trapping in earnest over the next couple of weeks. Evapotranspiration rates will also rapidly be on the rise as corn enters the rapid elongation phase. Plant canopies quickly fill in between V8 and tasseling, creating much more demand for available soil water.
Soybeans are at R1 for the most part. Later planted soybeans are in the V1-2 growth stages. Herbicide application on soybeans continues to be a challenge in some areas, with larger weeds in some fields. We should add soybean aphids to the watch list for growers across the region. I was able to find a few soybean aphids on plants in St. Joseph County on Wednesday (June 22). Field crops entomologist Chris DiFonzo reported enough soybean aphids on a few fields on campus that they could find ants tending the colonies, a sign that they had been in the field for a while. Ants crawling on the surfaces of soybean plants are a good clue that soybean aphids may be present.
I have not seen anything more than just a few aphids per plant. Soybean aphids can reproduce rapidly, however, and winged aphids can be blown in from significant distances away, especially with all of the thunderstorm activities we have seen. Other insect pressure has been light so far. The next big insect pressure in soybeans should come in the form of Japanese beetles, which usually emerge in late June – early July in our region. I have not seen any emerged adults at this time. We have had some questions this week on adding micro-nutrients to the glyphosate tank to save a trip across the field. For an excellent discussion about glyphosate applications on corn and soybeans, including micronutrients and adjuvents, click here to review Dr. Mark Bernard’s (University of Nebraska, Lincoln) article on the subject.
Most areas received 2 to 3 inches of rainfall over the past 48 hours (June 21-22). Some areas received as much as 5 inches from this storm system. Flooding has returned to many fields, causing delays in pesticide applications and other field operations. High temperatures have been in the 70s to low 80s.
Corn growth stage ranges from V2 to V10. A few fields are showing the effects of the high winds with plants leaning and mild leaf tearing. This storm damage will likely have little long term effect on the still relatively young corn plants. Western bean cutworm traps are being put up this week.
Wheat is filling kernels. A few scattered fields have lodged in the recent storms.
Soybean growth ranges from unifoliate up to 3 trifoliates. We are starting to detect soybean aphid in several fields at very low levels.
Fields are saturated after 3 to 5 inches of rain on June 22-23. Many fields have standing water and the rain continues to fall. The warm weather has provided for very rapid emergence and growth of later planted crops. Many farmers are finding it a challenge to make herbicide and nitrogen applications due to wet soils and high wind speeds. The concern is the standing water will not recede fast enough and crops will be lost in the low lying areas. Western bean cutworm traps were set out last week and not moths have been caught.
The corn crop ranges from just emerging to V10. The warm temperatures are aiding crop growth and many of the early symptoms of yellowing and striping have disappeared. The reports of cutworm and armyworm problems have stopped. The challenge at this point is getting the sidedress nitrogen applications made with the saturated soils. Weed pressure in some fields is extreme and herbicide applications are needed. This is the year when farmers will need to scout fields on a regular basis to identify any crop problems early.
Soybean planting wrapped up late last week with quick emergence of the later planted fields. There is concern that with all the rains and saturated soils, seedling diseases will be an issue. Scout fields for crop problems. Weed populations in several fields are now competing with the crop. Weed sizes are bigger than normal, so adjust herbicide rates accordingly. There are some bean leaf beetles in fields.
The wheat crop is beginning to turn. The rains and high winds this week have caused some wheat to go down. The fields that have had high rates of manure and where nitrogen applications overlapped have more lodging. Fields with fungicide applications are clean of foliar diseases at this time.
Harvest of first cutting alfalfa is complete. The rains have been just like irrigation for the regrowth. After a very good first cutting, it appears second cutting will also be very good. Harvest of second cutting will begin next week. Scout fields for insects. Rains are keeping those trying to get grass hay dry from wrapping-up first cutting.
Oats and barley are beginning to head. The crops look good at this time.
Dry bean planting is nearly complete. Emergence has been rapid with adequate temperature and weather.