Southwest Michigan field crop regional report – May 22, 2014
Rainfall early in the week brought highly variable precipitation totals in Southwest Michigan.
Rainfall was the heaviest in Allegan and northern Van Buren counties, where it had already been wet for substantial periods of time. A second round of thunderstorms brought rainfall to southern Berrien and Cass counties before it tracked off to the Southeast. The remainder of the region received rainfall, but no significant planting delays are anticipated. A quick look across the region’s Michigan State University Enviro-weather stations shows totals ranging from 0.3 inches in several locations to a high of 1.63 inches in Grand Junction, Michigan, in Van Buren County for an average of 0.57 inches.
Growing degree days (GDDs)
In South Central Michigan, precipitation totals were somewhat higher with an average of 0.88 inches since May 15. GDD totals base 50 for the near shoreline areas averaged 189 since May 1 and 191 for South Central Michigan. GDDs base 50 since March 1 are at 361. The period from May 22-27 usually accumulates 12.7 GDDs per day, and the period from May 28-June 3 averages 13.4 GDDs base 50. The region has average 691 GDDs base 41. Michigan State University Extensions’ guidelines for harvesting high quality alfalfa forage for dairy cattle are at 750 GDDs.
NOAA's 6-10 and 8-14 day outlooks have the region in the much above category in temperature, and in the above normal precipitation for both periods. With three to four days of anticipated dry weather, lighter ground areas may be able to be nearly finished with planting if the window holds.
Advanced commercial corn fields are at V2. Most early planted fields are at V1 or spike. Lots of corn across the region has yet to emerge. Planting is nearly complete in the southern two tiers of counties in the Southwest. Most early planted stands are beginning to look better. Some frost damage occurred as a result of the May 15 frosts, but damage looks to be light, especially to the West. Weeds are beginning to come on strong. Spraying windows have been relatively small due to windy conditions. Most early planted fields had little winter annual weeds or cover crops, so I expect few problems with either armyworms or cutworms on these fields. Later planted fields where green tissue existed during Mother’s Day weekend, May 10-11, or beyond should be scouted in about 10 days for these pests.
Seed corn planting is moving forward on schedule. Wet conditions have created some challenges, but so far most of the planting delays between male and female inbreds have gone off OK.
Early planted soybeans have emerged and look good for the most part. Relatively few fields have emerged yet compared to corn. There are no pest issues to date.
Wheat is in Feekes growth stage 7 and rapidly progressing towards Feekes stage 8. Most of the nitrogen has gone on and the fields are looking better all of the time. We did have a brief period where irrigation water might have been helpful to the developing crop on irrigated sands last week. As temperatures increase, monitor soil moisture conditions next week in areas that have missed the higher rainfall totals. There is limited leaf disease issues in the lower canopy in the fields I have walked, and a little bit of powdery mildew in just a couple of fields.
Alfalfa growth was spurred on by the warm temperatures a week ago or so and continues on a decent pace, considering the temperatures. With the heat in the forecast, we should reach the 750-GDD threshold for first cutting harvest in some areas within the week. Some early harvest has begun in the region.
Some fields have been treated for alfalfa weevil. There are two methods for determining treatment thresholds for this pest:
- Visual scouting. Before first cutting, sample 20 stems in five different locations of the field and look for larvae and damage. Threshold: before first cutting, 40 percent of stems damaged, plus live larvae present; after first cutting, 25 percent or more of new tips damaged, or six to eight larvae per square foot of regrowth.
- Stem-and-bucket method. Pick 10 stems randomly as you walk and place them upside down in a bucket. Shake vigorously to dislodge large larvae then pull apart the stem tips to find small larvae missed by shaking. Threshold: alfalfa less than 12 inches = one or more larvae per plant; 12- to 16-inch alfalfa = two to four larvae per plant; 16-plus alfalfa = consider cutting.
Of course, instead of treating, harvesting can be an option, especially if you can be ready to cut within three to four days.
There are lots of insecticide options for controlling this pest if you are over the treatment threshold. See MSU entomologist Chris DiFonzo's alfalfa pest management and insecticide recommendations.
With warm temperatures in forecast, we should see the beginning of snap bean planting this next week.
Other Michigan State University Extension field crop regional reports from this week: