August 29, 2007
In this issue
§ Update on European corn borers and corn earworms
§ Status of aster leafhoppers and aster yellows
§ Third edition of Managing Cover Crops Profitably released
§
Core pesticide applicator training offered in
the
§ Regional reports
§ Weather news
Beth Bishop
Entomology
There is good news and bad news this week. The good news is that the second flight of European corn borer is pretty much over. The bad news is that the corn earworms have arrived in force!
Weather conditions last week resulted in strong winds from
the south that carried large numbers of migratory insects, including corn
earworms, into
Sweet corn and snap beans fields are at risk of damage from corn earworms. Tomatoes are sometimes also infested (the corn earworm is also known as the tomato fruitworm). Corn earworm moths prefer to lay their eggs on corn in the green silk stage. If the silk is brown and dried, it is no longer attractive to corn earworms and females are more likely to lay eggs on snap beans and tomatoes; if these crops are near corn fields they are at higher risk.
Sweet corn with green silk should be protected from corn earworm with insecticide applications. Capture, Warrior and Mustang Max are the most effective materials. Growers must ensure that their spray equipment is properly calibrated and that corn silks are adequately covered. Because of the large number of moths present, spray intervals should be 2 to 3 days when temperatures are in the mid to upper 80’s and 3 to 4 days when temperatures are lower (70’s to lower 80’s). Bt corn may require one application of a pyrethroid insecticide, especially as the silk begins to dry.
Snap beans and tomatoes with fruit are at risk of corn earworm infestation. Spray intervals for these crops should be 5 to 7 days. Spray intervals are a bit longer in these crops than in sweet corn because the earworm feeds partly on the outer surface of the fruit and thus is more exposed to insecticides. In areas with extremely high corn earworm numbers (the western regions of the state), the spray interval should be shorter and growers should use higher rates. The pyrethroids mentioned above are the most effective materials. Orthene (acephate) is registered for earworm control in snap beans and also provides some control, although it is limited to two applications per year and has a 14-day pre-harvest interval. Be sure to check Bulletin E-312 to find out which insecticides are registered for use on your particular crop. You can find this bulletin online at http://web4.msue.msu.edu/veginfo/E312.
Beth Bishop
Entomology
Aster yellows continues to be rare in southwestern
Aster leafhoppers collected last week from carrot fields in
west central
Dale Mutch
District Extension educator
A revised third edition of Managing Cover Crops Profitably has just been released by the
Sustainable Agriculture Network (SAN). Andy Clark, SAN Coordinator, has done an
excellent job improving and upgrading this book. I’m excited to announce that
several
Carolyn Randall
Pesticide Safety Education Program
MSU Extension and the Michigan
Department of Agriculture are sponsoring core pesticide applicator training
seminars in the
September 18, 8:30
AM - 4:30 PM at Bruce Township
Hall, 3156 E. 12 Mile Road, Dafter,
September 25,
8:30 AM - 4:30 PM at Bay College, Bays Room 952,
October 2, 8:30 AM - 4:30 PM, at Da Yooper Way Restaurant, 13909 US Highway 45, Bruce Crossing, Michigan.
This comprehensive commercial core training program will provide:
§ More professional development.
§ Enhanced applicator competency.
§ Improved safety practices and quality of services.
§ Up-to-date information on pesticide regulations and laws.
§ Recertification on commercial core in one day.
§ An opportunity for new applicants to take the intitial core exam.
At the end of the seminar, a short 20 question recertification exam based on information covered in the seminar will be administered by MDA. After completing the exam, applicators will receive 8 credits in commercial or private core.
Ron Goldy
There was a wide fluctuation in temperature for the past couple of weeks with highs from 64oF to 89oF and lows from 55oF to 67oF. For the two week period we have had 6 plus inches of rain and a total of 11 plus inches for August at SWMREC. Other locations in the area have had in excess of 20 inches.
Weather has seriously affected fruit quality and harvest activity and contributed to a general increase in disease levels. Excess rain has caused fruit cracking and contributed to Phytophthora on snap beans, tomatoes, peppers and vine crops. It has also reduced bee activity leading to reduced fruit set in summer squash and cucumbers. White mold is present on beans and downy mildew has been reported on cucumbers. Some fields have plant death directly from standing water. Cultural practices have also been severely hindered due to standing water and saturated soils.
Bill Steenwyk
The rain finally came, but in many instances it was too much
too late. Northern Ottawa alon with
On muck soils, celery growth and harvest continues. Most reports are positive, although some acreage had to be abandoned as wet fields delayed harvest and accelerated disease organisms. Onion and leek harvest is underway, with favorable fields and size being reported up to this point. New radish seedlings are just emerging. Beet harvest continues.
On upland soils, cabbage fields are developing well and being harvested where drainage is adequate. The same can be said of cucurbits and peppers, although more water-related challenges are evident. Acorn squash appear to have greater problems with pre and post-harvest rotting than other types. Late snap bean fields are in bloom and doing well.
As reported before, the sweet corn progress remains mixed. Seventy to eighty percent of the crop has been harvested. Wet soils are making it difficult to get the product off some fields during the very narrow harvest window. Previous dry weather makes ear size and fill uniformity an issue where irrigation couldn't meet water needs. Other fields, however, have produced a good crop.
Corn earworm moth trap counts are very high with a count of 307. Once again, wet field conditions may delay insecticide applications necessary to prevent yield and quality loss. Aerial application may be the only way to treat some fields.
Norm Myers
The rain may actually have a negative affect on asparagus, since I am getting reports of some new growth flushing. We probably do not have enough growing season left for the crowns to recoup the energy that they spend in putting up new fern at this point in the season.
Last week’s rains will give irrigators a break from the almost constant irrigation that was going on previously in carrots. Carrots do not have normal sized tops for this point in the season, but on the plus side, we also have very few bolters this year.
Since most of our pickles are not irrigated, our harvest season is pretty much over.
Zucchini viruses are cutting in to production of both yellow and green varieties. Recent rains may help with our previous blossom end rot problems. Powdery mildew problems have slowed since we switched away from the Strobi class of fungicides.
The winter squash and pumpkin crop will be lighter than usual due to the heat and drought. Maturity is also well ahead of normal. Viruses came late enough that they should not be a factor this year.
In sweet corn and snap beans, corn earworm catches were huge this last week, breaking all previous levels. Snap bean and sweet corn growers have stepped up their control measures, but we will have to see just how effective those strategies are.
Jim Breinling
Much needed rainfall was received during the past two weeks.
During the 8-day period from August 18 - 26, the Ludington MAWN station
recorded 2.55 inches and the
Harvest of carrots, slicing cucumbers, peppers, potatoes, parsnips, beets and turnips continues at a steady pace.
Onion harvest has begun this week.
Snap bean harvest continues with good yields reported
on irrigated fields. European corn borer trap counts this week continued at 0 0
0. The corn earworm trap counts on August 27 at the sweet corn site in
Hannah Stevens
Adequate moisture over the past two weeks has made a big difference to crop growth and development for late summer and fall crops although sticky soils have made harvest problematic at times. Growers are now busier than ever with crop protection, harvest and marketing, working down harvested crops, and sowing cover crops. Fortunately the past few days have been fairly pleasant. Weed growth is also benefiting from the warmth and moisture.
In sweet corn, corn earworm appeared in large numbers in the
past six days accompanied by a drop in European corn borer counts. I would
suspect the latter is due to trap location, which is near a field of harvested
corn. Common rust has appeared in some late fields.
Cucumbers which have not been on a tight spray program for downy mildew are probably severely infected at this point, judging by several fields and gardens I have seen. Hard squash is now on the market although yields are limited. Pumpkins are coloring.
There is good quality and quantity of tomatoes,
peppers and eggplants. With the wet
weather, warm air temperatures and abundant foliage on some varieties of
tomatoes, fungi have good growing conditions and I have seen early blight and
Septoria leaf spot that could get out of hand quickly.
Hard-to-find
vegetables such heirloom tomatoes, okra, purslane, tomatillos, squash vines
and husk tomatoes are delighting shoppers at farmers markets.
Jeff
Andresen
Agricultural Meteorology
Geography
A cool front will pass through
High pressure will move in behind the front by late tonight and early Thursday (August 30), leading to a fair and dry weather pattern that should last through most of the upcoming holiday weekend. Temperatures behind the front will fall back to below normal levels through Saturday, with a warming trend expected by the late weekend into early next week. Highs will fall back to the 70's across the state Thursday through Saturday, warming back into the 80's by Sunday and Monday of next week. Lows will range from the low 40's north to mid 50's south Friday, warming back into the upper 50's to mid 60's again by Labor Day.
A weak cool front
will approach the state by late Sunday, possibly leading to a few scattered
showers across the
Similar to last week, medium range forecast guidance suggests a relatively fast, zonal (west to east) flow along the U.S./Canadian border during the first week of September, with a relatively active storm track. Both 6-10 day and 8-14 day outlooks (for September 3-7 and September 5-11) call for precipitation to range from near normal levels across southern sections of the state with above normal totals across the north. During the 6-10 day period, near normal mean temperatures are expected statewide, while during the 8-14 day time frame, temperatures are forecast to range from near normal levels across northern sections of the state to below normal levels across the south. Forecaster confidence in both these outlooks continues to be lower than normal due to disparities in some of the forecast model guidance (not uncommon during this time of year as we enter the transitional fall season).