In this issue
§ European corn borer flight
§ Aster leafhoppers found
§ Cutworm damage
§ Postemergence weed control in onion
§ Section 18 label issued for Carzol SP® use to control thrips in dry bulb onions
§ Potato disease extension bulletins
§ Regional reports
§ Weather
Beth Bishop
Entomology
The number of European corn borer moths caught in pheromone traps increased for the week of May 30 to June 5 (see table). Most areas in Lower Michigan are at or above the 450 to 500 degree days base 50 required for the first flight (consult degree day table in this issue of the Vegetable CAT Alert or visit MSU’s Enviro-weather at: http://www.enviroweather.msu.edu
In most cases, this first moth flight does little damage to sweet corn. Small corn is not attractive and cannot support development of corn borers. If 20 percent or more of whorl-stage corn shows feeding damage, insecticides can be applied to the ear. The best time to apply such treatments is 10 days or more before tassel emergence or four days or less before tassel emergence. Consult Bulletin E-312, 2007 Insect, disease and nematode control for commercial vegetables insecticides registered for control of potato leafhopper on potatoes and snap beans. You can find this bulletin online at http://web4.msue.msu.edu/veginfo/E312.
European
corn borer moths caught in pheromone traps in different
|
Location |
Moths per trap |
|
|
99.2 |
| Macomb | 48.3 |
|
|
1.3 |
|
|
22.7 |
|
|
18.7 |
|
|
13.3 |
|
|
3.6 |
|
|
1.0 |
Beth Bishop
Entomology
Low numbers of aster leafhoppers are still being detected in
celery and carrot fields in western
Beth Bishop
Entomology
Damage from cutworms
was reported in several southeastern
Bernard Zandstra
Horticulture
The erratic spring weather has resulted in poor to fair preemergence weed control in many onion fields, as well as several other crops. Late planted onions are just reaching the mature one leaf stage and weeds are germinating and growing rapidly. Goal is labeled for application at the onion 2 leaf stage. It can cause onion injury if applied earlier. This leaves growers in a quandary about what to do.
Grasses can be controlled with applications of Fusilade, Poast or SelectMax plus a surfactant. In addition, all interplanted barley should have been killed by now. The new formulation of oxyfluorfen, GoalTender 4SC, is safer on onions and will cause less potential injury than Goal 2XL if applied to onions just entering the 2 leaf stage. One fluid oz of GoalTender contains the same amount of active ingredient as 2 oz of Goal 2XL.
The Nortron 4 SC label has been approved for onions. Nortron controls many broadleaves and is very safe on onions. Growers may try some Nortron in fields in which the weeds have gotten large before the onion 2 leaf stage.
Dual Magnum or Outlook should have been applied for nutsedge suppression by now. If one of these herbicides has been applied already, the other can be applied later to maintain suppression well into July. Remember that Prowl, Dual Magnum and Outlook all need at least 0.25 inch rain or irrigation to move them into the plant to be effective.
Chateau at the 3 to 6 leaf stage will improve both postemergence control and subsequent preemergence suppression of many broadleaves. It should be applied between applications of Prowl, Dual Magnum or Outlook. In tank mixes with GoalTender and Prowl H2O, it did not cause crop injury, but tank mixes with other formulations did cause crop injury.
Onion weed suppression during the next 4 weeks is critical to a good onion crop. Growers should use all measures within their means to keep the fields free of weeds. Onions will suffer yield loss from early season weed competition.
Walter Pett
Entomology
The Environmental Protection Agency (EPA) and the Michigan
Department of Agriculture (MDA) has issued a Section 18 label for the use of
Carzol SP® (Gowan®) for the control of thrips in dry bulb onions for
Growers should pay special attention to the plant back restrictions and to the application rate and maximum number of applications when using this product. See the Federal and Section 18 label for specific guidelines and directions at: http://www.ipm.msu.edu/cat07veg/PDF/6-6Sec18carzol.pdf
Phill Wharton
& Willie Kirk
Plant Pathology
Seven new high
resolution potato diseases extension bulletins are now available for purchase at
http://www.emdc.msue.msu.edu/ for
$1.50 each. The new group of publications includes the recent potato late
blight bulletin and bulletins on early blight, pink rot, Fusarium dry rot,
Rhizoctonia diseases, potato common scab, white mold and seed piece management.
For more information, call 517-353-6740. You can also download these bulletins
from this web page http://www.potatodiseases.org/extensionpubs.html
as PDF files from our late blight website.
Also at http://lateblight.org daily updates of potato
late blight risk are available for all the Michigan Automated Weather Network
sites in
Ron Goldy
Temperatures during the week ranged from highs of 61oF to 87oF and lows from 45oF to 67oF. The area received from 0.5 to an inch or more rain. Transplanting conditions have been excellent.
Asparagus fields are finished, and growers are applying post-harvest weed control and fertilizer.
Tomato, pepper and eggplant transplanting continues. Early, non-tunnel-grown tomatoes and peppers are at bloom and early fruit set. Tunnels are being removed from tunnel-grown plantings.
Watermelon and cantaloupe transplanting is mostly complete.
Cucumbers have responded well to warm temperatures and those grown under tunnels have three to four-inch fruit. Early, non-tunneled plantings of cucumbers and squash are in early bloom. Still no reports of cucumber beetles at this time.
Pumpkins are being planted.
Sweet corn growth is at 12 to 14 inches.
Early potatoes are in bloom. Colorado potato beetle adults are active and eggs can be found.
Bill Steenwyk
West Central Michigan received 0.3 to 2.0 inches of
much-needed rain last Saturday and Sunday. It frequently came in heavy
downpours accompanied at times by medium to large hail. Some orchards in the
The overall condition of our vegetable crops continues to be
excellent. Muck crops, including celery,
onions, leeks, radishes and red beets are progressing well in Van
Buren,
On upland soils, most crops also look good. The cabbage crop is outstanding, with development being ahead of normal. Some feeding damage from diamondback moth and imported cabbage worm larvae is evident, but not severe. Most others, including squash, zucchini and beans are developing well. Warm-season vegetables such as peppers and tomatoes have been transplanted, with no problems evident.
Sweet corn has
grown well, but I have found fields in
A few upland fields have been plagued by tough, perennial weeds such as hemp dogbane, horsenettle and field bindweed. I'm sure that others such as Canada thistle and hedge bindweed are also around. Growers should move quickly to control these when first sighted, spot spraying with a backpack sprayer is effective and doable when present in small spots.
Norm Myers
In asparagus, most growers are over two thirds of normal tonnage already harvested and most are hopeful that they can go another two weeks yet. The fresh market is still pretty hot and our processors wanted more asparagus even before the three million pound USDA purchase was announced. Common asparagus beetle continues to bother some producers and leave others alone. Part of the problem with this pest is that the switch to processed spears and fresh market means that the receivers are less tolerant of beetle eggs than those that receive just cuts and tips. Aecial lesions of rust are showing up in fern of one and two-year-old fields. Two-year-old plantings are mostly laid by for the season now.
In carrots, stands are variable. Small grain cover crops have been killed on all but the youngest fields. Scouts report some leafhopper numbers, but globular springtails have been the most serious pest problem so far this spring, and in some places required two sprays to kill. Some irrigation had begun before the weekend’s rains.
Winter squash and
pumpkin fields are beginning to
emerge and stands generally look good. Weed control may be uncertain, because
we didn’t have rain to activate herbicides until very recently. To my knowledge,
I have yet to catch a soybean aphid in the trap in
Some early processing and fresh zucchini were planted early last week and the rest of the processing crop is going in now.
In snap beans, early crops are emerging and stands look pretty good. The late crop will not be planted until the end of this month or early July.
In sweet corn, most plantings for local consumption are emerged. I did catch three European corn borer moths in my traps near Hart.
Jim Breinling
Temperatures in the area during the past week were above
normal with nearly 100 degree
days base 50 accumulating over a four day period. Daytime highs reported
were 86.2ºF at
Weed control and killing of barley continues in carrot fields. Planting will finish late this week or early part of next week.
Growth of onion crops seem to have slowed during the past week, essentially at the 3 leaf stage, 8-10 inches in length.
Spinach growth has been rapid this past week, now at 6-8 true leaf stage.
Winter squash plantings have emerged rapidly and are in cotyledon stage.
Snap bean fields
have also emerged rapidly and fields where European corn borer traps are
located are at cotyledon stage. European corn borer trap counts in
Hannah Stevens
We experienced two days in the 90ºF range this week, May 31 and June 2, and then a sudden drop yesterday to a high of 66ºF with a low this morning of 38ºF in Central Macomb. Fortunately, soil temperatures are remaining in the 60ºF range. There may well have been frost in low-lying areas that have already been hit with frost on sensitive crops once or twice. Field work on mineral soils has been difficult this week with frequent rain, from light sprinkles to downpours with a total of 2 inches or more.
In sweet corn, European corn borer flight is well underway with 25-75 male moths captured this week. No damage to the corn is reported yet. Growers are scouting fields for signs of Stewart’s bacterial wilt. Corn is growing rapidly and of good color. With so many new cultivars, it is hard to make generalities about emergence, growth and development.
Leafy greens are in good supply now at retail markets.
Early snapbeans are budding. Bean leaf beetle (see picture) may be present on unprotected beans, but the threshold for bean seedlings is relatively high. Consult bulletin E-312 for recommendations.
In tomatoes, peppers and melons, dark sided cutworm injury (see picture) to newly
transplanted seedlings was reported on several farms. These caterpillars overwinter
in the egg stage on weeds and debris, and begin feeding in May. There are a
number of resources including this one from the
Tomato stakes continue to be set (see picture).
Potatoes on plastic are filling out. Colorado potato beetle adults may need control at this time.
Paul Marks
Rain over this last weekend provided between two and three inches of water to our area. Soils were dry enough to absorb this amount; however, most areas received two events coming so fast it pounded in lower areas of the fields. Standing water has damaged crops in many fields. We have stayed cloudy and cool for the last several days minimizing the crop damage from the saturated soils.
Sweet corn is at a wide range of development in our area: from still to be planted for later harvest, to tasseling and silking in several fields that were tunneled. The earliest fields planted without plastic now have tassels developing in the whorl. Corn borer traps this week averaged 23 moths per trap, up from last week’s six per trap. There is very little Stewart’s wilt seen in our fields.
Tomatoes for market are being staked with earliest plantings showing the first fruits. Earliest planted processing tomatoes are filling the twin rows.
Peppers have made very good growth this last week and are beginning to flower in earliest planted blocks. Latest planted fields needed the rain.
Cucumbers, which were tunneled, now have fruits developing, while earliest open fields planted are beginning to run off of the plastic. Cucumber beetles have been very few.
Zucchini and summer squash are just beginning to flower, except the earliest plantings which were tunneled, are at first harvest.
Cabbage planted early is developing heads with harvest expected to start next week on several farms. Adequate moisture in soils will make for good quality packs. Worms have been at low pressure. Maggot damage has ended. Water has damaged this crop in many fields.
Potatoes in our area have a wide range of development from just emerging to flowering and developing tubers. Leafhoppers have continued to increase this last week to a point that untreated fields are now three to four times above threshold. No potato beetles in our fields so far this year. No aphids found in this crop.
Jeff
Andresen
Agricultural Meteorology
Geography
The upper air trough that brought showers and thunderstorms
to much of
Following the passage of the front, high pressure is expected to move in for the weekend, leading to cooler, fair and dry conditions Saturday and Sunday and likely into early next week as well. Temperatures will fall back to near normal levels over the weekend, with highs generally in the upper 60's to mid 70's and lows in the 50's. Rainfall will be possible once again by the middle of next week.
Further ahead, medium range forecast guidance is consistent
in calling for the formation of an upper air troughing feature across western
sections of the
Users of the Enviro-Weather system have likely noticed outages at several of our weather station sites, which are associated with the widespread thunderstorms and lightning during the past few days. Our technicians are working to bring all of the missing stations sites back on line as soon as possible. We apologize for any inconvenience or trouble caused as a result of these outages.