June 20, 2007
In this issue
§ Pheromone trap update
§ Look out for leafhoppers!
§ Aphids and viruses
§ Downy mildew update
§ Urea plus Agrotain
§
§ MSU Student Organic Farm field days
§ Regional reports
§ Weather
Pheromone trap update
Beth Bishop
Entomology
The numbers of European corn borer moths caught in pheromone traps last week were low in most locations (exception, Macomb County--see Table) We are nearing the end of the first moth flight (see degree-day totals (base 50) in this issue of the Vegetable CAT Alert or visit MSU’s Enviroweather at http://www.enviroweather.msu.edu). However, some sweet corn is at risk from corn borer larvae that are now feeding in the whorl. When tassels emerge, these larvae move down the stalk to the developing ears. If 20 percent or more of the whorls have larvae or feeding damage, apply insecticides to the whorl four days or less before tassel emergence. Consult Bulletin E-312, 2007 Insect, disease and nematode control for commercial vegetables insecticides registered for control European corn borer in sweet corn. 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 |
|
|
5.7 |
|
|
0.0 |
|
|
0.0 |
|
|
1.7 |
|
|
0.0 |
|
|
0.0 |
|
|
0.0 |
|
|
43.0 |
|
|
0.0 |
A few corn earworm moths were caught in pheromone traps in
Oceana and
Beth Bishop
Entomology
Aster leafhopper numbers remain low in carrot and celery
fields in west
Potato leafhopper numbers, on the other hand, are very high in some potato and snap bean fields. (View photo) Potato leafhoppers damage these crops by injecting their toxic saliva during feeding. By time growers notice the resultant “hopperburn,” the damage has been done and yield will be reduced. (View photo) Growers should scout fields for potato leafhopper and apply insecticides if numbers are over threshold. Potato fields can be sampled for adult leafhoppers (with wings) by taking 20 sweep net samples in five different areas of the field. If 25 or more adults are found in 100 sweeps, treatment is warranted to prevent hopperburn. Fields should also be sampled for the wingless nymphs by turning over and examining a potato leaf from the middle of the canopy on 25 plants. If more than 2 nymphs are found on 25 leaves, treatment is recommended.
Growers should scout snap beans by making 20 sweeps in five different locations in the field. Snap beans are more vulnerable to leafhopper damage when small, and one or more leafhopper per 2 sweeps (50 per 100 sweeps) during the seedling stage requires treatment. From the trifoliate to bud stage, the treatment threshold is one leafhopper per sweep. 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.
Beth Bishop
Entomology
With the recent reports of soybean aphids being captured in
suction traps throughout
For vegetable growers the answer, unfortunately, is not much. Soybean aphids do not live on vegetable crops. Any aphids you find on your vegetable are not likely to be soybean aphids. Any alate (wingless) aphids on vegetables are definitely not soybean aphids, since soybean aphids cannot reproduce on vegetables. Soybean aphids may land on melons, beans and peppers in an attempt to find their host plant (soybean), but they will not stay. Instead, they will “taste” the plant to determine if it is a soybean plant, and if it does not “taste right” they will fly off again.
During the few seconds it tastes the plant, any viruses that it is carrying can be transferred. No insecticide works fast enough to prevent this transmission. Insecticides do not prevent virus transmission in most vegetables and any application of insecticides to prevent viruses does more harm than good by killing natural enemies. The most effective way to reduce the incidence of viruses is to plant virus resistant varieties, avoid late plantings (during July and August when aphids are flying) during years of high soybean aphid populations (like 2007) and manage weeds in and around vegetable fields.
Mary Hausbeck
Plant Pathology
There are no confirmed reports of downy mildew in
Table 1. Recommended
products for managing downy mildew on pickle.
|
APPLIED BEFORE DISEASE (7-day intervals) |
APPLIED AFTER DISEASE (5-day intervals) |
|
— Gavel 75WG (5 day PHI) |
— Previcur Flex 6SC (2 day PHI) |
|
— Previcur Flex 6SC (2 day PHI) |
— Ranman 3.6SC (0 day PHI) |
|
— Ranman 3.6SC (0 day PHI) |
— Tanos 50WG (3 day PHI) |
|
— Tanos 50WG (3 day PHI) |
|
|
Alternate products and mix each with either: — Dithane (mancozeb) 3 lb or — Bravo (chlorothalonil) 1.5 pt |
Alternate products and mix each with either: — Dithane (mancozeb) 3 lb or — Bravo (chlorothalonil) 2 pt |
Chemical control must be focused on using the most effective products, alternating the products and applying fungicides at short intervals. Results from our downy mildew research in 2005, indicate that an effective spray program includes the following: Previcur Flex (propamocarb hydrochloride) plus Bravo (chlorothalonil) alternated with Tanos 50DF (cymoxanil + famoxadone) plus mancozeb.
The initial sprays for the 2006 trials were applied when plants had one true leaf and no disease symptoms were apparent. Ten applications were made on August 1, 7, 11, 15, 21, 26 and 31; September 6, 13 and 20 following a five to seven day spray schedule. Plots were visually evaluated for necrotic leaves on September 11 (see Figure 1). Fruits were hand-harvested four times from the entire 15 ft of all treatment rows on 5, 11, 18, and 25 Sep. Products that looked favorable in our 2006 field studies include Ranman 3.6SC (cyazofamid), Gavel 75WG (mancozeb + zoxamide), V-10161 4FL (fluopicolide), Tanos 50WG and Previcur Flex 6SC. Each of these products should be mixed with either Dithane or Bravo (see Table 1).
Darryl Warncke
Crop & Soil Sciences
Vegetable growers have been primary users of ammonium nitrate to supply additional nitrogen. With this material, there is little concern about volatile loss of nitrogen when it is applied on the soil surface and irrigated or rained in. However, ammonium nitrate is difficult to obtain these days, so vegetable growers are left looking for alternatives. Many are using urea. When urea is spread on the soil, there is the potential for volatile nitrogen loss as the urea is converted into the ammonium form. This can be quite significant when soil temperatures are high, as they are now. Losses can range from 10 to 25 percent within two to three days when soil temperatures are near 75oF, and the urea is not irrigated or rained in with a 0.5 inch or more of water.
Urea can be treated with the product Agrotain, which is a urease inhibitor, to slow the rate of conversion of the urea into the ammonium form. By doing this, it reduces the potential for volatile nitrogen loss. Agrotain can be quite effective for at least two weeks. During this time period, there is usually a good probability of measurable rainfall to move the urea into the soil. So if you are using urea as a surface broadcast, consider having it treated with Agrotain or pray for rain right after the application. Note, when urea is incorporated into moist soil, volatile nitrogen loss should be minimal and use of Agrotain will not be necessary.
Lyndon Kelly
Extension Irrigation Educator
MSU Extension/ Purdue Extension
New wells and surface water withdrawals in
or from St. Joseph County MSU Extension at http://www.msue.msu.edu/stjoseph then navigate to the link for irrigation on the left side.
The latitude and longitude coordinates for the location are required for all new large scale withdrawal location. This information may be provided by handheld GPS units or the groundwater mapping website (http://gwmap.rsgis.msu.edu). Many MSU Extension offices or your local Conservation District office can assist with the use of finding the latitude and longitude coordinates. Providing the latitude/longitude location of withdrawals will allow mapping and analysis of effects of withdrawals on groundwater and stream base flow in the watershed basin.
Information at the St. Joseph County
MSU Extension website (http://www.msue.msu.edu/stjoseph)
can assist in estimating water use for irrigation and other agricultural water
uses. Lyndon Kelley, irrigation management educator for MSU Extension can
answer many of the questions related to
An estimate of expected water use by the month is needed. Most irrigators will estimate their water use from experience multiplied by the number of acres irrigated. As an example: 100 acres with 1.5 inches of irrigation applied in June would have an estimated water use of 150 acre inches for the month. Three inches of estimated irrigation needed in both July and August and 1 inch in September, would give an estimated annual water use of 550 acre inches for the year.
The registration process also calls for an estimate of consumptive water use. Consumptive water use is the amount of water that is lost from the area of withdrawal. Since most water pumped for crop irrigation ultimately goes into evapotransporation, the consumptive use is estimated to be high or about 90 percent. Water used for harvest cooling is mostly retuned back to the surface or groundwater so the consumptive use is estimated to be low or about 5 to 10 percent.
The registration process establishes a “baseline capacity” based on the available withdrawal capacity of a system. The baseline capacity of the system should be reported as pump capacity in gal/min along with a pump and system description, which is compatible with the well log. Baseline capacity applies to both wells and surface water withdrawals. Please note: You should report this baseline capacity value on the registration form on the line listed as “rated capacity.”
For further information, water resource specialist, Abigail Eaton of the Michigan Department of Agriculture Environmental Stewardship Division heads up the registration process for large water withdrawals. She can be contacted at 517-241-3933 or eatona@michigan.gov.
Susan Smalley
C.S. Mott Group for Sustainable Food Systems,
The Michigan State University Student Organic Farm with support from the USDA Risk Management Agency is featuring two farm field days this summer to highlight two sustainable production strategies for small scale and limited resource specialty crop farmers.
Hoophouses
and Passive Solar Greenhouses for Protected Cultivation
Tuesday, June 26, 9:00 AM – 4:00 PM
§ This workshop will include:
§ Design options for a range of costs and sizes
§ Construction methods including cold frames and small scale build-your-own
§ Crop selection and scheduling
§ Soil preparation, building soil organic matter and fertility management
§ Planting, growing and harvesting methods (we expect to be harvesting tomatoes)
The workshop is presented by Adam Montri, MSU and MIFFS
Hoophouse Outreach Specialist, and Dr. John Biernbaum, MSU Professor of
Horticulture.
Edible forest gardening: intensive
perennial and annual permaculture
Tuesday, July 10, 2007, 9:00 AM – 4:00 PM
§ The edible forest gardening workshop will include:
§ Introduction to principles of the edible forest garden and permaculture
§ Mimicking a natural forest ecosystem, guilds, three dimensional planning
§ Comparison of a forest, orchard, annual vegetable and mixed polyculture settings
§ MSU Edible Forest Garden Design and Planting, a 0.75 acre diverse planting
§ Selection of perennial tree fruit, nut, small fruit and herbs for the edible forest garden
Presenters for this workshop are Jay Tomczak, MSU Graduate Student and Certified Permaculturalist, and Dr. John Biernbaum, MSU Professor of Horticulture.
Both workshops will take place at the Michigan State
University Student Organic Farm, located at the MSU Horticulture Teaching and
Preregistration is required as enrollment is limited. To register, contact Adam Montri at admontri@anr.msu.edu or 517-432-3381. Also, please bring your own lunch. A walk-in cooler is available to refrigerate lunches. Fresh vegetables and water will be provided.
Ron Goldy
Temperatures during the week ranged from highs of 77 to 91oF and lows from 61 to 71oF. The area received spotty rain amounting from zero to one or more inches. At SWMREC, we have had 2.88 inches since April 1 and 0.83 inches since May 1. Many fields are extremely dry and showing signs of drought stress.
In general, there are still few disease and insect problems to report. The biggest concern continues to be irrigation needs.
Tomato, pepper and eggplant continue to grow well, providing they have adequate irrigation. All three are in the process of blooming and setting fruit even on non-tunneled plantings. Few disease or insect problems have been noted, however, there are reports of early blight on tomatoes.
Watermelon and cantaloupe are in flower. Cucumber, zucchini and yellow squash harvest is underway.
Early sweet corn is beginning to tassel.
All stages of Colorado potato beetle can be found.
Bill Steenwyk
High temperatures from Van Buren through
Crop reports
On muck soils, onions, celery, leek, red beets and radishes are doing well. Very few aster leafhoppers are found. Disease pressure is slight. Early-planted red beets will soon be harvested.
Upland soil production continues to progress well. Irrigated
tomatoes, peppers, squash, cabbage, beans, etcetera, have few serious problems. I have not seen, but
heard reports of severe sandblast damage arising from the high winds of
June 7. One
The sweet corn crop is doing fairly well, but I have seen occasional yield-reducing problems. Non-irrigated fields, especially on coarse-textured soils, are showing drought stress. With earlier plantings beginning to silk, soon-to-pollinate and begin grain fill, additional drought stress is a serious concern. Plants that were systemically infected with Stewart's bacterial wilt are now severely stunted and are not likely to produce a harvestable ear. See the photo showing an infected plant surrounded by non-infected. Substantial smut infection has appeared in one field.
I occasionally see signs of micronutrient deficiency, usually manganese. These problems often appear when pH in too high. On organic soils and high-organic matter mineral soils, I have seen this as the pH moves into the low 6’s. Many crops experiencing this will display yellowing between the veins, predominately on the newer leaves (if it were on the older leaves, the likely issue would be magnesium). Growers and scouts should be careful to watch for this and apply foliar manganese or another nutrient.
Norm Myers
Rain fell across
In asparagus, production in the last fields is being shut down as winds allow. The rain of June 19 should have been perfect for activating recently applied post-harvest fertilizers and herbicides. Heavy weed growth will require a burn down material in most fields, with most growers using glyphosate. Rust and purple spot lesions can be seen on fern developing in young fields, picked less than a full season. I have a Tom-Cast sensor out in fern in a young field, but will wait until early July to place sensors in full-season fields. Common asparagus beetle is also active. Asparagus production will be off of last year’s pace by a substantial amount. Most growers are blaming damage from phytophthora spread in the flooding during the spring of 2004 and a shortage of labor for the low yields.
In carrots, yesterday’s rain gives everyone a break from irrigation, and growers are hopeful that the break in the heat will be better growing weather for the carrots. There are some thin spots in the fields, especially where wind damage has occurred. I will launch my Tom-Cast sensors in carrot fields later this week.
For winter squash and pumpkins, rain should help these crops a lot, since most of these fields are not irrigated. Weed control may become a problem now, since winds shortly after planting blew away most of the herbicide.
Growers are still planting zucchini, and have been watering fields in order to plant. Weed control may be better in this crop than squash and pumpkins due to yesterday’s rain.
In sweet corn, I did catch eight corn earworm moths at my trap, but there were no corn borers present.
In snap beans, growers will be planting the late crop beginning next week. Early crop growers are reporting a lot of potato leafhopper present.
Jim Breinling
Temperatures were above normal during most of the seven day
period until the rain and cold front that came into the area about midnight Monday,
June 19. The front provided much needed rainfall in most of the area. 1.92
inches was reported at the Ludington MAWN station. Again, the rainfall amounts
were less as the front moved south and east with only 0.44 reported at the
Fremont MAWN station. Grower reports in the
Carrot planting has been completed. Early fields are now well established and at the 6 to 8 leaf stage. Hot weather has made it difficult to keep up with weed control in some fields. Aster leafhopper counts are still reported to be very low.
I have seen fairly severe damage to a pepper field caused by the strong winds on June 7, plants will survive, but harvest will be delayed.
Spinach plantings are growing rapidly and nearing harvest. Cooler weather is needed for this crop at this time.
First plantings of potatoes are beginning to bloom.
Winter squash plantings are growing well with above normal temperatures. Weed control with cultivation and hoeing is being done at this time in most fields.
First slicing cucumbers
grown under Haygrove high tunnel systems were harvested on June 12 in the
European corn borer trap counts were again 0-0-0 this week
at the snap bean site in
Corn ear worm traps will be set up next week at sweet corn
locations in
Hannah Stevens
A very warm and
humid week with heavy dews and extended periods of leaf wetness. The high
temperatures have ranged from 83-93oF. Crop development is rapid and
so is weed growth. Rainfall on Monday evening was light; 1.0-1.5 inches and more
would be welcome. Both trickle and overhead irrigation is underway.
In sweet corn, European corn borer flight took a sharp
upturn this week with an average of 43 moths per trap. I walked several fields
yesterday and noted many larvae 5-8 mm long on the tassels on corn in full row
tassel. The tiny larvae had been exposed to pyrethroid sprays and were dead or
dying due to residual control. A small percentage had moved from the tassel to
the stalk and were in a position to enter the ear. Corn in pre-row tassel also
had larvae down in the whorl. All fields need to be scouted now. In this area,
early sweet corn is far ahead of field corn in development, and so this first
generation is attracted to the taller sweet corn. A small amount of Stewart’s wilt
was observed in two early varieties.
Jack-O-Lantern pumpkins
are developing true leaves. There
are reports of crows doing significant damage to stands by pulling seeds. I
also had a second-hand report of squirrels locating and eating seeds.
Early seeded winter
squash and large pumpkins are beginning to show buds. Striped cucumber
beetle has been controlled in a number of fields I walked.
Row covers have all
been removed from muskmelons and watermelons. Bees, both domestic
and wild, seem to be working, and fruit is beginning to set.
Beets, onions and peas have joined other cool season vegetables at markets. Broccoli is
beginning and very early new potatoes will be on the market this weekend.
Tomatoes have been tied once or twice, and early
plantings have small fruit. The windy conditions of the last couple weeks may
result in incidences of bacterial speck damage to foliage as a result of
blowing sand damage. I have seen one case of this and there is probably more.
Paul Marks
It has been hot most of this last week with very little moisture coming from two events on Monday and Tuesday bringing between one quarter and one half inch of moisture to most of our area. Potential evapotranspiration during this same time has totaled 1.94 inches of moisture needed by plants from the soil. Degreedays base 50 now total 957 putting us about five calendar days ahead of a long term normal. Irrigation systems are all running.
Tomatoes for market continue to size with first harvest several weeks away on most farms. Processing tomatoes for early harvest are now yellow with flowers. No problems seen in either of these crops.
Sweet corn in early planted fields is beginning to silk. In plantings that were tunneled, harvest is a week or more away. There were no corn borer or corn earworm moths in my traps this week. Larvae in fields that have not been treated are now more than an inch in length. Treated fields appear to have very good control with only one application.
Cabbage harvest is well underway with some growers reporting smaller head size than they had expected. Cabbage planting for late summer harvest has been difficult to get started due to the high day temperatures and low humidity. Even where irrigated, the plants small root systems have struggled to find enough moisture to sustain the tops.
Vine crops have made great growth with the warm weather, especially where good irrigation management has been in place. Slicing cucumbers are being harvested from tunneled fields, while open fields will begin on some farms early next week.
Potatoes are at all stages of growth from just fully emerged to tipping and opening of tall vines in earlier planted fields. This crop has suffered these last two weeks in the high temperatures, even with irrigation. Fields that are developing tubers just can’t seem to get enough water. Leafhoppers continue to be a problem even in some treated fields. I have had numbers as high as 40 per 20 sweeps.
Peppers have made very good growth this last week. I have been in several fields where aphids are present. Some growers have already made one insecticide application in anticipation of the soybean aphid and its potential to bring virus to this crop.
Jeff
Andresen
Agricultural Meteorology
Geography
Showers and thunderstorms associated with a cool front
moving across
Looking ahead, the outlooks in general suggest a gradual
return of warmer and drier than normal weather. In the near term, a weak
frontal boundary is forecast to cross the state late Wednesday into Thursday
and bring at least a chance for showers. With only limited moisture in advance
of the front, however, any precipitation that does develop will likely be
widely scattered in nature with most amounts remaining less than 0.25 inches. Best
chances for rainfall through Thursday morning will be across northern sections
of the state, with most southern sections remaining dry. A second frontal
system will approach the state by Friday, bringing another chance for rainfall.
Once again, only widely scattered showers and a few thundershowers are
expected, with many areas remaining dry. In contrast to the Wednesday/Thursday
event, best chances for rainfall late Friday into Saturday will be across
southern sections of the
Temperatures during the next couple of days will remain at near to slightly below normal levels, gradually warming to above normal readings by the weekend. Look for with highs ranging from the low 70's north to near 80 south through Thursday, increasing into the 80's by Sunday. High temperatures near or above 90EF are possible once again by Monday of next week. Low temperatures will range from the upper 40's north to low 50's south through Thursday, increasing into the 60's by the weekend.
Medium range forecast guidance is suggesting the formation
of an upper air ridge across the Great Plains and western