August 1, 2007
In this issue
§ European corn borer/corn earworm update
§ Green peach aphids on potato
§ Controlling phytophthora disease on pepper
§
Enviro-weather delivers weather-driven
production management tools to
§ Regional reports
§ Weather
Beth Bishop
Entomology
In most areas of southern
Sweet corn with ears, as well as peppers and snap beans with fruit, are vulnerable to damage from offspring of this second moth flight. These crops should be treated preventatively to avoid worm in ears and fruit. Eggs are laid on the underside of leaves. Upon hatching, larvae feed for a brief time on the leaf surface and then bore into the ears or fruit where they are protected from most insecticides.
To prevent worm damage to ears or fruit, it is essential that sufficient insecticides be present on the plant when larvae hatch. See Bulletin E-312, 2007 Insect, disease and nematode control for commercial vegetables for insecticide options for control of European corn borer. You can find this bulletin online at http://web4.msue.msu.edu/veginfo/E312.
Walter Pett
Entomology
Colonies of green peach aphids have been found in several
potato fields in lower
Consult MSU Bulletin E312, 2076 Insect, disease and nematode control for commercial vegetables, for a list of insecticides registered to aphids. You can find this bulletin online at http://web4.msue.msu.edu/veginfo/E312/index.cfm.
Mary Hausbeck and H. Rogers
Plant Pathology
Phytophthora capsici
attacks both bell and hot peppers in
Phytophthora symptoms can be hard to spot on pepper, and infection may occur days before any visible signs of disease appear. The most obvious symptom of Phytophthora in peppers is the wilting and death of plants. During times of high relative humidity and wetness, a layer of spores may cover the pepper like “powdered sugar.” Roots and crowns can potentially turn brown or black, and dark lesions will periodically appear on the skin of the fruit.
Because of the severity of Phytophthora, early management is the best recommendation to
prevent spread. Once a field has been exposed to Phytophthora, scout fields regularly
for any signs of disease. It is possible to plant pepper varieties that
are somewhat resistant to
Phyophthora, or to plant a Phytophthora tolerant variety.
Warm, wet weather is most conducive to the
spread of Phytophthora. The
disease can live in the field at least ten years, and is
problematic for many vegetable crops. When planting peppers, do not
plant into a field rotation with other susceptible crops like tomatoes,
zucchini, squash, cucumbers, beans, melons or
pumpkins. Plant peppers into raised beds with black plastic
and only in well drained sites. If irrigation is
necessary, it is best to use drip irrigation and to not use
surface water as a source of irrigation.
One of the best defenses against Phytophthora is to spray fungicides early and often. It
is important to make sure that there is adequate canopy coverage so that Phytophthora has no chance of infecting
the plant. It is wise to rotate between fungicides so the pathogen
does not build up immunity to any one fungicide.
When applying a foliar application of fungicide, it is important to keep spray intervals short. Make sure to apply the fungicide before a rain, and come back as soon as possible after a rain.
If Phytophthora
becomes a problem, harvest the fruit as early as possible
and keep the harvested fruit in a cool, dry environment.
Plow under the diseased portion of the field, and the healthy
looking plants that border the area. View pdf of this article online
at:
http://ipm. msu.edu/cat07veg/PDF/8-1pepper.pdf
|
Product |
Active ingrediant |
|
Ridomil Gold/ Ultra Flourish |
mefenoxam |
|
Ridomil Gold Copper |
mefenoxam / copper hydroxide |
|
ProPhyt / Phostrol |
phosphorous acid equivalents |
|
Kocide, Champ / Cuprofix Disperss |
copper hydroxide /copper sulfate |
|
Manex |
maneb |
|
Tanos |
famoxadone + cymoxanil |
|
Acrobat / Forum |
dimethomorph |
Mark Trent
Enviro-weather
MSU’s Enviro-weather web site came online in July of 2006 to
provide a one stop site for weather-based decision making information to
Enviro-weather is designed to be a dependable, sustainable weather-based system for pest, natural resource and production management decision-making. Users access the system through a web site: www.enviroweather.msu.edu. Information at the web site integrates near-real-time weather data from the Michigan Automated Weather Network (MAWN) and other weather systems with modeling tools and information resources such as the MSU IPM Resources web site.
The backbone of the system is the Michigan Automated Weather
Network (MAWN) with about 50 stations located throughout
The heart of the system is the science-based models that provide decision support to Enviro-weather users. Insect life stages, plant maturity and crop disease risk are among the many factors linked to hourly, daily and seasonal weather patterns. Models that quantify these links have been and are currently being developed by researchers at MSU and other universities and research facilities. Models and reports suggested and evaluated by workgroup members are programmed into the website, linking to hourly or daily weather data, making results available on demand at the site.
The brain of the system is the IPM Resources website (www.ipm.msu.edu).
This site contains a wealth of agricultural information with over 2,500
individual web pages and averages over 50,000 hits per week. Enviro-weather is
integrated with quick links to the IPM Resources web site for background
information on pests and for quick access to other resources like the Crop Advisory Team (CAT) Alerts. Specific
pest information is linked to relevant models. For example, a fruit grower
using the predictive model for plum curculio in tart cherries at Enviro-weather
will find a link to information developed by MSU Extension educators and
specialists about the pest.
The guts of the system are the self-identified workgroups who organize to provide direction on tailoring the information system to meet industry needs. These workgroups typically include web site users such as farmers, resource managers and consultants along with MSU specialists and Extension educators. They are essential in identifying needs and priorities such as: What relevant weather-driven models/information are available for integration into the system? Which educational, extension and research resources should be linked to the system? What supplemental external resources for research, partnerships, funding are needed? Are additional weather stations needed and if so, how will they be supported?
The workgroup met in April to identify weather-driven products
and information that are available and applicable to the needs of
As a result of the input from the workgroup, products now available on the Enviro-weather vegetable production page include: Links to National Weather Service radar and forecasts; a summary of current conditions that incorporate rainfall, growing degree days and wind speed into one easy to read table; a soil conditions report that includes temperature and moisture; and an overnight temperature report that not only gives an hour by hour breakdown of last night’s temperatures, but also provides a forecast for tonight’s low temperature and dew point temperatures. Irrigation resources include a potential evapotranspiration report and an interactive irrigation scheduler. Under pest models and predictions you will find links to MSU DSV page for TomCast, Northern Illinois University’s Insect Migration Risk Forecast, North Carolina State University’s North American Plant Disease Forecast Center for Cucurbit Downy Mildew, Penn State’s PestWatch site that gives trap catches for corn earworm at many locations across the United States and the North Central Regional Soybean Aphid Suction Trap Network. Products in development include a variety of insect management models and programming the irrigation scheduler for more vegetable crops. Visit www.enviroweather.msu.edu to find our more.
Ron Goldy
Weather
Temperatures during the week were generally near average (83oF) with highs of 77oF to 89oF and lows from 60oF to 67oF. Rainfall was quite variable across the area with amounts ranging from none to over 4-inches. Irrigation continues to be a top priority.
Crop Reports
Virus and phytophthora symptoms continue to show up in vine crops, but not at serious levels. Blossom end rot has shown up in some pepper and tomato fields, especially those just coming into production. Two-spotted spider mites have become a problem in some watermelon and tomato fields. Some corn plantings have aphid levels in need of control. Verticilium symptoms are present in eggplant.
Bill Steenwyk
The past week was hotter, but not quite as dry as the week before in West Central Michigan. Rainfall in the district ranged from just a smattering to 0.75 inch. The key to crop health remains just as it did before: the availability of timely irrigation. Where this is in place, crops look quite good.
On upland, irrigated soils, cabbage, cucumbers, melons, tomatoes, peppers, squash, zucchini, snap beans and sweet corn continue normal development at various growth stages, including harvest. The relatively few non-irrigated vegetable fields are in the same poor, stressed condition as hundreds of thousands of field crop acres across the state.
A couple of benefits from the dry weather are the low levels of disease and the low level of compaction to soils from heavy field machinery. Yield loss from soil compaction is as real and costly as that from drought, floods or pests.
Norm Myers
Weather continues to be hotter and drier than normal, with irrigation going flat out where its available. Surface water sources are beginning to dwindle, and those who use them may soon have to make some decisions as to which crops they will keep irrigating.
In asparagus, disease severity value totals are going up surprisingly quickly considering how dry it has been. Growers need to keep current with disease severity value totals at a site near them, since the first week of August is often when purple spot gets out of control in asparagus fields. Rust is also present and should not be ignored. Common asparagus beetle adults and larvae are also present, but are generally under control.
In carrots, disease severity values have gone up even faster in this crop because of irrigation. All three foliar blights (alternaria, cercospora and bacterial) are present in our area. Aster leafhopper numbers are variable. Where irrigation is not available, the carrots are really suffering.
Pickle/cucumber harvest is in full swing now, with no sign of downy mildew.
Zucchini yields
have been good. There are no signs of
any viruses, and I have yet to catch a soybean aphid in my suction trap in
The winter squash crop has generally not been irrigated in our area, and the leaves have really wilted in the last week. No sign of any disease beyond a little angular leaf spot.
Pumpkins in some of fields are irrigated, but the majority are not, so we are seeing wilting here also. No sign of powdery mildew, and the crop is generally advanced over last year.
In sweet corn, European corn borers seem to be non-existent, and we are only catching an occasional corn earworm moth.
The snap beans crop looks pretty good, even where it is not irrigated. Hopefully the heat will be over by the time blossom set begins.
Jim Breinling
The dry weather pattern for July persists along with above
normal temperatures during the past week. Although there have been reports of
isolated storms, there has only been 0.01 inch of rainfall recorded at the
Ludington MAWN station (
Carrot fields in the area are highly variable due to the extreme weather conditions of high winds, high temperatures and lack of rainfall. Even though aster leafhopper counts are generally low and vary from field to field, the visual incidence of aster yellows seems to be higher than expected.
The hot temperatures are resulting in extreme daytime wilting in the winter squash fields for processing, both Butternut and Hubbard types. It will be interesting to monitor fields for fruit size development and yields if current conditions persist.
Snap bean fields
continue to do well. Where available, irrigation systems are running. The European
corn borer traps were moved yesterday, July 31, at the
Sweet corn
harvest in the area continues with good quality. The corn earworm trap counts
for the
Hannah Stevens
Temperatures have been moderate this week, but there has been no precipitation as far as I know. Accumulated precipitation was variable throughout the region in July with accumulations ranging from 0.1 to 2.5 inches. Waterways and pond water levels are very low. It is fair to say that quality and quantity crop losses are happening in non-irrigated fields and there are concerns about winter squash and other fall crops.
Sweet corn harvest is now in full swing. European corn borer trap catches were at their lowest levels for the season with an average of two per trap. No corn earworms have been caught yet. Some bird damage is evident on varieties with loose husks or poor tip cover. Corn borers seemed to have been controlled well.
Pepper harvest continues, and quality and quantity is good on plasticulture fields.
Muskmelon harvest is now underway with watermelons to follow shortly. Some powdery mildew has been reported on pumpkins.
Onions and carrots on muck ground continue to size slowly. Carrot harvest is delayed until next week as growers irrigate to help in sizing. Onion thrips are under control in protected fields.
A field day to view and sample sweet corn varieties will be held on August 23 in the Romeo area. More details will follow.
Paul Marks
We are now at 1761 degree days base 50, which is about four
calendar days behind a long term normal for this date, and catching up several
days this week with the heat. Rain late
last week provided from just less than one inch, to more than four inches in various
parts of
Sweet corn harvest continues. Fields are maturing at a rapid pace under this week’s heat. So far, the market has kept up with supply. Corn borer and earworm numbers continue to be very low in my traps again this week.
Market tomatoes appear to be ripening slower that anticipated with some blossom end rot evident. Bacterial diseases are present in many plantings.
Processing tomatoes for early harvest are just receiving the first applications of Ethrel. Blossom end rot and bacterial diseases are in this crop as well. Fruit load looks good, but size may be less than normal in non-irrigated fields.
Potatoes are being harvested and packed for market with tubers more mature this week. Very little disease pressure and no insects in this crop.
Melons, both muskmelons and watermelons are now being harvested. Size has been good, and very few problems in either of these crops. Some bacterial wilt now evident in muskmelons.
Pepper harvest continues with good bell sizes and yields for this early in the season. Bananas for processing have just begun this week. I have not seen any aphids in this crop.
Pumpkins are now showing fruit in most fields with no downy mildew seen in this crop. Powdery mildew has just begun to show up in several fields this week. Adult squash vine borer and squash bugs continue to be active. I have seen very little virus in this crop.
Cabbage planting for late season harvest has been a challenge with high temperatures and dry conditions over the last several weeks. Recent rains have dramatically improved these late plantings.
Jeff
Andresen
Agricultural Meteorology
Geography
Scattered showers and thunderstorms brought some much needed
rainfall to a few locations across
As was the case last week, medium range forecast guidance
generally suggests a continuation of the current upper air pattern. Some of the guidance does suggest a more west
to east zonal pattern across the
In the medium range time frame, both 6-10 day and 8-14 day
outlooks, covering August 6-10 and August 8-14, call for a continuation of
above normal temperatures state- and region-wide. Precipitation totals are
forecast to range from near to below normal levels across southeastern sections
of the state to near or above normal levels across western sections of the