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2007 Epidemic history

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Cucurbit Downy Mildew Epidemic Updates for 2007

 

November 1, 2007

No new outbreaks or updates reported.

 

October 30

No new outbreaks or updates reported.

 

October 25

Georgia - Downy mildew was originally observed on multiple plantings of cucumber in two GA counties near September 20. 90-100 acres of cucumber are infected in Tattnall County (southeast GA). Another 250-300 acres are showing about 40% incidence in Dodge County in south-central GA, near the Telfair County line.

 

October 23

Florida - Downy mildew was confirmed and reported within the last two days in Hillsborough County in west-central FL. A 20 acre field of cucumber is exhibiting about 1% disease incidence. This infection is of recent origin.

 

October 18

Louisiana - Downy mildew has been observed on butternut squash in a home garden in Terrebonne Parish. Disease is suspected to have been present since some time in September.

 

October 16

Florida - About 25% of a 40-acre field of pickling cucumbers is infected with downy mildew. This outbreak, in Lafayette County, is of recent origin.

 

October 2 -11

No new outbreaks or updates reported.

 

 

September 27

South Carolina - Tony Keinath reports that downy mildew has been confirmed in Charleston County on various cucurbits, including watermelon. The watermelon planting is a 60 acre field that is estimated to be 10% infected. Sporulation on the leaves is very heavy. Other cucurbits affected in the area include cucumber, melon, squash and gourds.

Oklahoma - John Damicone reports that downy mildew is present on watermelon in Payne County (Stillwater), OK. The small research plot is 100% infected.

 

September 25

South Carolina - Downy mildew has been reported in Lexington County on cucumber. The 15 acre planting is said to be 75% infected. Downy mildew has also been confirmed in Saluda County on slicing cucumber, summer squash and butternut squash. It has been reported that downy mildew has been infecting cucurbits in the region since mid to late August.

Texas - Tom Isakeit reports that downy mildew is still "raging" in Waller County on watermelon. A cantaloupe sample was confirmed with downy mildew from Eastland County.

 

September 20

Downy mildew has been reported on cucumbers in Scotland County, NC near Laurinburg. Incidence is nearing 100% as cooler temperatures, cloudy skies and drizzle enter the area. Disease has most likely been present for a few weeks; however, hot and dry conditions have held it back. Grower sprayed Tanos approximately one week ago and followed up with Gavel earlier this week. Megan Kennelly also reports downy mildew on cucumber in Johnson County, KS. A one acre planting is estimated to be 100% infected - nearly every plant had lesions, and some leaves are heavily infested. The cucumbers are growing in a high tunnel at the K-State Horticulture Research Center just west of Olathe, KS.

 

September 18

David Langston has reported downy mildew on cucumber in Tifton, GA. The level of infection is very low - estimated as less than 1% of a 0.2 acre plot. A nearby field was also reported as having very early symptoms. Downy mildew was confirmed microscopically.

 

September 13

Michigan - There is a total of 24 counties in MI where downy mildew has been confirmed. The latest reports come from Genesee, Alpena, Montmorency and Newaygo County. All reports are on cucumber with the exception of Montmorency County where downy mildew is present on cucumber and cantaloupe.

 

September 11

North Carolina - Downy mildew has been confirmed on cucumber 'Vlaspik' in Halifax County, NC. Downy mildew is estimated at 35% of the 32 acre planting. This field is sprinkle irrigated and is located in SW Halifax County near Highway 4 and Glenview. Bravo and Tanos have been applied.

 

September 6

North Carolina - Downy mildew has been confirmed on cucumber in Pender County, NC. Squash in the same field did not show symptoms of downy mildew.

New Jersey - Downy mildew was confirmed on pumpkin and Asian melon in Cumberland County, NJ. Andy Wyenandt reports that infection is light in his pumpkin field trials and is widespread on cucumber in southern NJ.

 

September 4

North Carolina - Downy mildew has been confirmed on cucumber in western NC in Haywood (near Bethel) and Henderson (near Dana) Counties. Both are smaller plantings, 2.5 and 8 acres, respectively. The infections are at very early stages of development. Both growers are spraying fungicides, Bravo and Previcur Flex and Tanos, for control. The Haywood County outbreak is on cucumber variety 'Dasher II'.

 

August 30

Michigan - Mary Hausbeck reports on her website that downy mildew has been confirmed on cucumber in Muskegon and Mecosta Counties. Downy mildew has also been confirmed on gourd and zucchini in Monroe County, as well as cantaloupe in Montcalm County.

 

August 28

New Hampshire - Downy mildew has been reported in Hillsborough County, NH near Litchfield. Two fields with 2 and 4 acres of cucumbers have been reported as 100% infected. The cucumber plantings are of varieties 'Regan' and 'Marketmore'. Copper, chlorothalonil and azoxystrobin have been applied. Additional fields have been reported with symptoms by the UNH Cooperative Extension County Educator.

Pennsylvania - Downy mildew has been confirmed on cucumber and cantaloupe in Lycoming County, PA near Williamsport. The half acre planting is described as 55% infected. Copper and chlorothalonil have been applied.

 

August 23

Michigan - Downy mildew has now been confirmed on cucumber in a total of 18 counties in MI. The latest counties include Jackson, Cass, Berrien, Ionia, Montcalm and St. Joseph.

 

August 21

North Carolina - Downy mildew has been confirmed on cucumbers in both Rowan and Alamance Counties, NC. The source in Rowan County is a 2-acre field that is reported as 5% infected. Little rain has fallen in this area, but early symptoms are developing. More information from the Alamance County source to come soon.

Virginia - Steve Rideout has reported downy mildew on cucumbers in Northampton County, VA near Cape Charles. The 35 acre field is reported as being 5% infected. The grower has sprayed chlorothalonil for control.

Missouri - Simeon Wright has confirmed downy mildew on pumpkin in Pike County, MO near Annada. The sample was taken from a field that has been described as 25% infected.

 

August 16

Downy mildew has been confirmed in Worcester County, MA. A 1/4-acre field of cucumber is 80% infected. Symptoms appeared within the last week. Two commercial fields in Suffolk County, NY (Long Island) have confirmed disease. One small field (1-2 acres) of gourd and pumpkin is affected, as is another 10-acre field of cucumber. Downy mildew is in single spots in each field, with both older and newer lesions present. These 2 new outbreaks are being combined with the existing sources in southern New England. We have our first report of downy mildew from southern Quebec, near the city of Montreal. A 3-acre field of cucumber is showing about a 1% incidence. This source will be combined with the western NY / southern Ontario sources. Confirmation is in concerning the presence of downy mildew in Cumberland County, PA. Several farms near the Shippensburg area have had disease affect primarily their watermelon crop during the first part of July. The Epidemic Status map has been updated to reflect the confirmation, but we will not add this area to the forecast rotation until we can determine whether or not disease is still active.

 

August 14

Texas - More than 1000 acres of cucumbers in the panhandle of TX have been reported to have downy mildew. A 120 acre field in Hale County (near Hale Center) is said to be 100% infected. The yield from infected planting is said to be reduced from 280 bushels per acre to 30-50 bushels per acre.

Michigan - Mary Hausbeck and MSU's VegCAT has reported downy mildew on cucumber in a few more counties in MI. Cucumber fields in Arenac, Macomb, Clinton and Ingham Counties have been identified with downy mildew.

Massachusetts - A 2-acre cucumber field in Plymouth County, located in the eastern part of MA, has been reported as 100% infected with downy mildew. All plants were killed and yield was zero.

Connecticut - Downy mildew was found on 4 cucumber varieties in the All-American Selection trial garden at the University of Connecticut Plant Science Research farm in Tolland County. Other cucurbits, including winter squash and pumpkins, growing nearby do not have downy mildew. One of the 6 varieties of watermelon is exhibiting some symptoms.

 

August 9

Texas - Tom Isakeit reports that there is no longer an active source of downy mildew in Hidalgo County, TX. The 'hot spot' in the state is west TX and the High Plains.

Michigan - On a recent visit to MI, Tony Keinath reports the presence of downy mildew on cucumber in Tuscola and Wayne Counties. The Tuscola County source is a 13 acre field reported to be 1% infected. This field will be harvested within two weeks. The Wayne County source is a home garden with 25% infection. Though this is not a significant source, it is important to note the occurrence in this new county.

New Jersey - Andy Wyenandt has reported downy mildew on cucumber in a 3-4 acre field in Gloucester County, NJ near east Vineland. The field is said to be 30% infected. The grower has been applying fungicides for 3 weeks.

Massachusetts - A report of downy mildew on cucumber has come out of Bristol County, MA near Westport. Bristol County is located in southeastern MA and borders RI. The half acre, organic field is said to be 50% infected.

 

August 7

Texas and Oklahoma - A new report of downy mildew on watermelon has come from Tom Isakeit in TX. The 50 acre watermelon field in Glasscock County (near Garden City) TX is said to be 40% infected. Recent moderate temperatures and moist conditions have encouraged disease progression. Moderate to heavy disease has also been reported in a 75 acre field in Jefferson County, OK. Host is not known at this time. The field has been harvested and the disease has likely been there for some time. More information to be reported as it is received.

Delmarva Peninsula - Kate Everts reports downy mildew on cucumber in three counties in MD. Caroline and Dorchester Counties, MD are reporting disease at low levels. In Wicomico County infection is slightly more serious in an experimental plot. Sussex County, DE has also reported disease at low levels.

North Carolina - Downy mildew has been confirmed in a small plot on an NC State Experiment Station in Johnston County, NC. The downy mildew has been confirmed on cucumber and cantaloupe at high levels and honeydew, bitter melon, and squash at very low levels.

Louisiana - Downy mildew has been reported in DeRidder, Beauregard Parish, on watermelon. Five fields have been positively identified with the disease; each is 20 acres or less. Some of these fields have been totally lost due to downy mildew.

 

August 2

Two new outbreaks have been reported. Moderate to heavy disease activity was discovered in Jefferson County, OK in 75 acres of fields just before harvest. Disease has been present for some time, but just how long is uncertain. Incidence was near 100%. Downy mildew was also spotted recently in Jasper County, MO in a field that has now been harvested. Details are unavailable for this find. The fate of these fields ... whether they have been left 'as is', disked under, etc. is unknown at this time.

 

July 31

Downy mildew has been confirmed on pumpkin in Mason County, IL. 80% of a combined 100+ acre area is infected, with heavy sporulation. Benny Bruton reports downy mildew in Upton County, TX (50% of a 100-acre field) and Waller County, TX (25% of a 50-acre field). Upton County is in western TX west of San Angelo and will be included in the revamped forecasts. Recent weather has been favorable in the southern High Plains of TX. Most of a 0.1 acre field in Orleans County, NY near Brockport is also infected with downy mildew. Reports indicate that control products are being used in most of these locations. We have already had previous reports from Waller County, TX and Orleans County, NY. Also, we have received word that Victoria County, TX is no longer a source of downy mildew. Indications are that more reports of downy mildew will arriving later this week.

 

July 26

Texas - Tom Isakeit reports downy mildew on cantaloupe at a small commercial vegetable farm in Tom Green County, TX. The field is about a tenth of an acre with 30% infected. Downy mildew was not found on watermelon in the same vicinity.

Michigan - According to the latest edition of MSU's Vegetable CAT Alert, downy mildew has been confirmed on cucumber in there new sites in MI: Saginaw County, Bay County, and a fourth site in Monroe County.

 

July 24

Missouri - Simeon Wright reports that downy mildew has been confirmed in Platte County. Details of the outbreak will be available soon.

New York - Chris Smart has confirmed downy mildew on cucumbers in Monroe County, NY near Brockport where at least two fields were found to have symptomatic leaves. At least three fields in Orleans County have been identified as having downy mildew. Growers are rotating chemistries to control the pathogen.

Sampson County, NC - Downy mildew has now been confirmed on watermelon in one approximately 10-acre field.

 

July 19

The new issue of MSU's Vegetable CAT Alert has reported that downy mildew has been confirmed on cucumber in Lenawee County, MI. Lenawee County is located directly west of Monroe County and so has been combined with this source for forecasting purposes.

 

July 17

No new outbreaks or updates reported.

 

July 12

Mary Hausbeck has confirmed downy mildew in a commercial cucumber field in Gratiot County, MI. Steve Rideout has reported downy mildew on old squash and cucumber plants in Virginia Beach, VA. The 2-acre field is reported as 25% infected. David Langston has reported that downy mildew is finally in Tifton, GA. The downy mildew was found on sentinel plants of cucumber, melon, and squash to varying degrees. This is a plot that is approximately a quarter of an acre and is 50% infected. Because this source is small, the threat and risk associated with its transport events have been adjusted appropriately.

 

July 10

Sally Miller reports that downy mildew has been confirmed on cantaloupe in Holmes County, OH. The cantaloupe field is adjacent to a cucumber field that had been seriously infected with downy mildew. This cucumber field has been plowed under. Sporulation is reported as relatively sparse. Holmes County is located just south of our Medina County source. Downy mildew has been reported in Norfolk County, Ontario, Canada. The 10-acre cucumber field is reported as 60% infected. Though weather conditions have been hot and dry in this area, a significant rain occurred on July 3. Symptoms were confirmed on July 6. Norfolk County is located just east of our Aylmer (Elgin County) Ontario source.

 

July 10

New Reports from MD, OH, and NC: CDM has been confirmed in various fields of cucumber in Dorchester County, MD. These fields and others are spread across Dorchester and Caroline Counties, totaling approx. 300 acres. Incidence is at 100%, severity at 10%. Estimated first date of symptoms is June 30. CDM has been confirmed in Sandusky and Ottawa Counties, OH. Multiple fields spread across these 2 counties are infected, totaling 100 acres of pickling cucumber. Incidence is 40% and severity is 25%. Estimated first symptom date is June 30. CDM is on cucumber in a research plot in Pitt County, NC. Incidence is 100% and severity is 25%. Estimated first date of symptoms is June 30. There was also epidemic spread reported from previously infected sentinel plots in several other NC counties.

 

July 5

No new outbreaks or updates reported.

 

July 3

North Carolina - Downy mildew has been confirmed on more cucumbers in Sampson County, NC in Clinton on the Horticultural Crops Research station. The infected area is about 10' x 20' m and disease is becoming severe on cucumbers affected. Downy mildew has also been confirmed on cantaloupes in Sampson County, near Suttontown. This 25 acre field is approximately 40% infected. Hot spots in the field have completely 'melted'.

South Carolina - Tony Keinath reports a small field of cucumbers with downy mildew in Beaufort County, SC (near Frogmore). A scout reported the downy mildew on 23 June, confirmed on 2 July.

 

June 29

Downy mildew was confirmed on cucumber samples from SC late Thursday evening. The samples were found by a contractor in Williamsburg, Horry, Clarendon, and Florence Counties. These fields were described as 50% infected. More details will be available as we receive them.

 

June 28

There have been many outbreaks reported over the last few days.

Falls County, TX (Highbank) - downy mildew has been identified on watermelons. The field is quite saturated from the heavy showers in TX over the past two weeks and though there are heavily necrotic areas in the field, young lesions are present.

Elgin County, Ontario, Canada (Aylmer) - A 1-acre field of fresh market cucumbers grown under row covers is reported as having 100% downy mildew incidence. This planting is from transplants grown in a dedicated transplant greenhouse that was vacant in the winter months.

Eastern NC, Sampson and Bertie Counties (Spivey's Corner and Windsor) - A group of seed company representatives touring fields found downy mildew in 5 out of 6 fields in the Bertie County area. In Sampson County varying degrees (5-85% incidence) of downy mildew was found in 7 out of 8 fields. This area has been very dry over the past few weeks. Most fields are under serious drought stress, though downy mildew is still present. No fungicides have been applied as of yet.

 

June 26

Ontario County, NY (Geneva) - Downy mildew has been confirmed on cucumber plants in an educational garden at a local school. Symptomatic plants were removed and the remaining plants are being inspected daily for downy mildew. Though this seems to be a weak source, it is likely that nearby plantings are infected.

Waller County, TX (near Hempstead) - Tom Isakeit has reported a 43 acre watermelon field as being 2% infected with downy mildew. The grower has apparently had a problem for about a month; however aggressive fungicide applications paired with dry weather had reduced symptoms in early June.

Erie County, OH (Milan) - Sally Miller has reported that downy mildew has been confirmed on cucumber from a small 1-acre farm in Milan, OH. This field has not been treated with fungicides and is said to be 5% infected.

Duplin county, NC (Albertson area) - Allan Thornton has confirmed downy mildew on cucumbers from a 25 acre farm in eastern NC. The field is said to be 95% affected by downy mildew. Such a large area suggests that this source has been established for at least a few weeks. This is surprising as the area is very dry and no irrigation has been used.

Monroe County, MI - Mary Hausbeck has confirmed downy mildew on cucumber from both a small farm (less than 1 acre) and a 10 acre farm in Monroe County. It is thought that disease in the 10-acre farm has been established for 10-14 days.

 

June 21

Dr. Sally Miller from Ohio State has reported downy mildew on cucumbers in Medina County, OH. The outbreak was confirmed on June 20, and is said to affect 20% of a cucumber field. The size of this field is unknown at this time. None of the eleven other farms scouted in the area appear to be affected. More information will be provided as we receive it.

 

June 14 - 19

No new outbreaks or updates reported.

 

June 12

Dr. Mary Hausbeck has confirmed that there is downy mildew on greenhouse cucumbers in Essex County, Ontario, Canada. Dr. Hausbeck explains that these are "not plug plants for field production but are 'hothouse' cucumbers". Essex County is Canada's southernmost county located on a peninsula of land that juts out into the Midwestern U.S. No field outbreaks have been reported in Canada or Michigan. More info will be reported as we receive it.

 

May 24 - June 7

No new outbreaks or updates reported.

 

May 22

Downy mildew has been reported on cantaloupe in Victoria County, TX. The source is a one acre field that Tom Isakeit reports as 40% infected. Squash and watermelon in the field do not appear to be affected. Due to the proximity of the two sources in TX, they will be combined for the purposes of the forecasts.

 

May 15 - 17

No new outbreaks or updates reported.

 

May 10

Our thanks to Gene McAvoy, who informs us that while production is winding down around Florida's southeast coast, some disease is still present on squash and cucumber. Given that we are nearing the end of the cucurbit growing season in that area.  We are combining the southern FL source areas into one source region. Posted transport events will start from Immokalee, but the remaining infections in southeast FL are still being included in the forecast analysis and risk prediction.

 

May 8

Downy mildew continues to be a problem around Immokalee. Incidence is on the increase. Cantaloupes, cucumbers, and squash are being affected. Downy mildew is also present in scattered areas on watermelon. Incidence is high in some locations.

 

May 3

Downy mildew has been reported on watermelon in Hidalgo County, TX. Details are sparse. Disease was observed as 'hot spots' in one field and was also observed in another field a few miles away. This source is most likely weak.

 

April 17 - May 1

No new outbreaks or updates reported.

 

April 12

No new outbreaks have been reported. Recent info from Gene McAvoy in southern FL indicates the following: Downy mildew continues to be a problem on cucumbers and squash around Immokalee. Disease has reached moderate to high levels in some older fields. Organic growers experiencing difficulty achieving control and yields are limited in some cases. On the East Coast, downy mildew continues to affect cucumbers and squash, especially around older, infected plantings. Around Homestead, reports indicate high levels of downy mildew on cucumbers and melons.

 

March 6 - April 10

No new outbreaks or updates reported.

 

March 1

Reports from southern Florida indicate that downy mildew is present near Immokalee (Collier County), on the eastern coast (Palm Beach County), and in the vicinity of Homestead (Dade County). Cucumber and squash are being affected around Immokalee with disease reaching moderate to high levels in some older fields. Downy mildew is affecting cucumber plants near the 2-3 leaf stage near the east coast. Incidence and severity are heavy in some locations. Cucumbers and melons are being affected near Homestead.