VegNet Vol. 14,
No. 25.
Ohio
State University Extension Vegetable Crops
On the WEB at: http://vegnet.osu.edu
In This Issue
1. Phytophthora and irrigation water
2. Produce Safety at the Farm Market-A Guide for Farmers and
Sellers
3. Crop Reports
Phytophthora and irrigation water by Mary
Hausbeck, MSU Plant Pathology. From: MSU Vegetable
Crop Advisory Team Alert newsletter. Vol. 22, No. 15, August 8, 2007
Many Michigan vegetable crops such as squash, cucumber, eggplant, pepper,
beans, watermelon, melon and tomato are susceptible to Phytophthora capsici.
This pathogen causes disease on plant crowns, roots and fruit. Phytophthora can
move in surface water, which is often relied upon for irrigation in
In standing water, Phytophthora produces swimming spores which can be spread
with moving water. Swimming spores can survive and cause infection for 8 to 10
hours. Therefore, when surface water is contaminated with Phytophthora, the
pathogen can be spread to a field through irrigation.
Pear and cucumber baits, along with temperature sensors, were placed in plastic
milk crates kept afloat by attaching polyethylene foam pool noodles to the lid.
Floating the baits was important because swimming spores always move to the
surface of the water.
The crates were then suspended in the water for three to seven days before
baits were removed for examination.
Pieces of infected pear and cucumber baits were placed onto media plates which
promote Phytophthora growth. After three days, the plates were examined for Phytophthora.
Some of the Phytophthora collected from surface water was found to be resistant
to the fungicide mefenoxam (Ridomil).
Phytophthora was detected in several surface water sources in multiple years,
even when non-host crops were planted nearby. Most of the infestations occurred
when the water temperature was between 59°F and 77°F.
It is important to take precautions when irrigating crops. If irrigation is
necessary, do not use surface water sources. Drip irrigation from well water or
ponds fed by well water is recommended to reduce the risk of Phytophthora
spread on susceptible vegetable crops. Irrigate conservatively, and try to
limit irrigation close to harvest.
Produce
Safety at the Farm Market-A Guide for Farmers and Sellers by Sanja Ilic & Jeff LeJeune, Food Animal Health Research Program and Doug Doohan, Department of Horticulture & Crop Science.
Consumers don't come to farmers' markets to get a dose of E. coli
or salmonella. But if farm markets turn out to be a source of these or other
causes of foodborne illness, consumers will quickly
choose to get their fresh produce elsewhere.
The Centers for Disease Control and Prevention estimates that 76
million Americans a year suffer a case of foodborne
illness, although many mild cases go undiagnosed. Thousands of cases are more
serious, though: According to the CDC, "there are 325,000 hospitalizations
and 5,000 deaths related to foodborne diseases each
year. The most severe cases tend to occur in the very old, the very young,
those who have an illness already that reduces their immune system function,
and in healthy people exposed to a very high dose of an organism." In
other words, every customer at your farm market is a potential victim of foodborne disease. The safety precautions you take could
save a life, and your business.
Food safety experts with Ohio State University Extension and the
Ohio Agricultural Research and
These are especially important guidelines when handling fresh
produce, much of which will be eaten raw. Other types of fresh food, such as
meat and poultry, are usually thoroughly cooked before eaten, so any
microorganisms they harbor are killed. That's why foods that are not typically
cooked before being consumed deserve special handling.
Remember: Bacteria that cause foodborne
illness can show up anywhere. Even if you grow your goods organically or have a
small operation with just family members involved, your product is as much at
risk as in a large operation. It's just common sense -- and good business sense
-- to take all precautions possible to prevent the foods you sell from becoming
contaminated. Here are some guidelines:
Transportation: • Be
sure to transport food in containers that can be wrapped, covered and otherwise
protected from contamination, and that can be cleaned and sanitized before each
use. Plastic bins would be an ideal choice; don't use wooden crates or used
cardboard boxes, which might harbor disease-causing bacteria and pass it along
to the food items inside.
• Keep produce cold by putting it on ice
or refrigerating it during shipping. Spinach and other leafy greens
should have ice between layers of leaves to keep it cold. Cold
temperatures (below 40 degrees) slows down the growth of microorganisms
and prolongs shelf life.
• Make sure the vehicles you are using to transport food
items are clean. Vehicles that are used to carry fresh produce should not be
used for other purposes that might lead to contamination -- moving animals,
chemicals, or compostable materials, and they should
be free of foreign substances such as bird droppings. Don't
transport produce with raw meat, equipment or gas containers in the same
vehicle -- the chance of contaminating your fresh produce is too great.
Product
Handling: Believe it or not, the simple precaution of washing your hands
often is one of the most effective ways to prevent food contamination.
Wash
your hands:
When
• Before handling produce.
• After every visit to the washroom.
• After a break or meal.
• After hand-to-face contact (e.g., coughing, sneezing, blowing
nose).
• After handling any materials other than the produce (crates and
especially money).
How
• Use proper hand washing techniques.
• Wet hands, lather soap for 20 seconds (sing "Happy
Birthday" twice).
• Scrub well (especially fingernails and knuckles) Use fingernail
brushes if available.
• Rinse
• Dry hands and wrists with paper towel.
If there is no water?
• Use hand wipes to remove soil.
• Use hand sanitizer.
• Do not handle or sell any type of food if you have a
contagious illness -- especially an intestinal problem. If you have any cuts,
sores or wounds, be certain they are bandaged properly. This protects both you
and the food products you are handling.
• Wear clean, protective clothing, such as clean or one-use
aprons, gloves, smocks and shoes. Soiled clothing can harbor bacteria that can
be transferred to produce you're handling.
• Clean and sanitize all utensils and surfaces that will have
contact with food.
• Be sure clean and sanitize all surfaces before setting up
your display. Wipe down surfaces regularly thereafter with a clean towel or
wipe.
• Never allow animals near your produce, including rodents,
birds and domestic pets.
• Pre-pack food items before putting them out for display.
This will prevent too many consumers from handling the same produce, and
protect the produce from dust, dirt, etc. Mark the date clearly on
labels.
• As much as we all like it, money can be pretty dirty!
Consider having one person handle the produce, and another taking money and
giving change . Or, change gloves after handling money
and before handling produce.
• Keep all food items and containers off of the floor or
ground. Containers should be put on a pallet or another empty crate to prevent
dirt, dust or splashing water from contaminating the produce inside, and to keep
rodents or pets from getting into them.
• Separate different types of food, especially high-risk
items such as meat from produce.
• Be sure to have an appropriate waste container nearby, so waste
products can be safely thrown away. Waste containers should be leak- and pest-proof. Containers such as a crate or open
basket could allow leaking and attract pests.
• Educate your customers about food safety and provide hand
sanitizer or wipes for them to use before handling any of your produce.
Crop
Reports by
Ron Becker and
Brad Bergefurd
With heavy rains having occurred in some parts of the county in
each of the last two weeks, some fields of vine crops are showing severe signs
of both pythium and phytophthora
blight. Downy mildew continues to spread to more farms, especially in
cucumbers. Powdery mildew is being found everywhere, including on young
plantings. Cucumber beetles and corn rootworm adults have started feeding
on ripening melons as well as the fruit of other vine crops. Both
European corn borer and corn earworm trap catches increased this week, putting
area sweet corn growers on 4-5 day spray schedules for their silking corn. Fall armyworm damage is also
being found in several sweet corn fields. So far they have been feeding
only in the tassel area.
Hot and dry was the general pattern across the southern
Many pumpkin fields transplanted or direct seeded the mid to end of May are 70
to 90% orange with nice fruit size, this has growers concerned especially with
the continued heavy Powdery Mildew and Downy Mildew disease pressure that continues
to plaque all vine crops. Growers who have not begun their fungicide protectant programs on all
vine crops are experiencing severe economic damage and losses from these
diseases including sun burn on fruit . Growers who are keeping their vines free
of disease and still have good leaf canopy, this is protecting the fruit from
sunburn, those with poor leaf canopy are reporting severe sunburn on pumpkins,
watermelon, cucumbers, summer squash and cantaloupe. Yellow vine decline has
shown up in pumpkin fields with high populations of squash bug which vectors
the disease. The disease takes at least 28 days until symptoms are seen. At
several farm visits and Field Days last month we found high numbers of Squash
bug and squash bug egg masses. To view a Powerpoint
presentation on Yellow Vine Decline see the Veg Net
web site at http://ohioline.osu.edu/~vegnet/problem/yellowv.ppt
Harvest of all summer produce continues with tomato, cantaloupe and sweet corn
harvest peaking this week. Cantaloupe ripening has been enhanced by the high
heat however the normal "glut" has not really occurred and prices
remain above normal for this time of the year with high volumes and numbers
coming through the Bainbridge Produce Auction last week. Marketers are
complaining of slow traffic and slow sales this past week in retail farm
markets and Farmers Markets due to the high heat and traditional "Back to
School" preparation with last minute vacations etc. that always occur from
beginning to mid August. Field seedings of summer squash, pickles, green beans and snap peas,
many as double crops following a previous crop were made this week.
Transplanting of broccoli and cauliflower continues.
Bacterial canker continues to appear in tomato fields. Many growers who have
experienced this disease either bought their plants from greenhouse growers or
else grew their own tomato plants near or in the same greenhouse with garden
varieties of tomatoes that had been grown for bedding plant sales. This
brings us back to the old message DO NOT GROW COMMERCIAL VEGETABLE TRANSPLANTS
NEAR OR IN THE SAME GREENHOUSE WHERE BEDDING PLANTS ARE BEING GROWN!! It
appears to be most severe where growers did not begin a copper fungicide program
soon after planting. It is recommended to begin a fixed copper spray program
soon after transplanting of tomatoes http://ohioline.osu.edu/b672/pdf/Tomatoes.pdf
which may help with control of bacterial disease. For more on this devastating
disease of tomato see the Ohioline fact sheet at http://ohioline.osu.edu/hyg-fact/3000/3120.html