ISSN 2291-6121
HORT MATTERS
OMAFRA Specialists in Horticulture and Specialty Crops.
VOLUME NO. 16, ISSUE NO. 7
June 16, 2016
Thinking of trying interseeding?
There has been significant interest in interseeding cover crops into field corn this
year. The same possibility holds for sweet corn with the similar risks and challenges.
Tips for interseeding:
IN THIS ISSUE...
 Hort Shorts
 SWD Update
 Cucumber downy
mildew update
 Hops workshops
 Get ready for
summer - cover
crops
 Nutrient deficiency
refresher
 Do you want to
increase crop
yields and reduce
soil erosion?
HORT MATTERS

Broadcast or plant the cover crop when corn is at 4-6 leaf stage. Broadcast
application is fast but leaves the seed on the soil. Some growers are trying to
achieve more incorporation and soil contact to even out stands.

Timing is important – the cover crop needs a bit of time to establish before the
rows close and the soil is heavily shaded by the crop.

Consider the herbicide program when selecting the cover crop. Check out
fieldcropnews.com/category/cover-crops/ for a current research summary on
herbicide impacts on annual ryegrass and clover

Annual ryegrass is the most herbicide tolerant and summer drought tolerant
(it will go dormant) making it often a better choice but have a plan in place for
controlling the annual ryegrass prior to the next crop.
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June 16, 2016
OMAFRA STAFF
working for you
Horticulture Technology
Mike Celetti
Plant Pathologist
Jim Chaput
Minor Use Coordinator
Hannah Fraser
Entomologist
Mackenzie Lespérance Weed Management (A)
Christoph Kessel Nutrition
Deanna Németh
Nutrient Management Planning Spec.
Anne Verhallen
Soil Management Specialist
Denise Beaton
Crop Protection Program Lead
Jason Deveau
Application Technology Specialist
COMING EVENTS
519-824-4120, x58910
519-826-3539
519-824-4120, x52671
519-738-1232
519-824-4120, x52480
905-562-1170
519-674-1614
519-826-6594
519-426-8934
Horticulture Crops
Vacant
Vegetable Crops Specialist
519-826-3678
Wendy McFadden-Smith Tender Fruit & Grape IPM Spec. 905-562-3833
Jennifer DeEll
Fresh Market Quality
519-426-1408
Pam Fisher
Berry Crop Specialist
519-426-2238
Janice LeBoeuf
Vegetable Crops Specialist
519-674-1699
Elaine Roddy
Vegetable Crops Specialist
519-674-1616
Kathryn Carter
Tender Fruit & Grape Specialist
905-562-1639
Amanda Green
Tree Fruit Specialist
519-426-1102
Kristy Grigg-McGuffin Pome Fruit IPM Specialist
519-426-4322
Marion Paibomesai Vegetable Crops Specialist
519-826-4963
Greenhouse, Agroforestry & Specialty Crops
Jim Todd
Transition Crops Specialist
Melanie Filotas
Specialty Crops IPM Specialist
Sean Westerveld
Ginseng & Medicinal Herbs Spec.
Evan Elford
New Crop Development Specialist
Chevonne Carlow Greenhouse Floriculture Specialist
Sarah Jandricic
Greenhouse Floriculture IPM Spec.
Shalin Khosla
Greenhouse Vegetable Specialist
Cara McCreary
Greenhouse Vegetable IPM Spec.
Jennifer Llewellyn Nursery & Landscape Specialist
Todd Leuty
Agroforestry Specialist
Mahendra Thimmanagari Crop Bioproducts Specialist
519-426-3823
519-426-4434
519-426-4323
519-426-4509
905-562-4141, x179
905-562-4141, x106
519-738-1257
519-738-1258
519-826-4738
519-826-3215
519 826-4593
www.ontario.ca/crops
Agricultural Information Contact Centre 1-877-424-1300
July 29, MSU Extension annual Hops Field Day and
Tour, 8 a.m. – 5 p.m. Participants will meet at the MSU
Horticultural Research Center (6686 South Center
Highway, Traverse City, MI 49684), board a chartered
bus and travel to various hop yards in the area, visit a
local brewing company for lunch, and additional hop
yards in the afternoon. The cost will include lunch,
charter bus transportation and education/
handouts. Pre-registration is required and space is
limited. Look for registration information on the website
hops.msu.edu in the next couple of weeks.
August 13-17, International Strawberry Symposium,
Quebec City. For more information visit the website at
www.iss2016-quebec.org/en
August 18, North American Strawberry Growers
Association Summer Tour, Quebec. For more info
contact [email protected] or visit the website
www.nasga.org.
August 24, Mark your calendars now for the
Biennial Grape Tailgate Tour to be held from
9:00 a.m-2:00 p.m. More details to follow.
Subscribe on-line to receive notice by email when a new issue of Hort
Matters is posted. All you need to do is enter your email address at
www.omafra.gov.on.ca/english/subscribe/index.html
and submit.
September 1-3, 4th International Pawpaw
Conference, Frankfort, Kentucky. For more information
visit the conference website.
September 13, Ontario Berry Growers Association
Season Wrap-up, Barrie Hill Farms, Barrie. For more
information contact the OBG at
[email protected] or 613-258-4587.
September 13-15, Canada’s Outdoor Show, Woodstock
www.outdoorfarmshow.com/
Edited by:
Hannah Fraser, Entomology Program Lead (Hort)
Prepared by:
Carolyn Prieur, Client Service Rep, Vineland Resource Centre
September 20-24, International Plowing Match,
Harrison (Minto Township) www.plowingmatch.org/
November 4-13, Royal Agricultural Winter Fair,
Exhibition Place, Toronto www.royalfair.org/
Suggestions? We’d like to hear from you
Hort Matters, OMAFRA, Box 8000, 4890 Victoria Avenue N,
Vineland Station, ON L0R 2E0 Ph. 905-562-1674 Fax 905-562-5933
Email: [email protected]
HORT MATTERS
July 19, Ridgetown Open House
For commercial vegetable growers and
agribusiness: mark your calendar for Tuesday, July 19
for the Ridgetown Vegetable Open House, hosted by
OMAFRA and Ridgetown Campus –
University of Guelph
 Ridgetown area — more details to come on times
and tour locations.
 Choose an afternoon or evening tour.
 No cost. No preregistration required.
 Watch for more details soon.
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February 22, 23, 2017, Ontario Fruit & Vegetable
Conference, Niagara Falls www.ofvc.ca
June 16, 2016
HORT SHORTS
Apples: Apples are at fruit set and increasing in size. Thinning applications are finishing up. There was a variable response
to thinners across the province. Some growers experienced hot weather during their thinning window which helped with the
effectiveness. Other growers had their thinning window when the weather turned cooler and found less success with the
chemical thinners.
Berry crops - Soils are again very dry in many parts of Ontario.
Strawberry harvest is underway in southern Ontario, with crop development about a week to 10 days later in eastern
Ontario. Growers are expecting an excellent crop through to early July. There have been several complaints about fruit not
sizing in the variety Annapolis. More advanced plantings of day neutrals are starting to bloom and runner – signaling the
beginning of the next main crop in approximately a month.
Raspberries are in bloom or green fruit stage. Although a good crop seems probable in southern Ontario, winter injury has
been significant in eastern regions.
Blueberries have green fruit are sizing and petal fall sprays have been applied. Harvest in the Simcoe area will begin about
July 7-10. On older branches on some cultivars there is an abundance of green fruit and lack of leaves; this fruit will not
reach maturity.
The first SWD flies were trapped last week, in wild hosts in the earliest regions - Niagara and Harrow.
Ginseng: It is getting very dry in most of the ginseng production area and growers should continually monitor soil moisture
to avoid moisture stress which can lead to more disease issues and poor seed set. Alternaria is the greatest risk under
these dry conditions, but no major outbreaks have been reported.
Lavender: The earliest cultivars of lavender will begin to bloom in the southwest over the next week or two. Four-lined plant
bugs are causing damage to developing stems and are getting closer to the adult stage. Garden fleahoppers are also
increasing in number, but are more patchy. We also caught some twice-stabbed stink bugs in lavender this week, which
can feed on lavender but have not been known to cause significant damage.
SWD UPDATE
June 10 - Traps for SWD are installed at approximately 30 sites across Ontario. This week
was the first week that traps were collected. Although not all samples have been processed,
we have detected the first SWD at two sites, in the early areas of Ontario, in traps collected
June 6-7.
In Essex county near Harrow, and in Niagara Region near Fenwick, we have confirmed a
single SWD female fly at each site. In both cases the traps were placed in wild hosts in
woods or hedgerows, not in crops.
These early areas are typically our first sites for SWD, and typically we find a few flies in wild hosts for a week or so
before they move into crops. However, in Niagara and Essex regions, and other very early areas, SWD may begin to
build up. Sweet cherries and raspberries ripening in greenhouses may be at risk. Strawberries seem less susceptible
early on, but should be harvested frequently and thoroughly.
It is interesting to compare our observations to the
degree day model for SWD that was developed in
Oregon. According to this model, and data published
by Environment Canada for Beamsville and Harrow,
the predicted event “first egg laying by the first
generation of flies” has occurred in these locations.
A list of insecticides registered for SWD control in
fruit crops has been updated for 2016 on the
OMAFRA website.
2016 trapping locations
HORT MATTERS
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June 16, 2016
Cucumber downy mildew update – June 14th, 2016
Elaine Roddy, Vegetable Crop Specialist
To date there have been no confirmed reports of downy
mildew in the Great Lakes region. However, activity does
continue in the Southern US. The ipmPIPE website tracks
the epidemic (figure 1) and also forecasts the potential
spread of the disease.
Historically, downy mildew has arrived in this area in lateJune to early July. We have found that using an early
broad spectrum preventative fungicide program, staring at
vine development, will result in better season long control
of the disease. This is especially important if weather
conditions turn wet and overcast, with storm originating in
the Southern US.
For complete details see the 2016 Downy Mildew Control
Strategy for Cucumber Crops.
Figure1: Cucurbit Downy Mildew Epidemic Status Map, 2016-06-14
If you suspect downy mildew in your cucurbit crop, please notify OMAFRA, your agri-business supplier or your grading
station. Downy mildew is a community disease and open communication is vital to ensuring a healthy crop.
Reminder – Upcoming hops workshops
Just a reminder of two upcoming hops field workshops, in particular the deadline to register for the Hops Informal Field
Workshop is Friday, June 17.
Hops Informal Field Workshop
Pleasant Valley Hops
18683 Loyalist Parkway, Hillier, Prince Edward County, ON
Wednesday, June 22, 2016 (Rain date June 23)
4:00 p.m. - 6:30 p.m.
Melanie Filotas, Specialty Crops IPM Specialist, OMAFRA and
Evan Elford, New Crop Development Specialist, OMAFRA
Join OMAFRA specialists Melanie Filotas and Evan Elford for an in-field workshop on seasonal issues in hops. Topics
covered will include an overview of scouting hops yards, hands-on identification of key pests present in the hops yard
and a discussion of current production challenges of not for the 2016 season. This is an in-formal workshop with ample
time for participants to ask questions on current agronomic and pest management challenges. To register, contact
OMAFRA’s Agriculture Information Contact Centre at 1-877-424-1300. Deadline to register—Friday, June 17.
Hops Sprayer Optimization Workshop
Heritage Hill Hop Yard and Nursery
1933 Line 2 N, Shanty Bay ON
Wednesday, July 20, 2016 (Rain date: July 21)
9:00 am – noon
Jason Deveau, Application Technology Specialist, OMAFRA and
Melanie Filotas, Specialty Crops IPM Specialist, OMAFRA
This in-field workshop is intended for sprayer operators or those planning on spraying hops. Jason Deveau and
Melanie Filotas, OMAFRA will talk about the importance of proper spray coverage in hops and discuss what “good”
spray coverage looks like in hops. Learn how to calibrate your sprayer and adjust settings to match the height of the
plants. To register, contact OMAFRA’s Agriculture Information Contact Centre at 1-877-424-1300. Deadline to
register - Friday, July 17.
HORT MATTERS
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June 16, 2016
Get ready for summer….cover crops
Anne Verhallen, Soil Management Specialist (Hort Crops)
Early harvested vegetable crops offer opportunities to do soil maintenance. Double cropping with vegetables or
soybeans may be attractive financially but do little to rebuild soil structure and maintain organic matter.
June and July options for cover crops:

Pearl millet and sorghum sudan – both are warm season grasses. They have tremendous growth potential and are
relatively drought tolerant. The seed is quite small so plant shallowly preferably with a drill. Both will need some
nitrogen to achieve maximum growth. These plants grow fast under warm conditions so be prepared to mow every 4
to 5 weeks if you want manageable residues, and leave at least 20 cm of growth to ensure regrowth.
Seed pearl millet at 10 kgs/ha. Seed sorghum sudan at 15-30 kgs/ha.

Buckwheat is a very short term cover crop – it does a great job of suppressing weeds. But watch it – it can flower
and set seed within 6 weeks so it needs to be managed. It has a very fine, fragile fibrous root system which will help
to build soil structure. The bees and wild pollinators will love you for planting buckwheat – the flowers are very
attractive, particularly in mid to late summer when little is flowering. Seed at 20 – 30 kgs/ha

Spring cereals like oats and barley will do fine in the summer as long as there is some moisture. They don’t
particularly like the heat but both will put on a lot of biomass in a short time. The fibrous root systems will help to
build soil structure and stabilize the soil. Winter cereals like rye and winter wheat can be planted at this time,
especially for headlands. The winter cereals need cold temperatures to come into head so they will just continue to
thicken and build a root system in the summer and early fall. Seed oats and barley at 20 to 50 kgs/ha.
A dense stand of sorghum sudan does an excellent
job of suppressing weeds
Watch the flowering on
buckwheat; great for pollinators
but you don’t want to get to
seed set.
Oats and the other cereal grains make an
excellent choice for headlands, helping to
protect the field while buffering the soil
from traffic.
..… in the OMAFRA Blogs
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Reminder: Check and Double-check that Haskap Bird Netting
Have Your Say on Northern Agri-Food!
Continued Management of Phytophthora in Lavender
Ginseng Crop Update – June 10, 2016
A Couple of Diseases on Trees
New IPM Database Tool for Ontario
HORT MATTERS
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June 16, 2016
Nutrient deficiency refresher
Chevonne Carlow, Greenhouse Floriculture Specialist
As we start to move into fall and winter crop production cycles, it’s a good time to go back through some basics about
nutrient deficiencies.
No matter where you are in a cropping cycle, nutrition problems can be tricky to figure out. The good thing is that they
can be differentiated from disease or pest issues based on a few key observations:
 If the damage is uniform and crop wide, it’s most likely a nutritional issue
 If the damage is localized or more random, it’s most likely a disease or pest issue
Key indicators of specific nutrient deficiencies are easy to spot with regular monitoring, and should be knowledge that
just needs a refresher every now and then. Key indicators are listed here, along with a handy infographic below.

Nutrient Mobility: When deficient, mobile nutrients will move to the new growth, but immobile nutrients will be
trapped in the old growth. A quick scan of where the damage is occurring can help to narrow the potential culprits.

Stunted growth: If plants are looking shorter than normal crop wide this can be a sign of nitrogen (N) or phosphorus
(P) deficiency, especially if the older growth also looks yellowed. Individual or clustered groups of stunted plants are
more likely to be caused by diseases. Look for small root systems and/or wilted shoots can be a sign of black root
rot (Thielaviopsis) or Pythium.

Interveinal chlorosis: Dark green leaf veins with light green to yellowed leaf tissue? Sounds like a deficiency in
magnesium (Mg), copper (Cu), iron (Fe) or manganese (Mn). Magnesium should present in the bottom leaves first
since it’s a mobile nutrient. Copper, iron and manganese are immobile, so expect to see the chlorosis in the newest
leaves initially. Of course, as the deficiency progresses, you can expect to see it throughout most leaves.

Leaf margins: If a border around the outer edge of a plant’s leaf looks yellow, purple, red or brown it might be a potassium or calcium deficiency. This can also be a sign of pesticide or fungicide phytotoxicity, so review your spray
records carefully.
Figure 1. Common nutrient deficiency indicators for horticulture crops.
HORT MATTERS
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June 16, 2016
Remember, many deficiencies are not as simple as they first appear. Nutrient interactions can be positive (synergistic)
or negative (antagonistic). Synergistic interactions between nutrients can help one or both to have greater uptake by
the plant. Most deficiencies occur because of an antagonistic interaction between nutrients, where they compete
with each other for uptake (Figure 2).
Figure 2. Mulder’s Chart shows positive and
negative interactions between plant nutrients.
The negative interaction can occur in one of two ways. In the first, an excess of one nutrient can block others from
uptake sites on the plant root, making it deficient because it cannot get to an uptake site. In the second, the excess
nutrient is present in high enough amounts that it changes the pH of the growing media, making the other nutrient
unavailable to the plant.
In many cases, one nutrient in excess can knock many others out of balance. For example, an excess of Potassium (K)
can cause (Figure 3):
 Increased availability of Iron (Fe) and Manganese (Mn)
 Decreased availability of Nitrogen (N), Phosphorus (P), Magnesium (Mg), Calcium (Ca), and Boron (B)
Figure 3. Modified Mulder’s Chart for excess potassium. This
decreases the availability, and can result in deficiencies of
nitrogen, potassium, magnesium, calcium and boron.
I’ve got just one more important point for this post. Knowledge of your growing media’s pH is essential to keep
nutrients available to the plant. If you stray too far from the target range for your crop and media, nutrients will get
converted to forms that are not available to the plant, turning your fertilizer solution into very expensive waste! A pH
between 5.5 and 6.0 can also help to keep diseases like black root rot (Thielaviopsis) and Pythium at bay.
References:
 Guide to Greenhouse Floriculture Production, OMAFRA Publication 370.
 More reasons for soil testing. MSU extension.
HORT MATTERS
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June 16, 2016
Do you want to increase crop yields and reduce soil erosion?
Jennifer Jarvis, OMAFRA
Windbreaks can increase crop yields up to 15 per cent, more than making up for the amount of land they use. How?
Windbreaks improve a field’s microclimate by reducing wind speeds, increasing temperatures and reducing the amount
of moisture loss.
Have you considered planting a windbreak? Windbreaks can also:
 reduce soil erosion
 decrease odour and spray drift
 offer alternative income options
 save you up to 30 per cent in heating and energy costs
 shelter livestock from the wind and sun
Graph: Each bar represents yield average, as
studied by the University of Guelph Ridgetown
Campus. Yields increased on the downwind
side of the windbreak over distances of up to
12 times the height of the windbreak. Crop
yield increases vary by crop type. Taken from
Establishing Tree Cover.
What are the costs associated with planting windbreaks?
There are costs when planting a windbreak, such as site preparation, purchasing the trees and planting. Some
conservation authorities in Ontario have cost-share programs that can help you with these costs. Contact your local
conservation authority to see how they can help you plan and plant a windbreak.
What type of windbreak should you plant?
The type of windbreak you plant and how you plant it depends on the purpose for the windbreak.
 One to three rows of trees are most often planted to protect field crops from the wind and to reduce soil erosion.
Multiple row windbreaks often include at least one row of conifers.
 Think about planting at least one row of hardwood trees for future alternative income sources, such as wood for
fence posts, fuel and lumber.
 Plant a shelterbelt (more than three rows of trees) around your home and farm buildings to save on energy costs.
 Plant a conifer windbreak to provide livestock with wind and sun protection.
 Windbreaks deflect odours upward if properly situated to the barn.
 The taller the windbreak, the greater the area it protects. Consider the maximum height of the tree species you
choose and determine if it will provide you with the protection you need.
 Keep in mind the crops that you plan to plant beside the windbreak, and the winter hardiness and typical lifespan of
the selected tree species.
 Some trees may be better suited for areas with tile drains than others, an important, and potentially money-saving,
consideration.
The type of soil of your land and the region of the province you’re in will also affect the type of trees you can plant. Trees
can thrive and provide maximum protection when they’re matched with the right soils. Visit the Ministry of the
Environment and Climate Change’s Tree Atlas to determine the best trees for your situation.
Need help?
For help with planning and planting a windbreak, contact your local conservation authority. They may be able to visit
your planned windbreak site and help you with your planting plan, site preparation, choices of tree species, and
appropriate spacing and planting, as well as windbreak maintenance.
HORT MATTERS
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June 16, 2016