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8.  Vegetable Scouting Report for week of July 10-15-from Cornell
University

 

Sweet Corn

Looking at many corn fields we are finding something that goes against
what we usually find in the field.  European corn borer (ECB) adults
normally fly between the end of May and the middle of June.  After the
flight, because the adults find the most mature corn most attractive,
larvae populations are usually highest in the most mature corn.  The
percentage of ECB worms in later plantings decreases until the second
flight begins in late July.  This summer, we are finding more ECB worms
in the second and third plantings than the first plantings.  I think
this is because of all the rain we had in May and June. We had an up and
down flight where normally the flight peaks and then numbers go down
after that.  This is a guess but in any case, we are seeing higher
percentages of ECB in later corn plantings as we go along.


It is quick and easy to find out how much ECB you have in your fields.
Walk through the field and stop randomly at 5 locations.  Inspect 5
plants at each location for ECB feeding damage - holes, saw dust and
windows in the leaves around the tassel.  Scouting is quick because you
are only looking for the presence or absence of feeding damage.  If you
see damage on a plant, keep a running count of that number.  When you've
inspected 25 plants, multiply the number of plants with holes times four
and this gives you a percentage of field infestation.  If you are over
15% than a control is called for.  

Scout your fields for tassel emergence.  With the warmer weather, the
tassels are opening quickly and since the ECB larvae do not like the
heat, they do not stick around very long.  After tassel, the larvae
either drop down to the ear or they bore into the stem making them more
difficult to eliminate.  When you see around 30-40% of the field with
the tassel just starting to stick out, make your first application.
Since the field will be coming quickly, the time before your second
application will be shorter, maybe 2-3 days.  Keep an eye on your fields
that are about to come into tassel as sprays at tassel are the most
effective at controlling the worms.  For organic growers, Entrust, the
organic formulation of Spintor, works very well. 

 

Potatoes
As stated earlier, late blight has been found on Long Island.  It seems
to rain about every other day.  When you have 18 plus hours of over 90%
RH than conditions are perfect for late blight.  Now that we have late
blight close to our region, it is very important to have protective
fungicide sprays already on the plants. Late blight produces large black
spots on the leaves.  Sometimes, on the stems, you will see black areas
at a stem where a spore germinated.  If you find something you think is
late blight, call  your local Cooperative Extension office and have
someone come out to positively ID the disease or call me at
518-434-0016.

Leaf hopper is being found in very high numbers in most fields.  Go out
and flop a plant into the row and shake it, than flop the plant to the
other side of the row. Inspect the ground for leaf hoppers that have
fallen off the plant onto the ground.  This is an easy way to see what
is happening in the field.  We've already started to see some burning on
susceptible varieties.  The edges of the leaves will turn dark brown.
Eventually the whole plant will turn brown and die.  It's important to
pay attention to leaf hopper because they can seriously decrease yield
without being very evident. For conventional growers, Phaser and Thionex
are the insecticides least toxic to ladybird beetles  This is important
for aphid suppression.  For organic growers, the options are limited.
Pyganic is the only product that is organic certified that will do the
job. 

The only other thing being found in potato fields is bacterial black
leg.  This is when water gets into a damaged stem and causes the stem to
turn black and rot usually producing a strong smell.  You often see this
problem worst in spray rows where the plants are damaged by tractor
wheels.  Later in the season, if the heavy rains continue, you will see
black leg as a result of European corn borer damage. 

Vine crops
We found the first powdery mildew (PM) on summer squash this week.  It
will always be the first vine crop to develop this disease so it is a
good idea to try to isolate it from your other vine crops especially
cucumbers.  Otherwise the PM will jump from one crop and planting to
another. Be on the lookout for Phytophthora crown rot because of all the
rain.  Plants will wilt and the stems will decay at the soil line.
Phytophthora is a common problem in many grower's fields.  We usually
see it later in the season when the fruit collapses.  This early, with
all the rain, we can see the problem on young plants.  Not much to do
but hope we get drier conditions. 

Cornell Recommends
The online version of the 2006 Integrated Crop and Pest Management
Guidelines for Vegetables is now available at 
http://www.nysaes.cornell.edu/recommends/

 

9.  Take a look at this issue of New Ag Network-a newsletter for and by
Upper Midwest organic farmers and educators

http://www.new-ag.msu.edu/ <http://www.new-ag.msu.edu/> 

In this issue -July 12, 2006

 What's causing my vegetables to wilt? <http://www.new-ag.msu.edu/#1#1> 

 

Organic matter amendments and the development of disease suppressive
soils <http://www.new-ag.msu.edu/#2#2> 

 

Economics of organic field crops <http://www.new-ag.msu.edu/#3#3> 

 

United States and regional supply of certified organic field crops and
livestock <http://www.new-ag.msu.edu/#4#4>  

 

Asian soybean rust update for organic producers
<http://www.new-ag.msu.edu/#5#5> 

 

Field day planned in Michigan: Enhancing pollination and biological
control with native plants <http://www.new-ag.msu.edu/#6#6>  

 

10.  Soil Building and Organic Market Workshop

 

On August 23, 2006 Michigan State University and Morgan Compost Inc.
will sponsor a workshop on soil building of organic and biological
systems. We will also offer a time to visit buyers of organic produce
and grains and discuss organic market opportunities.  The day will
feature a speaker from MidWest Biosystems, Roger Kropf, presenting
Building Soil Fertility with integration of compost, cover crop and soil
amendments."  The day will end with a tour of compost production and
incorporation of soil amendments including cover crops and compost.

  For information on the agenda, registration and directions please
visit the web site www.mottgroup.msu.edu <http://www.mottgroup.msu.edu/>
or call Vicki

 

Vicki Morrone

Organic Vegetable and Crop Outreach Specialist

Michigan State University

C.S. Mott Sustainable Food Systems

303 Natural Resources Bldg.

East Lansing, MI 48824

517-353-3542

517-282-3557 (cell)

517-353-3834 (fax)

 

 


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