August 12, 2005 Volume 4 Number 17
1. View from the Field
2. What Pest Problems to Consider When Planting
3. How Important is European Corn Borer in Field
4. Check for Stalk Rots
5. Growing Degree Days in NYS
6. Clipboard Checklist
7. Contact Information
On top of seeing a lot of drought
stressed corn and soybeans I have seen an excess of corn ear
damage created by deer, birds and even chipmunks. The husk covering
the corn was pulled back and about a third of the grain was
gone. Some of the ends of the ears were bitten right off by
deer. In addition, the open husk can allow a variety of diseases
to infect the ear of corn. Some of these diseases might be:
Fusarium ear rot,
Gibberella ear rot,
Diplodia ear rot,
Cladosporium ear and kernel rot, and more.
Substantial rainfall in parts of Cayuga, Seneca, Wayne, and
Ontario Counties this week provided much-needed relief for soybeans
and corn. Rain will also help in the battle against spider mites.
Natural enemies of spider mites (including predators and fungal
pathogens) can do a great job of alleviating a spider mite infestation
in soybeans, but the natural enemies are moisture-dependent.
Spider mites continue to pose a threat to soybeans in Orleans
County, and Mike Stanyard (NWNY Team) reports on a serious spider
mite infestation in Monroe County.
Reports of white mold in soybeans have come in from Cortland
What pest problems to consider when planting
There are several factors to consider
when planting winter wheat. The first is to never plant wheat
in the same field two years in a row. By rotating you reduce
the risk of several diseases like eyespot foot rot, powdery
mildew, leaf rust, stagonospora nodorum blotch, glume blotch
and more. The second item to consider is what winter wheat variety
to plant. Of course you will look at potential grain yield,
grain test weight and straw quality. It is also important to
consider resistance to diseases in the varieties you select.
Diseases of particular concern are wheat spindle streak mosaic
virus, soil borne mosaic virus, yellow dwarf virus (formally
called “barley yellow dwarf virus”), powdery mildew, leaf &
stem rust and/or other disease problems your farm has had in
previous years. For a list of potential wheat varieties consult
your Cornell Guide for Integrated Field Crop Management
(available online at www.fieldcrops.org).
Next, remember to plant AFTER the Hessian fly free date.
By doing so, not only are you avoiding infestations of Hessian
fly but also certain aphids that can transmit yellow dwarf virus.
The following figure shows the “Hessian Fly Free Dates” in NYS:
The use of certified wheat seed should be considered. When
seed is certified you can be confident of the quality and it
is void of diseases and weed seed. Next is to remember to always
use a fungicide seed treatment to protect the crop from certain
seed and seedling related diseases. Another core consideration
is having a sound fertility program. When a plant is healthy
it can complete with weeds and may tolerate more insect pest
pressure and still maintain good yield.
is European Corn Borer in Field Corn?
Catches of European corn borers
(ECB) in pheromone traps have increased dramatically over the
past 2 weeks. The trapping data is available from
The Sweet Corn Pheromone Trap Network coordinated by Abby
Seaman with the NYS IPM Vegetable program. The increase in numbers
of ECB indicates that the second generation of moths is flying.
While ECB causes much less worry in field corn than in sweet
corn, concern about severe ECB infestations and the disease
problems that may follow requires our attention.
The primary injury from the second generation of ECB is caused
by the larvae tunneling into stalks and ear shanks (see
photo), which can result in poor ear development, broken
photo), and dropped ears. The later in the kernel-filling
period that an ECB infestation starts, the lower the yield impact
will generally be.
To scout for ECB in August, look for egg masses on the undersides
of leaves near ear level on the plant. Tunneling larvae can
be found by looking for areas of frass (insect droppings) at
the point of entry into the stalk.
At times, a large infestation of ECB may cause a localized
problem. Late harvesting and/or adverse weather conditions that
cause plants to break at the points of injury may exacerbate
those losses. Although the ECB damage can be conspicuous on
an occasional plant, it does not generally cause significant
yield losses in NY in corn harvested for grain or silage. However,
drought stress conditions (which corn is experiencing in many
locations in NY this year) can magnify the effects of ECB damage.
Another reason to be concerned with an ECB infestation is that
stalks or ears injured by ECB can be the entry point for disease-causing
organisms. For more information, see Ken’s stalk rot article!
Ken Wise, NYS IPM
It is important to monitor your
fields for stalk rots as you start thinking of your corn harvest.
If you have an infection of stalk rot it can cause the plant
to die early losing grain or silage yields. Stalk rots are caused
by many different fungi that enter the plant. They occur when
the plant is under stress or when it may be injured by insect
pests, hail, deer and bird damages, drought or soil saturation,
lack of sunlight, extended cool weather, and the lack of fertility.
The following are symptoms of specific stalk rots:
Anthracnose stalk rot symptoms may appear after tasselling
as vertical, tan to reddish brown, water-soaked lesions (streaks)
in the stalk rind. Lesions become large, dark brown to shiny
black. Fields with high amounts of anthracnose leaf blight (both
diseases have the same causal agent) should be checked for indications
of anthracnose stalk rot.
Diplodia stalk rot symptoms may appear as numerous black
pycnidia in the lower internodes of the stalk. The black dots
are the size of a pinhead or smaller. When conditions are wet
a white mold may develop on the stalk surface.
Fusarium stalk rot normally starts just after pollination
and symptoms appear later in the season. When you cut open the
stalk, the pith appears as a whitish to pink (salmon) color.
There are also distinctive brown streaks on the lower internodes.
The first symptom of
gibberella stalk rot is the onset of grayish-green color
of the leaves. The stalk will turn dark green to tan near the
base of the plant. The pith of the stalk becomes soft and will
appear as a red to pinkish color.
Pythium stalk rot normally appears as a decay of the first
internode above the soil. The pith will become soft, turn brown
and appear water-soaked. Many times the stalk can twist and/
or lodge. Even though it may have lodged the plant will stay
green for several weeks because the vascular tissue is not destroyed.
If you discover certain stalk rot diseases make notes of
the hybrid, tillage methods, rotation history, and planting
date. By doing this you be able to avoid the disease occurrence
in the future. The following is the effectiveness of specific
management practices for stalk rots:
Resistant Crop Clean Plow
Corn Disease Variety RotationDown of Residues Fungicides
Anthracnose 1 1 1 4
All other 2 3 3 4
1= highly effective, 2= moderately effective, 3=slightly
effective, 4= not effective, 5 = not usually economical,
Reference: Purdue University Field Crops Pest Management
As with most diseases that attack corn, if you can reduce
stress on the plants you most likely can reduce the occurrence
of certain stalk rots. Having a sound fertility program based
on soil testing is important for keeping a corn plant healthy.
Select a hybrid with resistance to certain diseases and good
standability that is adapted to your region. Some of these stalk
rots can produce mycotoxins that can be toxic to livestock.
You should consider having silage tested for certain mycotoxins
if you had fields with stalk rots this season. For more information
on corn diseases checkout our online publication:
IPM for Corn Diseases
Growing Degree Days in NYS
March 1 - August 11,
Base 50 F
• Maintain crop
production activity records by field, including harvest date,
pesticides used, nutrient inputs including manure, etc.
Alfalfa & Hay:
• Continue monitoring for potato leafhopper- harvest early
or spray on basis of need.
• Monitor for diseases> >and >record
information on type and location for future cropping decisions.
• Monitor for foliar and stalk diseases, nitrogen and other
nutrient deficiencies, European corn borer, weeds.
• Monitor corn rootworm adults at silking.
• Monitor for soybean aphid, soybean rust, foliar diseases,
• Continue livestock facility sanitation
management (manure, feed bunks and storage areas, waterers,
etc.). Cleaner barn, less fly production
• Mow around facilities to minimize rodent habitat.
• Monitor young stock for cattle lice and mange mites
• Check condition of pastures and animals on pastures
- Evaluate need for face fly and stable fly control measures
- Check and clean pasture water supplies.
Julie Stavisky: IPM Area Educator,
Livestock and Field Crops, Western NY
Phone: (315) 331-8415
Fax: (315) 331-8411
Keith Waldron: NYS Livestock and Field Crops IPM Coordinator
Phone: (315) 787 - 2432
Fax: (315) 787-2360
Ken Wise: Eastern NYS IPM Area Educator: Field Crops and Livestock
Phone: (518) 434-1690
Fax: (518) 426-3316