August 26, 2005 Volume 4 Number 19
1. View from the Field
2. Stop! Check for Corn Ear Rot
3. Think Weeds in the Fall!
4. Keeping Pest Records
5. Soybean Rust Update
6. Growing Degree Days in NYS
7. Clipboard Checklist
8. Contact Information
from the Field
the soybean TAg team in Orleans County, Nancy Glazier (NWNY
Team) reports that pests are really winding down. Most beans
are in the R-6 stage, indicating that maturity is approaching
fast and actions for pest management are unlikely to provide
an economic benefit. In the very northern areas of Orleans County,
fields are still extremely dry and plagued by spider mites.
Following up on diseases previously reported on by Nancy, downy
mildew is still prevalent, and the Phytophthora outbreak reported
on several weeks ago has not progressed to any serious extent.
Soybean aphids are generally few and far between, with some
of the small white forms of the aphids being observed (“white
dwarves”). It is suspected that soybean aphids take on this
appearance as nutritional value of the leaves declines during
Wyoming County, potato leafhopper numbers were low in Julie
Hansen’s (Cornell Plant Breeding Department) alfalfa variety
trial. In Cattaraugus County, Dean Sprague (CCE of Cattaraugus,
Allegany, and Chautauqua Counties) and I noticed that grasshoppers
were extremely abundant in a grass/clover hay field, but feeding
damage was not severe.
week while in Orange County we were in a field that had many
problems. First was that the corn was drought stressed and had
not received rain in weeks. The second issue was there was much
damage to the corn by birds and deer (See picture).
allows pathogens to enter the ear of corn and reduce yield and
quality of the crop. Here is a picture of what can happen when
the ears are opened by a vertebrate pest.
is a picture of common smut attacking an ear of corn and part
of the stalk. For more information on corn ear diseases please
refer to the next article.
spotted spider (TSM) mite injury evident on many drought stressed
soybean fields. First indication of a problem is often the appearance
of chlorotic, stunted plants on the field margin. Close inspection
of individual plants shows leaves with a stippling of fine yellow
dots on the upper surface and presence of small mites with two
spots on the underside of leaves. Mites tend to congregate in
the leaf vein areas. A webbing under the leaves can accompany
higher TSM populations. Field symptoms extend interior from
margins into the field in a "V" shaped pattern, the
smallest point of the "V" going into the field. From
this infestation spider mites use their ability to create a
fine web strand as a means to "balloon" into the field
riding the prevailing winds. This new infestation develops over
time into a circular area of chlorotic, stunted plants. A patchy,
spotty chlorotic appearance to fields may warrant inspection
for spider mite damage.
Check for Corn Ear Rot
Wise, NYS IPM
you ready with the chopper or combine? STOP; check for corn
ear rots first! Some kinds of fungi can create mycotoxins that
are toxic to livestock. Taking a few minutes to check a field
for certain ear rots can help you determine if you want to feed
your field of corn to livestock. Pull back the husks on several
plants and look for the presence mold growing on the ear of
corn. The following are specific symptoms of certain ear rot
diseases that can be found in NYS:
Ear Rot appears as a white-to-pink or salmon-colored mold.
This mold can begin with bird, deer or insect-damaged kernels.
Fusarium ear rot may contain fumonisins which are mycotoxins
that can be toxic to livestock.
Ear Rot symptoms are pink to reddish colored mold. This
disease starts near the tip of the ear and progresses down toward
base of the ear. Gibberella can produce vomitoxin and zearalenone
which is toxic to many kinds of livestock.
Ear Rot symptoms appear as a thick white mold that usually
starts near the base of the ear. This disease can also appear
on the plant as raised black fruiting bodies on moldy husks
or kernels. Diplodia does not produce any known toxins.
Ear and Kernel Rot symptoms appear as greenish black, blotched
or streaked kernels scattered over the ear. This disease can
also infect kernels that have been damaged by insects, birds,
deer, hail, or frost. The disease can progress after the grain
is harvested and stored.
ear rot or blue eye symptoms range from a powder-like green
or blue-green mold that is on and between the kernels and normally
on the tip of the ear. If this disease progresses in storage
it is referred to as blue eye because the germ is a bluish-green
color. Penicillium ear rot can produce a mycotoxin called “ochratoxin”.
you discover certain ear rot diseases make notes of the hybrid,
tillage methods, rotation history, and planting date. By doing
this you can avoid the disease occurrence in the future. The
following is the effectiveness of specific management practices
for corn ear rots:
Crop Clean Plow
Disease Variety Rotation Down of Residues Fungicides
Rots 2 2 2 4
highly effective, 2= moderately effective, 3=slightly effective,
4= not effective, 5 = not usually economical,
Purdue University Field Crops Pest Management Manual
there isn't any practical solution for coping with ear rots
this late in the current season proper fertilization, timely
weed control and reductions in insect pest pressure can help
reduce risk of disease. For example: European corn borer (ECB)
resistant Bt corn is at lower risk for injury by this insect.
Lower risk means fewer ECB tunnels into stalks and less potential
for fungi to infect through wounds and cause stalk rot. Also
avoid continuous planting of corn under conservation tillage
where stalk rot can be prevalent. If you are harvesting corn
grain make sure you clean the grain bins. Keeping the proper
temperature, moisture content and good aeration in the grain
bin can reduce storage molds from developing. It is important
to have regular inspections of the stored grain. This is essential
to minimize risk of developing insect and mold associated storage
problems. Harvest silage at recommended maturity and moisture
level, and pack silage tightly and exclude air rapidly. Consider
using organic acid preservatives if you can't exclude air or
reduce moisture. If you had a lot of stalk rot and were growing
for grain consider chopping earlier for silage to minimize lodging
and combine losses. There are kits you can purchase to test
your corn for different toxins on your own farm. The following
are places where you can also test your corn:
One Forage Lab in Ithaca: For more information, call the lab
at 1-800-496-3344 extension 172.
The Cornell College of Veterinary Medicine's Nutritional and
Environmental Analytical Services Lab: More information is available
on the web (www.vet.cornell.edu/public/neas/) or from
lab manager Joe Hillebrandt at 607-257-2345
Weeds in the Fall!
Wise, NYS IPM
the fall, weeds are fully-grown and easily identified. Correctly
identifying and recording significant weed infestations and
their location is helpful for improving weed management decisions.
Knowing the weed type and biology (broadleaf, grass, sedge,
summer or winter annual, biennial, or perennial) is critical
in selecting the right weed control measures. Remember, while
herbicides are widely used for weed control other methods like
crop rotation, cultivation, proper fertilization, planting dates,
banding pre-emergence herbicides, crop spacing, plant populations,
cover crops and combinations of these techniques should also
be considered as part of an integrated weed control program.
Conduct your fall weed surveys from late August through October.
Sketch out a map of the field, walk each 1/4 of the field, and
record the identity and relative infestation of the significant
populations of weeds you observe. While no economic thresholds
have been developed for weeds in New York, we recommend using
a weed rating scale. The following scale can help you determine
the severity of weed infestations in cornfields.
Weed Presence- Weed Rating Scale:
Determine the intensity of each weed species as follows:
No weeds present
Weeds present but very few plants within the field. Enough plants
to produce seed but not enough to cause significant economic
loss in the current year.
Plants dispersed throughout the field, an average of no more
than 1 plant per 3 feet (.91m)
of row, or scattered spots of moderate infestation.
Fairly uniform concentrations across field. Average concentrations
of no more than 1 plant per foot (.30m) of row or scattered
spots of severe infestations.
More than 1 plant per foot (.30m) of row for broadleaf weeds
and 3 plants per foot of row for grasses, or large areas of
take a few minutes and encourage growers to look at their fields---it
will help save on weed control costs and increase crop production.
Remember, if you don't look, you will never know. For more information
on weeds in corn checkout our online publication: Weeds
in Field Corn
Wise, NYS IPM
is very important to keep records from year to year on certain
pest problems that may have occurred. Write down observations
that you made over the season. Did potato leafhoppers go over
threshold and which field(s)? Were there certain corn diseases
present? Did you have corn that had corn rootworm injury? Were
there new weeds or weed escapes you did not expect this year?
Pick up a pencil and write them down on a field to field basis
to better select certain management practices the next season.
For example, if you were hit with potato leafhoppers this season
and you want to rotate your alfalfa, one management option to
consider for the future is use of a potato leafhopper resistant
alfalfa variety. Another example might be to select wheat varieties
that are resistant to certain diseases. If you had weed escapes
you might reconsider your selection of weed control products.
Are your pesticide use records up to date? Rates, dates, efficacy,
etc. It is always important to keep pesticide records up to
date. If you wait too long you may forget what happened in certain
fields. So write them down! A sharp pencil beats a dull memory…
Waldron, NYS IPM
Asian Soybean Rust Status
rust was most recently confirmed in southern South Carolina
and central Georgia. This is the first report from South Carolina
in 2005. These are currently the most northern reports of soybean
rust in the U.S. To date, positive confirmation of soybean rust
has been reported in Alabama, Florida, Georgia, Mississippi
and South Carolina. Scouting and spore trapping continues throughout
the soybean production areas of the U.S. Scouting of sentinel
plots in New York State continues this week and to date no soybean
rust has been found. The risk of soybean rust infection in New
York is currently considered to be low and no fungicide application
for soybean rust is advocated at this time. Growth stages in
New York State sentinel plots range from R5 to R6. (Last updated
Degree Days in NYS
1 - August 25, 2005
Waldron, NYS IPM
Maintain crop production activity records by field, including
harvest date, pesticides used, nutrient inputs including manure,
Check fall harvest equipment, sharpen chopper knives, check
shear clearances, check protective shields on all harvest machinery
Check bunkers and silos. Prepare for corn silage.
Mow weeds around barn, grain storage bins, farm buildings, pastures,
control weeds, brambles.
Continue monitoring for potato leafhopper -harvest early or
spray on basis of need.
- HALVE PLH thresholds for fields under drought
Monitor fields for weeds and diseases: record information on
type and location for future cropping decisions.
Harvest third cutting of alfalfa about 40 days after second
Record hay yields by field and quality by storage facility;
take samples for forage analysis
Monitor corn rootworm adults at silking.
Observe corn for weeds, stalk rots / lodging, and nutrient and
Monitor for soybean aphid (SBA), soybean rust, pod, stem and
foliar diseases. When checking for SBA, look for winged forms
as an indication that the population may soon leave the field.
Continue manure management and release of biological control
agents (parasitic wasps) for house fly and stable fly control.
Monitor young stock for cattle lice and mange mites
Check condition of pastures and animals on pastures:
Evaluate need for face fly, horn fly, and stable fly control
Stavisky: IPM Area Educator, Livestock and Field Crops, Western
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