April 18, 2006 Volume 5 Number 1
1. View from the Field
2. Alfalfa Winter Kill, Root Diseases and Frost Heaving
3. Status of Winter Wheat: Diseases to Watch For!
4. Soybean Rust Center
5. Clipboard Checklist
6. Contact Information
View From The Field
Ken Wise-NYS IPM
Coming to you again is the 2006 season opener of the “NYS
IPM Field Crop Pest Report.” Like last year this will be a statewide
email and on-line publication. The purpose of this publication
is to provide Field Crop Extension Educators with weekly updates
on field crop pests. As in past years, we encourage our readers
to use the material provided in the weekly report in their extension
programming and newsletters. We greatly appreciate any contributions
of pest information and feedback so that we can continue to
make the pest report a useful resource for our audience!
While scouting alfalfa this last week at the Cornell University
Research Farm in Valatie I observed some over-wintering injury.
Most likely this was a combination of root disease and frost
heaving. For more information see article below. No signs of
alfalfa weevil in the fields as of last Friday. With the warmer
weather we have been experiencing we most likely will begin
to see this insect pest soon.
I found a tiny blue weevil last Friday called Ischnopterapion
virens, aka clover stem weevil a pest of clover. This weevil
is native to Europe and is relatively new to the United States.
Adults are metallic blue, about 3/16 inches long, with a distinctive
snout and straight antennae. Adults make small circular holes
in leaves of white clover. Larvae tunnel in the runners of clover
and stems of red clover. The economic damage status of this
weevil is not known.
Alfalfa Winter Kill, Root Diseases
and Frost Heaving
Ken Wise-NYS IPM
There are many potential causes of alfalfa winter kill often
involving some type of root disease. Crown rot, one of the possible
problems can occur in older fields with a history of stress,
heavy traffic or grazing, poor drainage, fertility and pH problems,
previous insect damage, etc. Plants exhibiting crown rot appear
stunted and have few stems. Crown rot progresses slowly in the
crown and taproot area of the plant. In many situations, crown
rot cannot be attributed to a single pathogen. Several fungi
(Fusarium spp., Phoma, Pythium, Rhizoctonia) as well as some
bacteria, have been implicated in the disease. Often, a complex
consisting of several of the pathogens attacks the plant. The
way to tell if a plant has the disease is to dig up (not pull
up) a plant showing symptoms, getting as much of the tap root
as possible. Then use a knife to split open the crown and root.
Healthy tissue should be white, moist, and firm. Rotted tissue
usually has a black or brownish- red color, but the color may
vary from yellowish to pinkish or gray (see photo below).
Another common alfalfa problem observed this time of year
is frost heaved crowns. Low areas of the field that tend to
accumulate water are sites worth checking for this ailment.
Frost heaving may indicate potential disease problems such as
Pythium or Phytopthora root rot which attack lateral and main
root systems leaving plants with limited holding power for staying
in the ground. The photo shown came from a field in Freeville
NY (Year 2004) which was poorly drained and had a history of
Phytopthora root rot.
Status of Winter Wheat - Diseases
to Watch For
Julie Stavisky-NYS IPM
Many wheat fields I’ve observed this spring are greening
up fast and growing well. But there are some problem areas,
too. Bare spots in fields may be the result of unhealthy plants
that do not grow vigorously in the spring due to infection with
pathogens that cause root and crown rots.
Many different fungal organisms cause root and crown rot
diseases of wheat, and it is often difficult to distinguish
which causal agent is present. The most common organisms that
cause root and crown rots include Fusarium and Pythium. Seedling
blights and rots are more likely to be severe under excessively
wet conditions and when soil temperatures are too low for good
growth. Plants injured from frost heaving, resulting from repeated
freezing and thawing, are especially vulnerable. Over the past
winter, we didn’t have snow cover to insulate plants, so dormant
plants were more exposed to the elements than usual.
Fusarium seedling blight: Seedlings and tillering plants
infected with Fusarium seedling blight are generally stunted
and yellow, and the crown, roots, or lower stem take on a brown
to reddish-brown water-soaked rotten appearance. If plants survive,
they have a brittle, stunted appearance and are paler green
than healthy plants. Plant death can result in patchy stand
reduction. The Fusarium fungi can survive in plant residue or
as dormant spores in the soil for several moths.
Pythium root rot: The “water mold” that causes Pythium root
rot may first infect the seedlings in fall-planted cereals,
though seedlings are rarely killed. The stunting of seedlings
resulting from Pythium infection may go unnoticed until other
plants in the field begin healthy, vigorous growth in the spring.
Roots of infected plants begin to turn brown then disintegrate
beginning at the root tips. Plant mortality can occur if infection
is severe enough for the rotted roots to break away from the
crown. Pythium spores survive several years in soil without
a host, and spores are present in all soil types. Infection
of plants is greatest in cold, wet, clay soils.
Soybean Rust Updates
Julie Stavisky-NYS IPM
The USDA soybean rust website (http://www.sbrusa.net/)
New York State Soybean Rust Information Center will continue
to be our best first resource as things develop in the soybean
crop this year.
Keith Waldron-NYS IPM
* Walk fields to check tile flow, check and clear drainage outlets.
Look for line breaks.
* Observe wet areas and plot on aerial photo of farm for future
drainage considerations and crop decisions
* Maintain crop records by field, including variety, planting
date, pesticides used, nutrient inputs including manure, etc.
* Watch for early season weeds: winter annuals, chickweed, henbit,
field penny cress, shepherd's purse, giant ragweed, lambsquarters,
Pennsylvania smartweed, common sunflower
Alfalfa and Small Grains:
* Monitor alfalfa for Alfalfa Snout Beetle (In Oswego, Jefferson,
Cayuga,Wayne, Lewis, St. Lawrence, Clinton, Essex, and Franklin
* Monitor alfalfa for Alfalfa weevil as weather continues to
* Evaluate established legume stands for winter damage, determine
average alfalfa stand count, adjust crop plans if necessary
* Monitor winter grain fields for virus disease symptoms
* Prepare land for corn if it is dry enough and begin planting
the last week of April if it is dry (even if it is cold!)
* Check and mend fences as needed.
* Check crop growth
* Review/Plan rotation system
* Check forage allocation and anticipate feed program adjustments
as forages from previous year are used up
* Plan where forages should be stored for optimum allocation
next feeding season
* Arrange for custom weed control or check your own application
or cultivator equipment for repairs.
* Check nozzles, pumps, etc., recalibrate pesticide application
equipment regularly before use.
* Calibrate manure spreaders - maintain records on amount spread
Julie Stavisky: IPM Area Educator, Livestock and Field Crops,
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
Phone: (518) 434-1690
Fax: (518) 426-3316