June 2, 2006 Volume 5 Number 7
1. View from the Field
2. Barn Fly Natural Enemies
3. Alfalfa Weevil Biological Control Continued
4. Soybean Seed Rots and Seedling Blight
5. Soybean Rust Update and USDA Soybean Rust Website
Now Includes Soybean Aphid Reports
6. Growing Degree Days in NYS
7. Clipboard Checklist
8. Contact Information
View From The Field
Julie Stavisky, NYS IPM
Ken Wise, NYS IPM
Keith Waldron, NYS IPM
At a TAg team meeting in Onondaga County in the Skaneateles Lake
Watershed this week, corn that was planted in early May was finally
starting to green up and grow.
When we conducted stand counts in corn field during a TAg meeting
in Cattaraugus County this week, many skips were observed in the
rows. In most places where we did a little digging, we found
seeds still trying to poke through the soil surface. One persistent
TAg team member unearthed a white grub larva feeding on the roots
of a seedling, and some instances of kernel damage were seen nearby.
This is a first year corn field following an alfalfa/grass stand
(mostly grass by the last year), and it isn’t a surprising circumstance
in which to see an occasional white grub.
On May 27th in Monroe County, I saw my first potato leafhopper
of the year. I would not be surprised if they are widespread
in NY by now. Once some new growth starts to show following
the first cutting, it’s time to start scouting for PLH in alfalfa!
This week I scouted the SUNY Cobleskill farm and found my first
potato leafhopper…just one! I did find a lot of aphids and ladybeetles.
Next week I will have an article on ladybeetles in alfalfa. Here
is a photo of an aphid mummy! An aphid mummy is really an aphid
that had been parasitized by a parasitoid. The parasitoid lays its
eggs inside the aphid and once it develops into a larva, it feeds
on the inside of the aphid, thus, killing it.
Most of the alfalfa was severally lodged from the thunderstorm
we have been receiving the last few days. In fields that are 2 plus
years old alfalfa weevil tip feeding was 30 to 40 percent. Remember
threshold for first cutting of alfalfa is 40 percent tip feeding.
In a new seeding there were many weeds competing with the new
alfalfa plants. There are yellow nutsedge, lambsquarter, crabgrass
and velvetleaf weed seedlings in abundance.
I found one lonely PLH found while sweeping and established alfalfa
field at NYSAES farm. The alfalfa at 26 inches and should be harvested
soon. I observed many alfalfa weevil larvae and extensive feeding
injury this week. These established fields are very close to the
economic threshold for AW.
Again I found no soybean aphids on buckthorn. I'm thinking it
would be better to check buckthorn in an area that had soybeans
recently. NYSAES farm has not had any appreciable acreage of soybeans
planted in years.
Gary Bergstrom confirms a sample I left with him recently found
on buckthorn as aecia of the crown rust Puccinia coronata.
It could be the variant from oat, rye, or some other grass.
Barn Fly Natural Enemies
Keith Waldron, NYS IPM
Look closely in areas of spilled silage, soiled calf bedding
and moist organic matter in the barn and chances are you’ll be able
to find one of several species of natural enemies of house and stable
flies. Beetles and mites devour fly eggs and larvae. Fly pupae are
attacked by small parasitoids (wasp spp). Fungi can cause disease
to adult flies. Generally unnoticed and unaided by us, these natural
biocontrol agents can take a heavy toll on the fly population.
Sanitation and other cultural practices minimize fly breeding
habitats and interfere with the successful completion of the fly
life cycle. In addition to reducing fly populations and minimizing
the need for insecticide use, these practices protect natural enemy
survival and help insure that they will be available to assist in
This time of year we get a number of requests for information
on enhancing biological control of barn flies. Parasitoids have
been well studied by Veterinary Entomologists in NY for their effectiveness
at reducing house and stable fly populations in and around animal
facilities. Research has shown that some species perform better
in different climates, and some prefer different kinds of manure
and other fly breeding materials. The species that is best adapted,
occurring naturally on many dairy farms in the Northeast, is Muscidifurax
raptor. This species attacks fly pupae inside barns as well as outside.
Much of the following information is adapted from the Cornell
Integrated Management of Flies in and around Dairy and Livestock
Parasitoids are like "smart bombs"-they live only to find and
kill fly pupae. Although the female parasitoid has a stinger, the
only purpose she can use it for is to kill flies. When she finds
a fly pupa, she stings and feeds on it. This kills the fly. She
then uses her stinger to lay an egg inside the pupa. The egg hatches,
and the parasitoid larva feeds on the dead fly. The young adult
parasitoid then chews its way out of the fly's pupal case and searches
for new pupae to kill. Development from egg to adult parasitoid
is completed in about 3 weeks. This extended development time compared
to a house fly life cycle from egg to adult fly in as little as
5 days under ideal conditions is the reason why one would consider
purchase and release of these parasitoids. If we think of them as
competitors in a race that happens each summer, the fly has certain
advantages that help it to win unless we intercede. For example,
the fly develops twice as fast from egg to adult, lives longer,
and lays more eggs than Muscidifurax raptor parasitoids. As fly
populations begin to grow in late May and early June, the parasitoid
populations lag behind.
The parasitoid also lags behind the fly in developing resistance
to insecticides. Many insecticide treatments for flies therefore
have the undesirable side effect of killing large numbers of parasitoids.
Each subsequent insecticide treatment kills more beneficial insects
and creates conditions that require repetitive treatments to keep
flies in check.
Parasitoid populations can be conserved by using insecticides
that are compatible with these important biocontrol agents. Baits
and pyrethrin space sprays are good examples of compatible insecticides.
Residual premise sprays are highly toxic to parasitoids and should
be used only as a last resort.
Along with conserving natural enemies, it is possible to go one
step further and release parasitoids to "jump-start" their population
growth in the early summer. Such releases can be effective in managing
fly populations if certain conditions are met:
Sanitation (waste management) is a must; parasitoid releases
complement manure management but cannot replace it – i.e. there
are No Silver Bullets….
When insecticidal treatment is necessary for supplemental
fly control, only use insecticides that are compatible with
parasitoids (space sprays and baits).
Parasitoids are sold in containers as immature insects in
killed fly pupae. If most fly breeding on the farm occurs inside
the barn, two or three tablespoons of the parasitoids should
be distributed in areas where fly breeding is a problem. If
calves are housed in hutches, about three heaping teaspoons
of pupae (approximately 1,000) placed in each hutch weekly.
Many companies that sell parasitoids advertise their products
in farm magazines, but not all of them sell the right species
or provide parasitoids that are adapted for the northeastern
climate. Muscidifurax raptor is the species recommended for
use in the Northeast. Nasonia parasitoids are inexpensive but
are inappropriate for use in dairies.
Parasitoid releases should be started early, preferably in
middle to late May, and continue weekly until the middle of
How many parasitoids should be released? Weekly releases
of either 200 parasitoids per milking cow or 1,000 parasitoids
per calf have proven effective in research trials. But every
farm is different, and release rates and schedules may require
adjustment to achieve a level that is both effective and affordable
for an individual farm.
In research trials, the cost of releasing parasitoids has
been more than offset by reductions in insecticide treatments.
On average, dairy farmers who use biocontrol in fly IPM programs
make 80 percent fewer insecticide treatments than farmers who
rely solely on insecticides for fly control. In addition, fly
populations on IPM farms are about 50 percent lower than on
conventionally managed farms. It is important to understand,
however, that no single fly management strategy such as parasitoid
releases alone will provide long-term control.
Check locally for producers of distributors of parasitoids.
IPM Laboratories, Inc. (Locke, NY. 315-497-2063, Email -
email@example.com ) is one source of M.raptor parasitoids.
For more information:
Pdfs of the dairy cattle recommendations, factsheets and more
can be found at
Veterinary Entomology at Cornell and
NYS IPM for Livestock.
Alfalfa weevil Biological Control, Continued
Julie Stavisky, NYS IPM
Large numbers of 1st through 3rd instars have been seen in localized
areas. For example, take a look at this photo of a handful
of alfalfa weevil larvae collected by Mike Stanyard in Yates county!
The field where these were collected was showing heavy, over-threshold
injury in one area. Insecticide treatment will not be necessary
because the field will be cut within a few days.
In addition to the parasitoids we talked about in last week’s
pest report, another biological control friend in alfalfa is an
entomophagous fungus. Yes, it’s an insect-feeding fungus.
Its only choice for breakfast, lunch, and dinner is the alfalfa
Light (but widespread) rains at the end of last week may provide
a big advantage for keeping alfalfa weevil larval numbers in check.
Given that most alfalfa weevil larvae have not reached the 4th instar
(the most damaging stage), but many fields are being cut, larvae
could pose a threat to early re-growth. So we’ll take all the help
we can get from biological control agents for protecting alfalfa.
The fungal pathogen, Zoophthora phytonomi, is always present
in low levels in and around alfalfa fields. Under the right cool,
wet conditions, an epizootic, or outbreak, of the fungal pathogen
can occur. Infected larvae lose their normal light green color.
The pale yellow infected larvae become less active and usually die
within a few days.
Zoopthora phytonomi first appeared in Ontario, Canada
in 1973, and now commonly occurs throughout the weevil’s range in
the Midwest and northeast. Although there are several theories
about where the fungus might have come from, its origin remains
a photo showing what you may see if you find infected alfalfa
Soybean Seed Rot and Seedling Blight
Ken Wise, NYS IPM
Many different organisms cause seed rot and seedling blights.
Most of these organisms are soil-borne and a few are seed-borne.
Most seed rots and seedling blights proliferate in poorly drained,
cold (less than 58 degrees) and wet soils.
Seed Rot: Many times the infected seed will not germinate. If
the seed does germinate the radicle will become infected and rot.
The rot can be tan, brown, gray or black and the seed or radicle
will appear wet and mushy. Some of the organisms that infect seed
are Pythium, Fusarium, and Rhizoctonia.
Seedling blight: It is difficult to determine which pathogen
causes seedling blight in any one field. Many times it can be a
complex of Pythium, Rhizoctonia and Phytophtora. Pythium can cause
the seedlings to have a wet, rotted appearance, while Phytophtora
generally appears as a dry, dark rot on the roots. Sunken,
reddish-brown lesions on the hypocotyls are most likely a Rhizoctonia
infection. The Rhizoctonia lesions are small when they first appear.
As these lesions grow they can girdle the stem, causing the soybean
plant to die. If the Rhizoctonia infected seedlings do not kick
the bucket the infection will weaken the stem and may cause the
plant to lodge after the pods form.
Soybean Rust Update
Keith Waldron, NYS IPM
USDA Soybean rust website now includes soybean aphid reports
The current risk of soybean rust infection in New York is extremely
low. Future risk in New York will depend on rust build-up in the
southern U.S., especially in commercial soybean fields. The 2006
North American epidemic is starting from over-wintered rust on kudzu
in a somewhat broader and more northerly area than in spring 2006,
yet early pockets of rust from Florida to Alabama are scattered
and of low severity. Rust development is basically in a holding
pattern along the Gulf Coast. Despite recent rains across the South,
the region is again in an overall pattern of hot, dry weather.
To date, in 2006, soybean rust has been reported on kudzu in five
counties in Alabama, 11 counties in Florida, and four counties in
Georgia. While soybean rust was found in a mature field of
soybean in far southern Texas in February, the infected field has
since been destroyed and no new rust has been found in Texas.
Scouting continues on kudzu patches from Florida northward to southern
Illinois, and westward to Texas and Nebraska. Many of the soybean
sentinel plots have been planted throughout the country with the
most advanced ones in the south starting to fill pods. We are finalizing
plans for approximately 20 sentinel soybean plots in New York to
be scouted in cooperation with soybean producers and Cornell Cooperative
Extension Educators. Sentinel plots are planned for locations in
Cayuga, Chautauqua, Chemung, Chenango, Genesee, Jefferson, Montgomery,
Oneida, Onondaga, Ontario, Orleans, Seneca, Steuben, Tompkins, and
Wayne Counties. Last updated (May 26, 2006)
We have been reprinting Gary Bergstrom’s soybean rust updates
and a link to the NY Soybean Rust (SBR) website. The NY website
provides NY producers with our best recommendations regarding risk
of the disease and help producers better time scouting and apply
preventative fungicide applications. The NY SBR site will also provide
updates on observations of sentinel plot activities.
The USDA also has a soybean
rust web site which presents the national perspective for SBR
observations and recommendations. Information on that site documents
SBR detections in soybean sentinel plots and on kudzu, an alternate
rust host. Specialists also present their individual state’s commentary.
This summer the USDA site is adding information on soybean aphid
(SBA) detections across the US. State commentaries for SBR and SBA
observations will follow a standard format highlighting:
Crop Growth Stage, Observation and Outlook – Insect, Observation
and Outlook – Disease, Scouting and Management – Insect, and Scouting
and Management – Disease.
For SBA information enter the website, and go to the drop down
menu in the top right corner,. Under the date, select soybean aphid.
Two maps appear on the right side of the screen. The top map shows
“SB Aphid Observations.” As of this writing (June 1) this map is
blank (it isn’t active yet), but once reports of soybean aphid come
in, dots will appear. Commentary is currently available for the
states colored. Unlike the rust map, which only has two colors
(green for no detection, red for detection), the color of the dots
on the aphid map will reflect the number of SBA per plant with purple
dots indicating fields or plots over the 250 per plant threshold.
The second map has the “SB Aphid State Update,” commentary by state
specialists. Note that the color of the state reflects when the
commentary was last updated. USDA is funding the sampling of sentinel
plots in some states for aphids. NY is voluntarily participating
both SBR and SBA data input contributing to this data set with observations
from sentinel plots and other locations across the state. We welcome
you to share your SBR and SBA observations. Please share these observations
with the fcrops bb and with either Gary Bergstrom (firstname.lastname@example.org)
or Keith Waldron (email@example.com)
A note of caution about the soybean aphid web site – (some comments
and material adapted from a 5.25.06 article by Chris DiFonzo
in the Michigan Field Crop CAT Alert.) Entomologists agree this
map should not be used to make spray decisions in your individual
fields. This is different from how the rust maps are used. Detections
of rust near your location will help to time preventative fungicide
applications across a region. Watch Gary Bergstrom’s SBR website
for recommendations appropriate for NY. However, detecting soybean
aphid in your area and even having fields go over threshold does
not necessarily indicate individual fields should be treated. SBA
populations have been very variable across NY. Field to field variations
even on the same farm may be dramatic. Only a relatively few fields
in NY have exceeded the 250 SBA / plant threshold and required treatment.
We also know from our limited experience that natural enemies can
have a significant impact on aphid populations. It is also known
that optimal timing of insecticide applications, when warranted,
can protect yield. These factors argue for scouting as needed and
making field-by-field decisions. Use the soybean aphid maps to get
information about aphid populations in general, but do not use the
maps to make a decision about whether or not to treat your own fields.
For more information, consult:
Alfalfa Weevil and Growing Degree Days
Ken Wise NYS IPM
Growing degree Days for peak (50%) Occurrence of Alfalfa Weevil
Stage or Event
Accumulated growing degree days (48F base temperature)
(Note: for alfalfa weevil predictions use Base Temp of 48F)
Accumulated Growing Degree Days for March 1 to May 24
Base 48 F
Base 50 F
187* (Many days not recorded)
*indicates missing data
Do you know the number of growing degree-days in your region
today? Check this website:
NY Growing Degree-Day Tracker Base Temp. 50F.
Keith Waldron-NYS IPM
• Maintain crop records by field, including variety, planting
date, pesticides used, nutrient inputs including manure, etc.
• Watch for early season weeds, any patches of herbicide resistant
• Storage areas cleaned and ready to accept upcoming hay harvest?
• Determine plant populations, make notes on germination problems
• Gaps in row? Check for seed corn maggot, wireworm, cutworm,
seedling blights, birds, seed placement issues?
• Monitor for weeds, note presence of “who”, “how many” and “where”
• Adjust post emergence weed control actions
• Monitor winter grains for crop growth stage, insect and disease
- assess crop for adequate stand
and plant vigor
Alfalfa & Hay:
• Monitor alfalfa seedings for weeds, insects & diseases.
• Check established alfalfa stands for alfalfa weevil, weed and
• Storage areas cleaned and ready to accept upcoming harvest?
• Check stand establishment of early plantings
• Gaps in row? Check for seed corn maggot, wireworm, seedling
blights, birds, seed placement issues?
Dairy Livestock Barn Fly Management:
• Sanitation, sanitation, sanitation – clean animal resting areas,
feed troughs, minimize source of moist organic matter i.e. fly breeding
areas in barn and in adjacent animal loafing yard
• Check water sources, drainage, roof gutters for leaks and potential
• Begin fly monitoring: install “3X5” index card fly speck monitoring
cards through out barn
• Order fly management materials: fly tapes, insecticide baits,
natural enemies (parasitoids)
• Note any repairs needed for recently used equipment: tractors,
tillage implements, planters, etc. as they are cleaned and serviced.
• Hay harvesting equipment ready?
• 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 Livestock
Phone: (518) 434-1690
Fax: (518) 426-3316