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Weekly Field Crops Pest Report 2008

June 19, 2008                 Volume 7 Number 10

1. View from the Field

2. Weather Outlook 6/19/08

3. Be Ready for Potato Leafhopper before the damage occurs!

4. Not too Early to think about Stored Grain Pests

5. Soybean aphids – quiet so far

6. Which is Corn Rootworm?

7. NYS 2008 Asian Soybean Rust Status

8. Alfalfa Weevil Prediction for NYS – the end is near?

9. Clipboard Checklist

10. Upcoming Meetings

11. Contact Information

View from the Field

Ken Wise

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Message from Julie Dennis

Julie Dennis will not be a part of the team of regular contributors to the NYS IPM Weekly Field Crop Pest Report for the remainder of the 2008 season.  You may see an occasional article written by her “recycled” from past seasons; however she won’t be available to answer specific questions.  Look for her return to her regular NYS IPM activities this fall, and her return to the Pest Report team in the 2009 season.

Eastern and Western NYS

True Armyworm is the pest of the week. Several extension educators across the state have see armyworm levels from minor infestations to well over threshold levels in corn and winter wheat. Keep a close eye on small grains, pasture, grass hay, and corn. True armyworm larvae appear smooth, cylindrical, and pale green to brownish when they are still small. Mature larvae are smooth and marked with two orange, white-bordered strips on each side. True armyworm ranges in size from 1/8 inch to 1.5 inches long. Here is a website with a photo of armyworm: Armyworm photo. For an article on armyworm management please view this site: Armyworm Article

Black Cutworm has also been an issue over the last few weeks. Several Extension educators across the NYS have reported cutworm damage in corn fields. Black cutworm larvae vary in color from light gray to black with a pale brown to black head. Larvae have a greasy, shiny appearance with coarse granules present over their body. For more information on black cutworm view last weeks article: Black Cutworm in Corn Article

Mike Stanyard and Brian Aldrich report cereal leaf beetle over threshold in small grain fields in Western NYS. Small black slug-like larvae emerge from the egg and reach about a 1/4 inch long. Larvae feed on the leaf surface, leaving long narrow white strips between the veins. The adults are 3/16 inch long with metallic bluish-black head and wing covers.

I discovered alfalfa weevil over threshold in alfalfa re-growth in Julie Hansen’s trial plots at SUNY Cobleskill late last week. Tip feeding was at 50% and there were still a lot of small larvae. These plots were sprayed with Warrior. While there is still a mix of small and larger larvae alfalfa weevil in fields I have been looking at scouting should soon end. I am starting to find alfalfa weevil cocoons in a few leaves. The following picture shows what they look like:

This is a good indication that alfalfa weevil feeding by larvae will soon end. Once they pupate (create a cocoon) the leaf feeding by larvae is over. 

Currently, potato leafhopper can be found in alfalfa at low levels statewide. Remember, this insect pest infestation levels and increase very quickly. Keep a close eye on this and scout fields weekly.

Dr. Russ Hahn (Crops and Soil Science) suggest that if you have not yet sprayed your weeds in fields of Round-up Ready Corn you should do it soon. Remember weeds should be controlled by the corn’s 4th leaf stage.

Weather Outlook 6/19/08

Drew Montreui
NOAA NE Regional Climate Center, Cornell University

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Temperatures across the state last week ran near or just above normal, fueled mostly by a very warm start to the week. Nearly all of the state ended up about 3 degrees above normal, with some isolated pockets that were as much as 6 degrees warmer than average. Rainfall was scarce across Northern New York, where generally less than ½” fell, with some places recording no rain. Areas along and south of Interstate 90 generally saw roughly an inch of rain.

Base 50 Growing Degree Days saw moderate accumulation this past week, with most areas picking up 100 to 150, with slightly more towards New York City. This puts the yearly totals between 500 and 700 for most areas, with 300-500 in the higher elevations of New York. Compared to normal levels, this puts much of the state as much as 10 days ahead of normal values. However, compared to last year, most places are between a ½ week to a week behind last year.


The area of low pressure that has been giving us cool, wet weather the past few days is forecasted to finally lift out of our region, allowing a return to seasonable temperatures. As this low departs, high pressure to our south will begin to influence our weather tomorrow and Saturday. On Saturday, highs will generally be in the mid 70’s with lows in the mid 50’s. There will likely be some showers and storms around, with a better chance on Sunday as a front comes through. Highs and lows Sunday will each be a few degrees warmer than Saturday. It then appears that this front will stall to our east, with another low sitting over us. However, this doesn’t look like it will give us cold weather like this week. Highs Monday will be in the low to mid 70’s, with mid to upper 70’s Tuesday. Lows will be near 60 both days. With the front and low nearby, occasional rain is likely. As this system departs, highs Wednesday will likely be near 80 with a much lower chance of rain. Most areas during this time period stand a chance at picking up between 1” and 1 1/2” of rain.

Our near normal temperatures look to continue into the 8-14 day period with no big warm ups or cool downs in sight. However, it looks as if precipitation during this time will fall to below average values.

Be Ready for Potato Leafhopper before the damage occurs!

Ken Wise

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As temperatures increase and weather fronts roll through NY, so does the risk of potato leafhopper populations reaching levels damaging to alfalfa yields and quality. Do you know what to do if a field reaches an action threshold for potato leafhopper in alfalfa? Here are the management options for potato leafhopper in alfalfa!

Option 1: Early Harvest

You can harvest the alfalfa early to control potato leafhoppers if the field is within a week to ten days of a scheduled harvest. By harvesting the alfalfa early, you’ll prevent potato leafhopper from reaching infestation levels that can cause yield and quality loss to the forage. Make sure that the whole field is harvested at the same time. If a field is not clean harvested then the alfalfa that has not been cut will serve as a refuge for potato leafhoppers and can re-infest; thus severely damaging alfalfa re-growth.

Option 2: Use an Insecticide

To protect yield and health of new seedings and established alfalfa, insecticide control can be warranted when a field is not within a week of harvest. For selection of an insecticide consult the current issue of Cornell Guide for Integrated Field Crop Management. Remember to read the label and be aware of blooms, bees and the days until harvest restrictions.

Option 3: Plant Potato Leafhopper Resistant Alfalfa

A third option for control is planting potato leafhopper resistant alfalfa. Obviously, it is a little late for this season’s crop but something to consider for future seedings. Research has shown that potato leafhopper resistant alfalfa is consistently higher in quality than susceptible alfalfa varieties with or without potato leafhopper pressure. PLH resistant varieties yields are comparable and generally better than susceptible varieties when PLH are present. A bonus benefit is that currently available alfalfa varieties with PLH resistance have come down in price over the past several years.

For management information check our on-line IPM guide, Potato Leafhopper on Alfalfa Management Guide

Not too Early to think about Stored Grain Pests

Keith Waldron

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It won’t be long before wheat heads begin to lighten in color indicating harvest time is near. This year’s strong commodity prices prompt much anticipation for a profitable harvest. With that in mind, it is not too early to begin preparing for harvest and checking the readiness of your on-farm storage bins. To maintain the profits a good yield can bring, make and follow a plan to protect the grain while in storage. Remember: Grain storage will not improve grain quality. However, proper management of grain during storage will protect the quality present at harvest.

The IPM approach for stored grain protection includes a combination of sanitation, well-sealed bins, frequent monitoring for temperature and insect populations, aeration to cool grain in the fall, and pest management treatments as needed. Stored grain management begins with "an ounce of prevention". This article will highlight some steps one can take now to protect stored grain before it is harvested. The following pre-harvest information was "gleaned" whole or in part from Stored Grain IPM information from Oklahoma State University Stored Products Research & Education Center and Purdue University. Source URL's are provided at end of this article.

Insect infestations are the more common stored grain pest issues one might encounter. Insect infested grain can be docked at time of sale. Most common grain bin insect problems can be traced back to infestations in previously stored material, cracked grain and grain fines and trash. The key to prevention is SANITATION - clean out the bin every time it is emptied. How clean? If you can tell what was stored in the bin the last time it was used, it needs more cleaning. In addition to insects, birds and rodents are also attracted to left over and spilled grain. Lights mounted on or in close proximity to grain bins may attract unwanted stored grain insects.

Who might the likely insect pests be? This could be the subject for a future article. In the meantime the following extension factsheets provide information to help identify the insects you may find as you clean out your storage bins: Management of Stored Grain Insects, Part II. Identification and Sampling of Stored Grain Insects and Principal Stored Grain Insect Pests of Indiana.

The following sanitation practices are recommended for managing empty storage bins.
* Clean harvest and transportation machines before harvest.
* Repair all grain handling equipment before harvest and keep it in good condition.
* Seal unloading auger, auger tube opening, and side door openings before harvest
* Empty storage structures of old grain. The new crop should never be stored on top of old grain.
* Remove and destroy any grain from beneath, around or near the bin area. Sweep and vacuum the floors, false floors, and walls inside empty bins to remove old grain and debris. This debris usually contains insect eggs, larvae, pupae, and/or adults, all ready to infest the new grain. A shop vacuum, broom and scoop are very useful in a cleanup job, and all collected material should be discarded properly.
* Check fan boxes for possible grain pests.
* Remove any spilled grain outside the storage structure.
* Mow / remove weeds at least 10 feet around the bins.
* Check and clean or replace rodent traps.
* Check the integrity of screens and porcupine wires to limit bird entry and roosting.
* For additional protection against infestation, the inside and outside surfaces, foundations and floor of a storage facility can be sprayed with residual insecticide, four to six weeks prior to harvest, to kill any insects that were not removed during cleaning and those that migrate into the bin.
* Establish a written sanitation schedule, keep appropriate records

Bin Sealing
Roof leaks commonly lead to columns of spoiled grain. Check for these leaks by looking for light coming into the bin. Moisture coming into the bin through the seal between the bin and concrete will cause spoilage around the perimeter of the bin at the base. Check the seal since sealants do deteriorate. Water will run away from the seal at the base of the bin wall if the concrete is sloped away from the bin. Also check the seals around the doors and hatches.

Besides keeping grain dry, grain storages should be well sealed for two other basic reasons:

(1) to minimize grain insect entry problems into base and sidewall grain, and
(2) to minimize leakage should fumigants be used.

In addition, improved insect kill (efficacy), tighter sealed structures require lower dosage rates, which reduce the cost of future fumigations and cover the cost for the sealing materials and labor.
When clean grain is transferred into a clean, sanitized structure with base and sidewalls well sealed, the main insect infestation and population growth should be on the grain surface in the structure headspace. Permanently sealing all non-functional base, sidewall and roof openings is the first priority of sealing storages. The second sealing priority is to seal functional openings at all times during the year when the component is not being used. More information on bin sealing is available on the SPREC Web site.

Source of the above stored grain pest management information: Oklahoma State University Stored Products Research & Education Center Newsletter - Spring 2004 and Purdue's Stored Product Pest factsheet.

Soybean aphids – quiet so far

Keith Waldron

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Soybean planting is nearing completion in many areas of the state with some fields just in early trifoliate stages. So far no soybean aphid reports have surfaced hopefully indicating we are still ahead of that curve.

The bulk of weekly scouting for SBA should begin when soybean plants are in the late vegetative (pre-reproductive) to early reproductive (i.e. flowering) growth stages. Of course it is never too early to begin monitoring for this pest and it is worth a look for them as you check soybean fields for plant growth and development, plant population and weed presence and information to time management decisions. Monitoring soybeans for soybean aphids is easy. The following protocol is recommended:
1. Select 20 plants at random, each from a different location (not consecutive down the row) so that the 20 plant-sample is representative of the entire field.  Identify the growth stage of 5 of the 20 plants.
2. Examine the entire plant beginning with the growing point (newest trifoliate) for soybean aphids.  If plants are in vegetative growth (no pods or flowers) generally only the growing point needs to be examined.  As flowering and pod set occur later this season, examine the entire plant, including pods.  Spend no more than 30 sec to examine an individual plant.
3. Count aphids per plant when they are below 250 (the economic threshold) and estimate aphid density when aphid numbers exceed 250. Apterous (wingless) aphids are assumed to be present. Note whether alate (winged) aphids were also observed. Notes could also be used to indicate if any predators or parasitized aphids (mummies) are present or other such noteworthy observations on crop growth and field condition.

Note: Current research data suggests that treatment during vegetative soybean growth stage is not likely to result in an economic return.  In most cases, weekly scouting will be necessary for 8-10 weeks.

We will continue to keep close tabs on potential soybean pest problems and share any pertinent updates in future weekly pest reports. A national perspective on soybean aphid and soybean rust information can be found at the USDA Public PIPE website.

Which is Corn Rootworm?

Ken Wise

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Have you ever gotten western corn rootworm confused with the striped cucumber beetle? Do you know the difference between corn rootworm and striped cucumber beetle? Striped Cucumber Beetle and Western Corn Rootworm look similar but are two different species of insects.

Striped Cucumber Beetle, Acalymma vittatum
The Striped Cucumber Beetle adult is about 1/4 inch long and the upper body surface is about equal black and yellow, the folded wing covers forming three longitudinal black stripes. The adult beetle starts appearing on several vegetable crops starting in mid-June.

Western Corn Rootworm, Diabrotica virgifera virgifera
Female Western Corn Rootworm is 5/16 inches long with three black strips alternating with yellow. Male Western Corn Rootworm is mostly black with a small area on the poster end that is yellow-green. Adults start appearing in mid to late July.

Female Western Corn Rootworm
Striped Cucumber Beetle
Insect Markings
Stripes are less distinctive and do not extend to the tip of the abdomen
Both sexes have stripes, are clearly defined, and extend to the tip of the abdomen.
Insect size
5/16 inches long
1/4 inch long
Host range
Primarily Corn
Secondary Cucurbits
Primarily Cucurbits
Secondary beans, corn, potatoes and other crops
Life cycle
1. Over-winter as eggs in the soil in the field
2. Eggs hatch and larvae feed on the corn roots starting in late May
3. Adults emerge at time of corn pollination. Males emerge first
4. Adults lay eggs in cornfields mid to late pollination
5. Adults die, eggs overwinter
1. Over-winter as adults in woodland litter or in the soil.
2. Lay eggs at the base of the plant in mid-June through mid-July
3. Larvae develop for 2 to 4 weeks on the roots, pupate in the soil.
4. Adults appear in early to mid-August
5. Adults produced this season overwinter

Learn more about the differences between Western Corn Rootworm and Striped Cucumber Beetle:
Cucumber Beetles, Corn Rootworms, and Bacterial Wilt in Cucurbits

NYS 2008 Asian Soybean Rust Status

Gary Bergstrom

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Sentinel plots in New York State are currently being established in the following counties: Cayuga, Chautauqua, Chemung, Columbia, Cortland, Jefferson, Lewis, Livingston, Madison, Niagara, Oneida, Ontario, Schoharie, Seneca, Steuben and Wayne. We will continue to provide disease updates on these plots as the growing season progresses.

Since the beginning of 2008, soybean rust has been reported on kudzu in one county in Alabama; ten counties in Florida (two of these counties had reports on coral bean and snap bean); three counties in Louisiana; one county in Mississippi, and three counties in Texas. Reported infected kudzu sites in many counties have been destroyed. Rust was also reported in three states (5 municipalities) in Mexico on yam bean and soybean. These too have been destroyed or are no longer active, except for the recent find in Chiapas. Soybean sentinel plots have been established throughout the Gulf Coast region, and in many parts of the lower Midwest.(Updated June 10, 2008 )

NY State Soybean Rust Hotline: 607-255-7850

NYS Soybean Rust Website

USDA Soybean Rust Website

Alfalfa Weevil Prediction for NYS – the end is near?

Ken Wise

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Current accumulated degree day data indicates alfalfa weevil populations are approaching maturity and should not be an issue much longer this season.  However…. Alfalfa weevil damage continues to be reported on alfalfa re-growth in some areas of NYS. Lingering concerns over alfalfa weevil are the result of delayed population development affected by the cooler temperatures many areas experienced earlier this season. So in addition to monitoring for PLH on alfalfa re-growth, also continue monitoring for signs of weevil feeding.  See: IPM for Alfalfa Weevil for more information on monitoring late season alfalfa weevil.

As of March 1 -  June 18, 2008

Base 48 F
Base 50 F
Clifton Springs
*Missing data 
Source: Network for Environment & Weather Awareness

Alfalfa Weevil Degree Day Development Map

Growing degree Days for peak (50%) Occurrence of Alfalfa Weevil growth stage:

Stage or Event
Accumulated growing degree days (48F base temperature)
Eggs hatch
Instar 1
Instar 2
Instar 3
Instar 4
Adult Emergence

 (Note: for alfalfa weevil predictions use Base Temp of 48F)

Clipboard Checklist

Keith Waldron

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* Emergency contact information ("911", local hospital, Chem. Spill emergency contact, other?) posted in central posting area

* Maintain crop records by field, including variety, planting date, pesticides used, nutrient inputs including manure, etc.

* Watch for winter annual and other early season weeds, any patches of herbicide resistant weeds?

Field Corn:

* Determine plant populations, make notes on emergence problems, growth stage

* Gaps in row? Check for seed corn maggot, wireworm, cutworm, armyworm, seedling blights, birds, seed placement issues

* Check no-till fields/fields with high residue or weeds for slug damage, cutworm, armyworm

* Monitor for weeds, note presence of "who", "how many" and "where"

* Check herbicide resistant corn fields for herbicide resistant soybean

* Adjust post emergence weed control actions

Small Grains:

* Monitor winter grains for crop stage (flag leaf?), insect problems (cereal leaf beetle, armyworm) and foliar / head diseases

* Evaluate crop for adequate stand and plant vigor

Alfalfa & Hay:

* Monitor alfalfa seedings for weeds, insects & diseases.

* Check regrowth of established alfalfa stands for alfalfa weevil, potato leafhopper, weed and disease problems.

* Check windrows of recently harvested alfalfa for signs of alfalfa weevil feeding damage and weevil life stage (instar , cocoon).


* Evaluate stand emergence - seedling blights, seed corn maggot, weed assessment, soybean aphid

* Check herbicide resistant soybean fields for herbicide resistant corn

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 waterers, drainage, roof gutters for leaks and potential overspill

* 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)

* Continue release of purchased natural enemies (fly attacking parasitoids)

Dairy Livestock Pasture Fly Management:

* Begin monitoring for face fly, horn fly, and stable fly populations

* Check water sources, forage available on pastures

* Check areas near watering troughs, outside feed bunks for evidence of fly breeding. clean as necessary and / or possible


* Keep areas around storage bins and silos clean and mowed

* Evaluate storage bin condition, clean as necessary preparing bins to accept upcoming harvest


* Note any repairs needed for recently used equipment: tractors, tillage implements, planters, etc. as they are cleaned and serviced.

* Service corn and soybean planter as needed. alfalfa harvesting equipment, and tillage implements

* Calibrate manure spreaders - maintain records on amount spread per field

Emergency responder information on pesticide spills and accidents CHEMTREC:  800-424-9300

For pesticide information:
National Pesticide Information Center: 800-858-7378

To Report Oil and Hazardous Material Spills in New York State_NYS Department of Environmental Conservation Spill Response:_800-457-7362 (in NYS)_518-457-7362 (outside NYS)

Poison Control Centers: Poison Control Centers nationwide: 800-222-1222

If you are unable to reach a Poison Control Center or obtain the information your doctor needs, the office of the NYS Pesticide Coordinator at Cornell University, 607-255-1866, may be able to assist you in obtaining such information.

Upcoming Meetings

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Seed Growers Field Day
*Tuesday July 8
NYSIP Foundation Seed Barn
Cornell University, Ithaca, NY

Weed Science Field Days
*Wednesday, July 9, 2008
Valatie Research Farm
9:30 am - Noon
Valatie, NY ( State Farm Road off Route 9 just north of Valatie)

*Wednesday, July 16, 2008
Robert B. Musgrave Research Farm
1:30 pm - 5 pm
Aurora, NY ( Poplar Ridge Road, connects 90 and 34B)

Aurora Field Day
Wednesday, July 23, 2008
Robert B. Musgrave Research Farm
Aurora, NY ( Poplar Ridge Road, Connects 90 and 34B)

Contact Information

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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