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Weekly Field Crops Pest Report 2006

June 22, 2006 Volume 5 Number 10

1. View from the Field

2. Be Ready for Potato Leafhopper Before Damage Occurs!

3. Soybean Aphid Monitoring

4. IPM for Stored Grain

5. How to Recognize Scab (Fusarium Head Blight) in Wheat

6. Soybean Rust Update

7. Growing Degree Days in NYS

8. Clipboard Checklist

9. Upcoming Meetings

10. Contact Information

View From The Field

Eastern NYS
Ken Wise, NYS IPM

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Keith Waldron-NYS IPM

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This week at the Cornell University Research Farm in Valatie alfalfa weevil tip feeding was on the decline. I also found 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. 

Potato leafhopper in alfalfa remains low at the Cornell University Research Farm in Valatie and SUNY Cobleskill Farm this week. While doing a scout training in Orange County this week a new seeding of alfalfa was nearing threshold for potato leafhopper. There were lot’s of annual broadleaf weeds present including annual ragweed, an alternate host for PLH. With this seasonal change from cool to mid-summer temperatures potato leafhopper populations have the potential to increase over the next several weeks. If you do not know what they look like, here is a picture I took on Monday:

Pea aphid populations are on the rise in alfalfa. These tiny insects are not typically an economic concern for NY forage alfalfa. One reason these aphids are not a problem for NY alfalfa is because they are considered “lunch” by many natural enemies including a variety of predators, parasitoids, and fungal pathogens.

I saw my first fireflies blinking this last weekend. Fireflies and corn rootworm have something in common. About the time you start to see seeing firefly activity each summer, corn rootworm larvae hatch from their overwintering egg stage and begin feeding on corn roots.

Stephen Hadcock and I set up out a soybean sentinel plot to monitor for Asian Soybean Rust and Soybean Aphids in Columbia County. We discovered a disease that appears to be bacterial blight in V2 stage soybean seedlings. Samples have been sent to Cornell’s Diagnostic Clinic for confirmation. I have not found soybean aphids yet in Eastern NYS.

Nancy Glazier in Western NYS reports that soybeans range from V1-V3 stage of growth. She states that 1 of 5 fields that were observed had very low infestation levels of soybean aphids.

Soybean aphids were observed on V2 stage soybeans at SBR sentinel site at Cornell's Musgrave Research farm in Poplar Ridge NY (central NY). Several reports of low numbers of soybean aphid on V2 stage soybeans. Soybean aphids observed at SBR sentinel site at Cornell's Musgrave Research farm in Poplar Ridge NY (Molly Smartwood), in Jefferson county (Mike Hunter), in Seneca county (John Mizro (ACS). Waterloo). SBA populations are at trace to low levels, typically 0-5 SBA per plant, all wingless. Highest number observed on an individual plant was 25 SBA. Jeff Miller reports the SBR sentinel plot in Oneida county is disease and soybean aphid free this week.

PLH numbers low in alfalfa at the NYS Ag Experiment Farm in Geneva (0-2 per 10 sweeps, 24 inch alfalfa), Musgrave Research farm (Aurora) Aurora farm (0-3 per 10 sweeps, 6 inch alfalfa). No PLH nymphs found at either location. Elson Shields suggests the recent thunderstorms may have delivered a bunch of migrating adults - i.e. watch fields closely.

Black cutworm and dingy cutworm problems have been reported this week on V4 stage corn. Cutworm larval sizes have ranged from 1/2 inch to 1+ inches. Fields affected had weed control issues. Dan Steward (WNYCMA) reports armyworm infestations in some western NY corn stands. Fields affected were planted into a rye cover crop that had a late April burn-down herbicide treatment.

Dairy Flies: The Cornell Veterinary Entomology Research crew reports a marked increase in house fly populations in/around dairy barns this week. Recent rains have contributed to the moist conditions favorable to creation of successful fly breeding habitat. Higher temperatures reduce the time required for house flies to develop from egg to adult. Watch for fly populations to increase. Timely intervention with sanitation will slow population build up. Stable fly populations appear to be relatively low at this time. House flies have a shorter life cycle (egg to adult) than stable flies so tend to build up to higher populations more quickly. Watch for possible increases in stable fly populations following movement of storm fronts as these insects can hitch rides on weather systems.

For animals on pasture - face fly populations are on the increase. Higher numbers of horse flies have also been observed.

Be Ready for Potato Leafhopper before the damage occurs!

Ken Wise, NYS IPM

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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 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 guides: IPM for Potato Leafhopper in Alfalfa

Soybean Aphid Monitoring

Keith Waldron-NYS IPM

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Soybean aphids (SBA) were observed on V2 stage soybeans at several NY locations this week (Aurora, Farmington, Geneva, Waterloo, and Watertown). Soybean aphids have not been observed in eastern NY so far this season. Individuals monitoring soybean rust sentinel sites have been asked to report presence and abundance of soybean aphids. This information is being added to the NY information for soybean rust / soybean aphid available on the National USDA PIPE website (www.sbrusa.net).

How much of an issue will SBA populations be in NY this year remains to be seen.

SBA threshold guideline - 250 per plant at or near R1.

This action threshold is based on an average of aphids per plant over 20-30 plants sampled throughout the field. Regular field visits are required to determine if aphid populations are increasing. Midwestern research has found that treating earlier than this threshold in most cases does not pay for itself.  But if you have aphids at flowering, the SBA population is increasing compared to the previous weeks count, no or insufficient numbers of natural enemies are present, or other limiting factors are present such as drought, the treatment of SBA may be warranted. Yield loss is due to pod abortion and once pods are gone, there is no recovery of yield other than getting seed a bit bigger. This recommendation has held up well over the past 4 years. 

Note: During early to mid-vegetative stages of soybean growth, economic benefit from insecticide application is not likely.  Plus, using an insecticide too early in the season may jeopardize the establishment of natural enemies in the field. When scouting the early vegetative stages of soybeans for soybean aphid, it is just as important to watch for the aphid’s natural enemies, including ladybugs, syrphid fly larvae, parasitic wasps, and fungal pathogens. We’ll highlight these biological control agents over the next several issues of the Pest Report, so stay tuned! 

Your observations will help document SBA presence, abundance, and help identify locations with potential concerns. If you wish to share your SBA observations send comments to Keith Waldron (jkw5@cornell.edu).  Information on date, location, average SBA population number, plant growth stage, and aphid form (winged or wingless) will be helpful. Feel free to include additional commentary such as presence of natural enemies, crop condition, other pests observed.

The USDA recommends the following protocol be used to monitor soybean aphids

  1. In sentinel plots, note the latitude and longitude with a GPS unit.

  2. 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 plot.  Identify the growth stage of 5 of the 20 plants.

  3. 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, examine the entire plant, including pods.  Spend no more than 30 sec to examine an individual plant.

  4. Count aphids per plant when they are below 250 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.

IPM for Stored Grain

Ken Wise, NYS IPM

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Wheat harvest time is approaching quickly. Will you be ready? Now would be a good time to prioritize management activities to prepare for your grain harvest. Number one priority? Sanitation - the key to keeping insect pests out of your stored grains. The following is a step by step method for IPM in stored grain:

  1. Clean grain handing equipment (augers, combines, wagons, scoops, and trucks).

  2. Clean inside the grain bin (remember to clean under the false floor). Mice, moths, weevils and much more can survive under the false floor.

  3. Clean around the outside of the grain bin. Mow weeds, and remove all spilled grain and debris 6 to 10 feet from around the grain bin. This will remove all habitats and minimize food sources of interest to potential grain bin pests including insects and rodents.

  4. Seal all cracks and crevices. Cracks are prime locations for insects to enter grain bins.

  5. Cover fans when they are not being used. Insects can enter the grain bin this way also.

  6. Use a registered sanitizing insecticide spray in and around the structure after cleaning.

  7. Never store new grain with old grain.

  8. Dry the grain bin before adding new grain. Insect pests need moisture to survive.

  9. Level the surface after filling the grain bin. Moisture accumulates in a grain peak.   Microbial activity in the wet area will heat up and attract secondary insect pests.

  10. Do not fill grain bin all the way to the top. Leave a few feet for aeration.

  11. Aerate the grain to at least the ambient temperature. The hotter the grain gets the faster insect   pests can develop. Stored grain insect pests development slows when the temperature falls below 500 F.

  12. Monitor grain for insect pests every 20 days from spring till fall and every 30 days in the winter.  

  13. If you discover an infestation of insect pests you may consider an insecticide application. Select   a NYS registered product for your stored grain. READ THE LABEL.

  14. Keep areas around grain bins mowed to limit rodent hiding places.

The following are common insect pests of stored grains: Common Insect Pest of Stored Grain, Granary weevil , Saw tooth grain beetle, Red flower beetle, Larger cabinet beetle , Lesser grain borer, Rice weevil, Indian-meal moth, Flat grain beetle, Angoumois grain moth, Confused flower beetle

How to Recognize Scab (Fusarium head blight) on Wheat

Ken Wise, NYS IPM

One of the most devastating diseases of wheat is Scab or also called “Fusarium head blight.” This disease infects the grain head at flowering. The disease builds up in corn, wheat and other grain residues. Research by Dr Bergstrom and Shields (Cornell) has discovered Fusarium spores are carried up into the atmosphere during the day and settle out across the landscape at night. If it rains at flowering and spores are present there is a good chance the grain will become infected with the disease. The first symptoms of Fusarium head blight occur shortly after flowering. Diseased wheat heads exhibit premature bleaching as the pathogen progresses. One or more spikelets located in the top, middle, or bottom of the head may be bleached. Over time, the premature bleaching of the spikelets may progress throughout the entire head. If the environment is warm and moist, aggregations of light pink/salmon colored spores may appear on the rachis and glumes of individual spikelets. Later in the season, bluish- black spherical bodies may appear on the surface of affected spikelets. As symptoms progress, the fungus colonizes the developing grain causing it to shrink and wrinkle inside the head. Often, the infected kernels have a rough, wilted appearance, ranging in color from pink, soft-gray, to light-brown.

Soybean Rust Update

Gary Bergstrom

Observation and Outlook - Disease  Last Modified: 06/22/06

Scouting has begun this week on 19 sentinel plots located in Cayuga, Chautauqua, Chemung, Chenango, Columbia, Genesee, Jefferson, Montgomery, Oneida, Onondaga, Ontario, Seneca, Tompkins, Wayne, and Wyoming Counties. See the New York Soybean Rust Information Center for more information. 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. To date, in 2006, soybean rust has been reported on kudzu in five counties in Alabama, 12 counties in Florida, and four counties in Georgia. Although rust was confirmed in a sentinel soybean plot in southeastern Florida, Florida officials feel that the overall spore production in the state is still very low. Currently, there are no known reports of rust on commercially planted soybean in 2006. Many of the southern states are experiencing hotter and drier than normal conditions reducing the likelihood of viable spore dispersal. A report regarding Mexico indicated that rust had occurred earlier in the year (winter season seed production) before any commercial soybeans were planted in Mexico or the U.S. There is no evidence to date suggesting that airborne spores originating in Mexico have resulted in soybean rust infection in Texas or other U.S. states. Last updated (June 21, 2006)

Growing Degree Days in NYS

Ken Wise NYS IPM

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Accumulated Growing Degree Days for March 1 to June 14

Location

Base 48 F

Base 50 F

Batavia

674

572*

Chazy

742

641

Clifton Park

1011

890*

Geneva

785

672

Ithaca

709

602*

Mexico

734

636*

Prattsburg

550

460*Much data missing

Redhook

1099

972

*indicates missing data

Source: NEWA

Clipboard Checklist

Keith Waldron-NYS IPM

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General:
* Update crop records by field, including pesticides used, nutrient inputs including manure, growth and development observations, other comments, etc.
        - Record hay crop yields by field and quality by storage facility; take samples for forage analysis
        - Inventory remaining corn silage and allocate forages for summer feeding
* Clean and prepare storage areas for small grain harvest
* Adjust pasture rotation, check fencing, water sources

* Make plans for fun Fourth of July activity

Corn:
* Monitor fields for crop growth and condition, seed corn maggot, wireworm, cutworm, seedling blights, birds, armyworm
* Evaluate weeds and adjust post emergence treatments
- note presence of triazine resistant annual broadleaf weeds
-Cultivate or treat if necessary
* Pre-Nitrogen Sidedress Soil Test and apply sidedress as needed

Small Grains:
* Monitor for crop growth and condition, insect (cereal leaf beetle, armyworm, European corn borer) and disease problems Fusrium (scab) and other head and leaf blights)

Alfalfa & Hay:
* Monitor alfalfa seedings for crop growth and condition, weeds, potato leafhopper & diseases.
* Check established alfalfa stands for potato leafhopper, weed and disease problems
- Take alfalfa stand counts while regrowth is short (if not done earlier in the season)

Soybeans:
* Check stand establishment, crop growth and condition, weed control
* Evaluate stand for uniformity,seed corn maggot, wireworm, seedling blights, birds, planter problems, drainage issues
* Monitor for soybean aphid, soybean rust, presence of natural enemies

Dairy Livestock Barn Fly Management:
Barn Areas:
* 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 overspill
* Collect and evaluate "3X5" index card fly speck monitoring cards. Record results for future comparisons. Replace with new cards
* Evaluate animals for stable fly harassment (10 stable flies per animal)
* Replace fly sticky tapes as needed, check insecticide bait traps
Pasture:
* Check condition of pastures and animals on pastures
- Evaluate need for face fly and stable fly control measures
- Insecticidal ear tags for heifers (non-lactating animals) on pasture
- Adjust pasture rotation, check fencing, water sources

Equipment:
* Note any repairs needed for recently used equipment: tractors, harvest equipment and wagons, etc. as they are cleaned and serviced.
* Calibrate manure spreaders - maintain records on amount spread per field
* Prepare small grain combining equipment or arrange for custom combining

Upcoming Events

July 6 - Thursday - NY Weed Science Field Day, Valatie Research Farm. Valatie, NY: 9:30 am- Noon

July 6 - Thursday - Seed Growers' Field Day, NYSIP Foundation Seed Barn, Ithaca, NY (791 Dryden Road, Route 366)

July 12 - Wednesday - NY Weed Science Field Day, Robert B. Musgrave Research Farm, Aurora, NY (Poplar Ridge Road, connects 90 and 34B) 11 am – 1 pm Chicken BBQ, Tour 1:00pm to 5:00pm.

July 13 - Thursday - NY Weed Science Field Day, H. C. Thompson Research Farm, Freeville, NY (10 miles Northeast of Ithaca, Fall Creek Road, Rt. 366 extension) 8:00 am – Noon

July 20 - Thursday - Aurora Field Day, Robert B. Musgrave Research Farm, Aurora, NY 9:00am – 3:30pm

Contact Information

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Julie Stavisky: IPM Area Educator, Livestock and Field Crops, Western NY
Phone: (315) 331-8415
Fax: (315) 331-8411
Email: js38@cornell.edu

Keith Waldron: NYS Livestock and Field Crops IPM Coordinator
Phone: (315) 787 - 2432
Fax: (315) 787-2360
Email: jkw5@cornell.edu

Ken Wise: Eastern NYS IPM Area Educator: Field Crops and Livestock
Phone: (518) 434-1690
Fax: (518) 426-3316
Email: klw24@cornell.edu