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Weekly Field Crops Pest Report 2008

June 12, 2008                 Volume 7 Number 9

1. View from the Field

2. Weather Outlook

3. Black Cutworm in Field Corn

4. Soybean Emergence and Stand Counts

5. Sampling for Potato Leafhopper in Alfalfa

6. NYS Soybean Rust Update

7. Growing Degree Days in NYS

8. Clipboard Checklist

9. Up Coming Events

10. Contact Information

View from the Field

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Eastern NYS-Ken Wise

At the SUNY Cobleskill farm alfalfa weevil was at threshold on alfalfa re-growth. There were many larvae, and many were still small, ranging from 1st to 3rd instar. Remember, the action threshold for alfalfa weevil on 2nd cutting is 50 percent tip feeding with small larvae present. There was also potato leafhopper present at low numbers in the fields.  In a corn seed planting depth research trial at SUNY Cobleskill being conducted by Kevin Ganoe (Central NY Dairy and Field Crop Team), all of the corn seed planted at 1 inch or less was picked out and consumed by crows. The deepest planted plots had no bird damage.  

Birds removed all shallow planted corn seed

Tom Kilcer (Capital District) reports a few corn fields over threshold for black cutworm.  Patricia Westenbroek ( Sullivan County) reports that black cutworm has been an issue in a few field. For more information on black cutworm view the article below.

Western NYS and Finger Lakes Region

Mike Stanyard (Northwest NY Dairy and Field Crop Team) reports heavy infestations of common armyworm in winter wheat. Infestation levels ranged form 4 to 15 larvae per square foot. Remember that armyworm can go undetected because most of the damage they do is in the last larval instar. Keep a close eye on your small grains, corn and grass fields for armyworm. Mike Stanyard also reports some corn fields were over threshold for black cutworm. He is also starting to see cereal leaf beetle in some oat fields. Dean Sprague (Allegany, Cattaraugus, and Chautauqua Counties) reports that some wheat and oat fields had armyworm damage. Mike Dennis ( Seneca County) reports finding potato leafhoppers. Keith Waldron reports fireflies observed in Ontario county. These insects are typically seen about the same time of year that corn rootworm eggs begin to hatch.

Weather Outlook

Drew Montreui
NOAA NE regional Climate Center, Cornell University

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Weather Outlook 6.12.08

The past week saw very hot weather with temperatures region wide running well above normal. Almost the entire state ended up 9 to 15 degrees warmer than average. Precipitation was hard to come by in Central and Western New York, where generally less than half an inch fell. Rain was more abundant further east, where 1 to 3 inches fell.

Base 50 Growing Degree Days accumulated 150-200 across most of the state, with the mountain areas receiving 100-150. For the season, this puts most areas between 300 and 500, the exception again being the Adirondacks and Catskills where there have been 200-400. Compared to last year, this puts most areas within 75 growing degree days on either side of last year. Southeastern New York is the exception, which is 75 to 150 Growing Degree Days behind last year. The entire state is now running about 3 to 7 calendar days above normal.


Another pattern shift is in store for the Northeast over the course of the next week as we shift from above average temperatures Friday and Saturday, to below average temperatures by next week. With a high pressure centered off the Southeast Coast tomorrow [Friday], south-westerly winds will bring hot, humid weather back on Friday, when highs across the region could approach 90 with a couple pop-up thunderstorms. Lows Saturday morning will generally be in the mid to upper 60s. A cold front will move from west to east with a better chance for thunderstorms on Saturday. With highs in the mid 80s and the humidity up, some of those storms could again be severe. Drier weather will come in Sunday, with lows will be in the upper 50s to near 60 and highs will generally be near 80. Another front will come through on Monday, bringing another chance for rain. Lows will be near 60 and highs in the mid to upper 70s. The area of low pressure associated with this front will then park itself over southeastern Canada. This will keep showers possible on Tuesday, with a lesser chance on Wednesday. Highs will only be in the low 70s Tuesday and many places will not get above 70 on Wednesday. Low temperatures wont see as drastic a cool down, with lows in the low to mid 50s both days. Precipitation amounts look to generally be near or slightly below 1, with the higher amounts typically in the west. This cool pattern looks to continue into the 8-14 day period, with temperatures below to well below normal with average precipitation.

Black Cutworm in Field Corn

Ken Wise

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A few fields in Eastern NYS were reported hit by infestations of black cutworm this last week.

The cutworm adult moths ride weather fronts that carry them from the south to the Northeast.  Weedy grasses and winter annual broadleaves (especially chickweed) are favorite targets. If cutworm moths lay eggs in the field and the field is treated with an herbicide, hatching cutworm larvae bail off the dying weeds and look for greener food sources such as emerging corn seedlings. Cutworms can be an annual problem in some fields; particularly those with a history of poor weed control or with low wet areas in the field. Field margins, especially those next to ditch banks, grassy lanes, and hay fields are potential sites for infestation. Doing an early season plant population count is a good way to check corn fields for cutworm damage and other corn emergence problems.

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. During the day larvae burrow into the soil next to the corn plant. These larvae curl into a C-shape when disturbed. Symptoms of damage are leaf feeding, irregular holes in stems, notched and cut or missing plants. No-till fields and those with a lot of grass weeds are at particular risk to black cutworm. Monitor fields to find cutworm larvae when they are less than 1/2 inch long. If there are sufficient numbers and if 5% or more plants have been cut, an insecticide could be justified. Treat only the affected area and a 20 to 40-foot border around the infestation. Rarely does a whole field need to be treated for cutworm. Larger cutworm larvae, greater than 1/2 inch long, are much more difficult to control. If the majority of cutworm larvae are 1/2 inch long or larger their damage is already done. These large larvae are also more tolerant of insecticides, reducing the effectiveness and economic viability of this option. Check out our on-line publication, Black Cutworm in Field Corn Management Guide.

Soybean Emergence and Stand Counts

Julie Dennis

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Soybeans seem to have sprung out of the ground overnight during this weeks heat wave, so it will soon be time to assess soybean stands. The to-do list includes estimating plant populations and investigating the cause of missing plants in the rows. These activities will be conducted at soybean TAg Team meetings occurring over the next couple of weeks.

The following table summarizes a method for estimating plant populations. Count the number of plants in the given length of row based on the row spacing, and then add 3 zeros. (For example, if 165 plants are counted, your estimated plant population is 165,000). Repeat this for the number of rows in your planter or drill, and repeat in 2 more areas of the field.

If the row width is:(inches)
Then measure this length of row:
74 feet, 8 inches
34 feet, 10 inches
26 feet, 2 inches
17 feet, 5 inches
16 feet, 4 inches
14 feet, 6 inches

When skips are seen in the rows, it is time to do some digging. Are seeds planted too deep such that plants are still emerging? Was the planter or drill acting up? Are damaged seeds or seedlings seen? If seeds are mushy or rotten, a seed or seedling blight might be the problem. See Kens article for detailed descriptions of disease problems in soybean seedlings in the May 29th issue.

If seeds, stems, or roots show signs of feeding injury, the usual suspects are seed corn maggot, wireworm, or white grub. Risk from seed corn maggot is greatest if there is high organic matter on the soil surface, from crop residue or manure, for example. Wireworm and grub threats are usually greatest following a grass or pasture sod.

Stand assessment information gathered this year will help guide decisions about management that may be warranted in future years.

Sampling for Potato Leafhopper in Alfalfa

Ken Wise

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Scouting alfalfa fields is the key to early detection of potato leafhopper infestations. Use a 15-inch diameter sweep net to determine the potential risk a potato leafhopper infestation may pose to your alfalfa. Scouting for potato leafhopper starts after the first cutting of alfalfa (about the first part of June) till the first fall frost. You will want to use a potato leafhopper sequential sampling plan to determine if an infestation requires management or not. The first thing to do is determine the height of your alfalfa. Smaller plants are more vulnerable to potato leafhopper; thus there are different action thresholds for different heights of alfalfa. The second thing you will need to know is how to sample for potato leafhopper. A sample consists of a set of 10 sweeps of the net. A sweep is one pass in front of you as you walk through the alfalfa. The return swing is counted as another sweep. Sequential sampling reduces the time spent in each field and tells you whether to treat (management action) or not treat (no management action). Sequential sampling is particularly helpful in minimizing time required to make a management decision in situations where PLH populations are very high or very low. Use the following chart to determine potato leafhopper infestation levels.

N= No management needed at this time
T= Management needed as soon as possible    

Write down the number of potato leafhoppers for each sample taken on the card. Add each sample to the next, keeping a running total of potato leafhoppers. You will need to take at least 3 samples using the sequential sampling method. On the sequential sampling card N is defined as no treatment (no management) needed at this time and T is defined as treatment (management) needed within in a week. If the sample is smaller than the N number stop and scout 7 days later. If the number of leafhoppers is larger than the T number then management action needs to be taken within a week. If the number of potato leafhoppers fall between N and T then continue and take the next sample till a decision can be determined. A guide with a printable version of the sequential sampling chart can be found in our online publication, Potato Leafhopper on Alfalfa Management Guide.

NYS Soybean Rust Update

Gary Bergstrom
Cornell Plant Pathology

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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

Growing Degree Days in NYS

Ken Wise

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As of March 1 -  June 19, 2007

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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Clipboard checklist


* 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).

* Storage areas cleaned and ready to accept upcoming harvest?


* 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)


* Keep areas around storage bins and silos clean and mowed


* 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.

Up Coming Events

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Corn and Alfalfa Field Day
*June 18 at 12:30pm 3:30pm
At the SUNY Cobleskill Farm
Warnerville Cutoff Road, between Rt 7 and Rt 10 just West of Cobleskill, NY

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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Julie Dennis: IPM Area Educator, Livestock and Field Crops, Western NY
Phone: (315) 252-5440

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