Skip to main content
link to field crops section
->Home > fieldcrops > tag > pestrpt > pestrpt10

Weekly Field Crops Pest Report 2010

May 10, 2010      Volume 9 Number 3

1. View from the Field

2. Weather Update, May 6, 2010

3. Soilborne Viruses in Winter Wheat

4. Fungicide Options for Wheat

5. Beware of using the same insecticide seed treatments on all your corn fields!

6. Lady Beetle of the Week. Fourteen Spotted Lady Beetle

7. Alfalfa Weevil Scouting/ Management and Growing Degree Days

8. Clipboard Checklist

9. Mark Your Calendars

10. Contact Information

View from the Field

return to top

Alfalfa weevil adults were readily found in alfalfa fields across the NY this week. In some areas 1st instar larvae were discovered. Once larvae are present you should start finding the "shot holes" in the leaflets. For more information on alfalfa weevil see article below.  

Powdery Mildew has been discovered on wheat in a few areas in Western and Eastern NY. Powdery mildew forms a white to gray, fungal coating on the above-ground parts of the wheat plant. Lower leaves are usually the most severely infected because of the high humidity in the lower canopy. As disease lesions age, small black fruiting bodies (cleistothecia) develop with in white infected areas. Powdery mildew is favored by wet and humid days with moderate temperatures of 600 F or above. Powdery mildew is disseminated by airborne spores.

A few cereal leaf beetle adults were found this week on cereal grains in Western NY. Adults of the cereal leaf beetle are 3/16 of an inch long, and their wing covers are a metallic bluish black color, while their legs and front sections are reddish. More to come on this pest next week!

Many areas around the state reporting planting, crop growth and development up to 10 days ahead of this time last year.

Weather Update, May 6, 2010

Jessica Rennells
Northeast Climate Center, Cornell University

return to top

Last week the entire state had above normal temperatures.  The Great Lakes and Finger Lakes regions and part of the Catskills and Hudson Valley were 9-12degrees above normal.  The rest of the state was 6-9 degrees above normal. Most of the state had .01 to half an inch of precipitation.  Part of the Mohawk Valley and the northern corner of the state had half to one inch.

The base 50 Growing Degree Days ranged from 25-100.  The great Lakes region and the southern Hudson Valley had 75-100 GDDs. The Adirondacks had 25-50 GDDs.    Most of the state ranges from 3 days to 2 weeks ahead of last year.  A portion of the Catskills is 3 days behind last year. The entire state is ahead of normal, and a majority of the state is 2weeks ahead of normal.  St. Lawrence County and the capital region are 3-10 days ahead of normal. 

Today's highs will range from the mid 50s to some low70s.  Tonight's lows will range from the upper 20s to mid 40s.  Friday will range from the mid 50s to near 70.  Friday night will range from the upper 30s to low 50s.  Showers will move in to western NY.  Saturday will have highs in the mid 50s to near 70 near the coast, and lows ranging in the 50s.  There will be rain throughout the state brought by a low pressure system.  Sunday we'll have highs only in the upper 40s and 50s with lows in the upper 30s and low 40s.  There's a chance of scattered precipitation for the northernmost part of the state as the low moves out.  Monday and Tuesday will have highs in the 50s and lows in the mid 30s. Wednesday will be warmer with highs in the 60s and lows in the upper 30s and 40s. There's a chance of rain moving in from the west.

Precipitation totals will be 1 to 1.5 inches of rain.  The 8-14 day outlook is showing temperatures below normal for the northern corner of the state, but normal for the rest of the state and precipitation above normal.  Currently western NY and northwest NY are abnormally dry.  Parts of St. Lawrence and Jefferson counties are experiencing moderate drought.  Drought conditions are continued to be likely for western NY through July.

Soilborne Viruses in Winter Wheat

Gary C. Bergstrom
Plant Pathologist, Cornell University

return to top

Symptoms of soil borne viruses are now visible on susceptible winter wheat cultivars.  Winter wheat cultivars were rated for symptoms of soilborne viruses on May 6 in dedicated virus nurseries in Trumansburg (for Soilborne wheat mosaic virus, SBWMV) and Ithaca (for Wheat spindle streak mosaic virus, WSSMV).  WSSMV is widely distributed in NYS.  SBWMV has been confirmed only in certain areas in southern portions of the Finger Lakes Region, but this is a good time to check if it is also present in your locale. Figure 1, depicts the typical leaf symptoms of SBWMV.

Figure 1: Symptoms of SBWMV

Susceptible indicator cultivars of wheatinclude Ashley, Jensen, Pioneer 25W36, FS 430W, FS 300, SW 50, and SW 80. In Figure 2, symptomatic plants on the right were from the infestednursery in Trumansburg, whereas healthy plants on the left were from an un-infestedplot less than 100 feet away.

Figure 1: Visual Symptoms of Soilborne Wheat Mosaic Virus

For more information on soilborne viruses in New York, referto What's Cropping Up? Vol 19, No. 3, May-June 2009, Pages 1-2.

Fungicide Options for Wheat

Gary C. Bergstrom
Plant Pathologist, Cornell University

return to top

Foliar fungicides can be useful tools in the integrated management of powdery mildew, fungal leaf blotches, leaf rust, and Fusarium head blight (with associated vomitoxin) in New York.  There are ten fungicide products currently labeled for use in New York and they represent different chemical groups based on fungicidal mode of action, i.e., strobilurins, triazoles, and combination products.  Strobilurin products are Quadris 2.08 SC and Headline 2.09 EC.  Triazole products are Caramba 0.75 SL, PropiMax 3.6 EC, Proline 480 SC, Prosaro 421 SC, Tebuzol 3.6 F, and Tilt 3.6 EC.  Combination products are Quilt 200 SC and TwinLine 1.75 EC.

Applications prior to flag leaf appearance:
All of the labeled products mentioned above provide satisfactory control of powdery mildew and leaf blotches, the diseases most commonly observed during jointing to flag leaf emergence stages.  Materials can be selected based on differences in relative efficacy but also on price and availability.

Applications from flag leaf appearance to head emergence:
Stobilurin and combination products are not recommended at this stage as late stage applications of strobilurins have been associated with increased levels of vomitoxin (deoxynivalenol) in wheat grain.  The triazole products should be considered for foliar disease control at this time.

Applications at beginning of flowering (anther emergence):
This is the critical window for suppression of Fusarium head blight. The most efficacious products for suppression of Fusarium head blight and deoxynivalenol toxin accumulation are the triazole products Caramba, Proline, and Prosaro, each registered recently in New York.  The alternative triazole products PropiMax, Tebuzol, and Tilt  are less efficacious against Fusarium head blight and toxin, but their cost is also less.  All of the registered triazole products should provide acceptable levels of control against leaf rust, leaf blotches, and powdery mildew on the flag leaf.  No fungicides should be applied after 50% anther emergence.

Additional information on disease control can be found on product labels. Please follow label directions carefully when applying fungicides.

Beware of using the same insecticide seed treatments on all your corn fields!

Ken Wise

return to top

Much of the corn seed you plant now is pretreated with an insecticide. Crusier Extreme 250 and 1250 and Poncho 250 and 1250 are the treatments widely used on field corn. The active ingredient in Crusier is thiamethoxam and clothianidin with Poncho. While they are different active ingredients, thiamethoxam and clothianidin are in the same chemical family of nicotinoids. These are broad-spectrum, systemic insecticides.  The 250 rate is for early season insect pests like cutworms, wireworms, seed corn maggots, white grubs, chinch bugs, and flea beetles. The higher rate if for controlling moderate to moderately high populations of corn rootworm.

Remember the word "RESISTANCE!" Many insect species have developed resistance to insecticides. Corn rootworm could and most likely will develop resistance to these seed treatments if we do not watch out. There are 2principles at work in this resistance. These seed treatments are in the same chemical family of nicotinoids. This means the insecticide kills corn rootworm at the same receptor (the same way) in every insect. The second is when an insect is over exposed to the same family of insecticides over and over across all corn acres they develop resistance. This means corn rootworm larvae are constantly being exposed to the low and higher rate of the insecticide from year to year.  Under these conditions there is the potential that a few corn rootworms exposed to the insecticide may survive. If so, these insects carry the gene for resistance. A portion of their offspring will have resistance to the insecticide. Over time you will develop a population of corn rootworm beetles that are resistant to the seed treatment.


It is important to mix your pest control strategies for corn rootworm.

Use shorter corn rotation to 2 to 3 years. 

Use the older method of T-banding Force on some of your corn acres where corn rootworm is over threshold

Use Bt. Corn for corn rootworm on some of your corn acres where corn rootworm is over threshold.

Use other (non- nicotinoid) seed treatments (not pre-treated) on some fields for early season corn insect pests like seed corn maggot. If corn rootworm is problem in these fields make sure you have alternative control in place for this insect pest.

Lady Beetle of the Week. Fourteen Spotted Lady Beetle

Ken Wise

return to top

Lady beetles play an important role in our agro-ecological systems. They are predators of aphids and other small insect pest. One lady beetle found in alfalfa fields this week was the Fourteen Spotted Lady Beetle (Propylaea quatuordecimpunctata). This lady beetle was accidentally introduced to North America from Europe. Some people think it was transferred on a ship in the St. Lawrence Seaway sometime in the late 1960s. This lady beetle does feed on aphids and can consume up to 1000 aphids/each in a lifetime. This is a small beetle that is only 4 to 5 millimeters. In the late 1980s into the early1990s the US tried to establish populations of these lady beetles in the Western US. To date they have not found an established population in the west. They can be found in fields, gardens and trees in NY feeding on aphids and other small insects.

Alfalfa Weevil Scouting/ Management and Growing Degree Days

Ken Wise

return to top

Alfalfa weevil can be a problem for established alfalfa fields prior to and shortly after first harvest.  To avoid unnecessary losses associated within jury from this insect pest begin monitoring fields in mid to late April when growing degree days have reached about 280 GDD (base 48F). The monitoring process is very straight forward. Look for signs of weevil feeding as holes in leaves and leaf buds and assessing the percentage of leaves affected. Here's how:

  • Pick 50 alfalfa stems at random throughout the field.
  • Look for the small "shot holes" in the leaves that indicate that larvae are feeding.

Record the percentage of alfalfa stems that show the "shot hole" feeding damage in the top 3 inches of the canopy.

Beforethe first cutting, if 40% of the stem tips show feeding damage, you are at the "action threshold". It's time to do something!

The good thing is that alfalfa weevil can generally be controlled by harvesting. If you reach an action threshold within a week of your normal 1st cutting date, early harvesting will help avoid economic, yield, and forage quality losses. Alfalfa weevils only have one generation per year and are typically not a problem after first harvest. Occasionally, weevil can damage alfalfa re-growth after harvest. This damage may be more evident in the windrow areas, and can be more noticeable under cool or droughty weather conditions. If you find that 50percent of the new growth is damaged, with many small larvae present, a chemical control may be warranted.

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)

CURRENT Accumulated Growing degree days (48F Base)

March 1 -   May 5, 2010

Base 48 F
Base 50 F
*Indicates missing data
source: NEWA

Clipboard Checklist

Keith Waldron

return to top


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

*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, purple deadnettle, field penny cress, shepherd's purse; annuals: giant ragweed, lambsquarters, Pennsylvania smartweed, common sunflower

Alfalfa and Grass Hay:

*Monitor alfalfa for alfalfa snout beetle (In Oswego, Jefferson, Cayuga, Wayne, Lewis, St. Lawrence, Clinton, Essex, and Franklin counties)

*Monitor alfalfa for crop condition, alfalfa weevil, foliar, systemic and crown rot diseases.

*Evaluate established legume stands for winter damage (thinning stand, frost heave, Brown Root Rot), determine average alfalfa stand count, adjust crop plans if necessary

*Monitor alfalfa seedings for weeds, insects &diseases.

*Timothy stands: check fields for symptoms of cereal rust mite

Small Grains:

*Assess crop for adequate stand and plant vigor

*Monitor winter grain fields for over wintering survival, crop growth stage, virus and other foliar disease symptoms, weed pressure, insects (cereal Leaf beetle) goose damage

*Checkwinter wheat for signs of foliar diseases, potential need for fungicideapplication.

Field Corn:

*Pre-plant weed evaluation

*Finish corn planting by May 15, if soil conditions allow

*Using a Bt hybrid? Have a refuge plan?

*Post emergence: Determine corn plant populations, make notes on germination problems, monitor for weeds, note presence of "who", "how many" and "where"

* Early season corn pests: seedling blights, seed corn maggot, white grub, wireworm, black cutworm

*Adjust post emergence weed control actions


*Pre-plant field assessment and weed evaluation


*Check and mend fences as needed.

*Check crop growth

* Check for presence of undesirable or plant species harmful to livestock.

*Review/Plan rotation system


*Arrange for custom weed control or check your own application or cultivator equipment for readiness or need for repairs.

*Check nozzles, pumps, etc. ,recalibrate pesticide application equipment regularly before use.

*Check/tune up soybean planting equipment

*Calibrate planting equipment- maintain records on crop planting rate per field

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


*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

Cattle on Pasture:

*Monitor animals for horn fly, face fly and other pest management needs including presence of poisonous plants.


 Emergency responder information on pesticide spills and accidents?

      CHEMTREC - 800-424-9300

For pesticide information?

      National PesticideInformation 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.

Mark Your Calendars

return to top

June 3 -- Small Grains Management Field Day, Musgrave Research Farm, 1256 Poplar Ridge Rd., Aurora, NY 
Free registration at 9:00am.  Program runs from 10:00am-12:00noon. Dec and CCA credits have been applied for
For more information contact Larissa Smith at 607-255-2177 or

July 14-- Weed Science Field Day, Thompson Research Farm, Freeville, NY (morning program)

July 14-- NYSABA Summer BBQ, Musgrave Research Farm, 1256 Poplar Ridge Rd.,  Aurora, NY (12:00 noon)

July 14-- Weed Science Field Day, Musgrave Research Farm, 1256 Poplar Ridge Rd., Aurora, NY (1:30pm 5:00pm)

July 22-- Aurora Farm Field Day, Musgrave Research Farm, 1256 Poplar Ridge Rd., Aurora, NY (10:00am-3:00pm)

Contact Information

Keith Waldron

return to top

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