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Weekly Field Crops Pest Report 2009

August 7, 2009                        Volume 8 Number 16

1. View from the Field

2. Weather Outlook August 6, 2009

3. What pest problems to consider when planting winter wheat

4. Corn Silks and Beetles

5. Soybean Rust Update

6. Soybean Aphid Update

7. Clipboard Checklist

8. Contact Information

View from the Field

Ken Wise
NYS IPM

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Soybean aphids continue to be problematic across New York. Many soybean fields have been over the economic threshold for soybean aphids. Many of these fields have been sprayed with an insecticide. Other soybean fields have seen a drop in aphid numbers over the past week the result of activity by a variety of natural enemies including aphid fungal diseases. See this weeks soybean aphid update for more information. In my soybean sentinel plot in Washington County we have discovered downy mildew and bacterial blight. Remember no bacterial diseases can be treated with a fungicide.

Potato leafhopper (PLH) populations remain low across the state. One exception was an over threshold field reported at the Cornell Research Farm in Valatie. There were 100 PLHs in 3 samples (one sample equals10 sweeps with the net) in 20 inch alfalfa.

Warmer weather and moist conditions have provided conditions favorable for increasing house and stable fly populations on dairy farms.

Weather Outlook August 6, 2009

Drew Montreu
NOAA Northeast Regional Climate Center

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Temperatures during the past week were pretty close to normal, with the entire state ending up within 3 degrees of average. Most areas were on the cool side of that though. Precipitation was widely variable, with none falling to the north of Buffalo, and over 4 inches falling over parts of the Catskills. In general, areas east of I-81 had the best shot for over 2 of rain, while areas west of there mostly got less than 2.

Base 50 Growing Degree Days accumulated 100 to 150 across most of the state, with the lower values in the higher elevations, as usual. Comparing seasonal values to last year, nearly everywhere is 1 to 2 calendar weeks behind, and the majority of the area is in the lower, 10 to 14 days behind range. Compared to normal, portions of Western New York and the Tug Hill are 7 to 10 or more calendar days behind, while a few areas in the Southern Tier and Hudson River Valley are a couple days ahead. For the most part though, areas are 3 to 7 days behind normal.

Another pretty decent week is upcoming, with high pressure keeping control of the weather through most of Saturday. That means plenty of sunshine for the next few days. Temperatures will be a bit cool, with highs today, tomorrow and Saturday in the mid 70s. Lows should be in the low to mid50s. There is a chance of an isolated shower or storm on Saturday, but most areas should be dry. The chances for a storm increase a bit on Sunday, but again, the majority of places will see little if any rain, with highs in the low to mid 80s and lows near 60. Some heat will come in on Monday after a warm front moves through in the morning, with morning lows in the upper 60s. Highs will reach into the upper 80s with some scattered thunderstorms along this front and in the afternoon. A cold front will come through on Tuesday, but not before highs reach into the mid to upper 80s once again. Tuesday will have the best chance of rain as that front goes through. There could be some showers on Wednesday as the front slowly moves to the east, and highs will be near 80, with lows near 60.  Over the next 5 days, most areas can expect to get between one-quarter and three-quarters of an inch of rain. The 8 to 14 day outlook is calling for slightly warmer than normal weather, accompanied by more dry weather.

What pest problems to consider when planting winter wheat

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Planting winter wheat is just around the corner. There are several factors to consider when planting winter wheat. The first is to never plant wheat in the same field two years in a row. By rotating you reduce the risk of several diseases like eyespot foot rot, powdery mildew, leaf rust, Stagonospora nodorum blotch, glume blotch and more. The second item to consider is what winter wheat variety to plant. Of course you will look at potential grain yield, grain test weight and straw quality. It is also important to consider resistance to diseases in the varieties you select. Diseases of particular concern are wheat spindle streak mosaic virus, soil borne mosaic virus, yellow dwarf virus (formally called barley yellow dwarf virus), powdery mildew, leaf & stem rust and/or other disease problems your farm has had in previous years. For a list of potential wheat varieties consult your Cornell Guide for Integrated Field Crop Management (available online at www.fieldcrops.org). Next, remember to plant AFTER the Hessian fly free date. By doing so, not only are you avoiding infestations of Hessian fly but also certain aphids that can transmit yellow dwarf virus. The following figure shows the Hessian Fly Free Dates in NYS:

The use of certified wheat seed should be considered. When seed is certified you can be confident of the quality and it is void of diseases and weed seed. Next is to remember to always use a fungicide seed treatment to protect the crop from certain seed and seedling related diseases. Another core consideration is having a sound fertility program. When a plant is healthy it can complete with weeds and may tolerate more insect pest pressure and still maintain good yield.

Corn Silks and Beetles

Ken Wise
NYS IPM

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Every year I see two kinds of beetles feeding on corn silks: corn rootworm beetles and Japanese beetles.  I have been asked many times Does this feeding by beetles reduce pollination of corn Generally, these beetles do not affect pollination of corn. Corn rootworm beetles prefer to eat pollen. The corn plant can produce enough pollen to pollinate the ear of corn and still have plenty left over for the corn rootworm beetles.

In New York, the feeding of the adult beetles on silks can occasionally be a problem. Clipping of the silks can prevent pollination, resulting in poorly filled ears. If 10 or more adults are found per plant at silking, less than 50 percent of corn silks are brown, and silks <0.5 inch long, treatments to control adults may be warranted, and pollination has not yet occurred, apply an insecticide (see: www.fieldcrops.org, Table 3.6.1).

The good thing is that even a damaged silk can still receive pollen and willfertilize the ear. Reduced fertilization can only occur when the silk isclipped to less than a  inch long before pollination.

Japanese beetles also like to feed on the silks of corn. I have seen up to 8or 9 on one ear of corn. The thing with Japanese beetles is that they prefer tofeed on browning silks. When the silk has turned brown the ear of corn has alreadybeen pollinated. Japanese beetles also clump in certain areas of the field.Many times this is along edges and not the rest of the field.

Japanese Beetles on Feeding on Silks

Soybean Rust Update

Gary Bergstrom
Plant Pathology, Cornell University

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Scouting has begun in sentinel plots in NYS in Cayuga, Jefferson, Seneca, Washington and Wayne counties. This week low levels of bacterial blight, bacterial pustule and Septoria brown spot were detected in samples submitted from the NYS sentinel network. Nationally, on August 4th, soybean rust was reported on soybean in a sentinel plot in Baldwin County, Alabama. Additionally, recent detections of soybean rust have been made on kudzu in Alabama and Florida. Risk of spore transport to our region is low at this time. In 2009, soybean rust has been reported in the U.S. in 34 counties in five states (Alabama, Florida, Georgia, Louisiana and Texas). Updated August 7, 2009

See: New York State Soybean Rust Information Center

Soybean Aphid Update

Keith Waldron
NYS IPM

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NY SBA Commentary 8.6.09 (For the IPMPIPE website)

See USDA Public PIPE Website.

Crop Growth Stage Last Modified: 08/06/09

Soybean growth variable across state. Majority of fields currently reporting late vegetative growth stages to early pod fill R3.

Observation and Outlook - Insect Last Modified: 08/06/09

Soybean aphid populations building with fields reaching threshold being reported across NY. High populations reported in northern, eastern and western regions. Populations of beneficial arthropods including Coccinelids, syrphid flies, lacewings, parasitic wasps and fungal pathogens have been increasing statewide. Some fields in central NY that reported over threshold SBA numbers last week have experienced a precipitous drop in SBA numbers to low 20's this week resulting from impact of natural enemies including fungal disease of SBA's.

Infested soybeans populated mostly by non-winged SBA's with some winged forms present. Some fields with plants exhibiting stunting and crinkling/puckering of leaves. Some fields treated with insecticide earlier this season have again reached threshold for SBA, in some cases only 2 - 3 weeks post treatment. Fields receiving application of foliar insecticides will continue to require monitoring for possible soybean aphid re-infestation later this season.

Observation and Outlook - Disease Last Modified: N/A

Scouting and Management - Insect Last Modified: 08/06/09

SBA infestations variable on farms. Monitoring individual fields recommended to provide the best information for management decisions. Producers are encouraged to monitor soybean fields for this insect pest, natural enemies and mid to late season soybean diseases. Follow management guidelines as recommended in USDA protocols and Cornell Recommendations for Soybean Integrated Field Crop Management.

For more information see the USDA Public PIPE Website.

Clipboard Checklist

Keith Waldron
NYS IPM

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General:
* 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 any patches of herbicide resistant weeds, weed escapes
* Storage areas cleaned and ready to accept hay, wheat harvest

Corn:
* Monitor fields for plant vigor, growth stage, mid to late season pest issues (European corn borer, armyworm, foliar diseases, nutritional deficiencies)
* Monitor for weeds, note presence of "who", "how many" and "where"
* Monitor reproductive stage corn fields for corn rootworm beetles populations.

Small Grains:
* Evaluate crop for plant vigor, lodging, maturity / time till harvest
* Grain bins ready to accept upcoming harvest

Alfalfa & Hay:
* Monitor alfalfa seedings for weeds, insects & diseases.
* Check regrowth of established alfalfa stands for potato leafhopper, weed and disease problems.
* Storage areas cleaned and ready to accept incoming harvest

Soybeans:
* Evaluate stand growth, development and condition
* Monitor fields for soybean aphid, foliar diseases, white mold, natural enemies, defoliating insects, spider mites and weed escapes

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 overspill
* Continue fly monitoring: install "3X5" index card fly speck monitoring cards through out barn
* Install/refresh/replenish as needed: fly tapes, insecticide baits, natural enemies (parasitoids)

Dairy Livestock Pasture Fly Management:
* Monitor animals for presence of pasture fly pests. Treatment guidelines: Horn flies (50 per dairy animal side, 100 per side for beef cattle), face flies(10 per animal face), stable flies (10 per 4 legs). See IPM's Livestock page.

* Consider installing biting fly traps to reduce horse, deer and stable fly populations.

Storage:* Check storage areas (bunk silos, etc.) for readiness to accept upcoming wheat harvest
* Clean in and outside of storage bins and grain handling equipment
* Keep areas around storage bins and silos clean and mowed
* Check areas around storage bins and silos for vertebrate tunneling
* Check temperature of recently baled hay in hay mow

Equipment:
* Note any repairs needed for recently used equipment: tractors, tillage implements, planters, sprayers, etc. as they are cleaned and serviced.
* Service hay harvesting equipment as needed.
* Calibrate manure spreaders - maintain records on amount spread per field

PESTICIDE EMERGENCY NUMBERS
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 (inNYS)_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 CornellUniversity,607-255-1866, may be able to assist you in obtaining such information.

Contact Information

 

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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