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Weekly Field Crops Pest Report 2008

August 21, 2008                 Volume 7 Number 18

1. View from the Field

2. Weather Outlook

3. Stop! Check for Corn Ear Rot

4. Think Weeds in the Fall!

5. Keeping Pest Records

6. Winter Wheat, Aphids and Yellow Dwarf Virus

7. Storing Corn or Soybeans? Remember Stored Grains Pests!

8. Soybean Rust Update

9. Soybean Aphid Update

10. Clipboard Checklist

11. Contact Information

View from the Field

Ken Wise
NYS IPM

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Patricia Westenbroek (Sullivan County) reports a lot of deer damage in field corn. Mike Stanyard (WNY Dairy/Field Crop team) reports issues with new seedings. One field had an excessive amount curly dock. Once dock is established in a new seeding it is very difficult to control. Mike is also finding soybean fields with white mold. Some producers in western NYS have had to apply fungicides to attempt to control the white mold. Sharon Bachman (Erie County) reports black bird damage in field corn. Bird damage may predispose ears to infection by various molds including some that could present problems to animals/humans (vomitoxins). More information on birds in corn can be found at eXtension Blackbirds. Brain Aldrich (Cayuga County) reports insect infestations in wheat storage grain bins. ALWAYS remember to clean the whole grain bin before adding new grain. For more on IPM for stored grain see article below.

News from Larissa Smith on a new web-format for “What's Cropping Up” The electronic version of the most current issue can be found at What's Cropping Up.

Individual articles in word or pdf form from 2000 to 2008 can be accessed from the above page by clicking on WCU Archives or at What's Cropping Up archive.

Weather Outlook

Art DeGaetano
NOAA Northeast Regional Climate Center, Cornell University

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Weather Update 8.21.08

High pressure dominated most of the past week bring generally dry and slightly cooler than normal weather.  Temperatures averaged 2-3 degrees below normal during the week across the state.  A few places dipped into the upper 30s on Wednesday morning. Most of the state accumulated between 100 and 160 base 50 degree days.  Seasonal degree day totals are now near 2600 close to New York City, around 2000 in the Albany area, between 1800 and 1600 across the Southern Tier and between 1400 and 1500 in the North Country.  These accumulations are close to last years and the 30-year normal.

Precipitation was generally less than 1 inch across the state, with some pockets of 1-2 inches particularly in the North Country, near Buffalo and on western Long Island

High pressure should again dominate the weather pattern over the next week.  Temperatures through Sunday will average above normal, with highs in the 80 and lows in the 60s across most of the state.  Sunday will be the warmest day with the temperature reaching into the high 80s even in upstate locations.  Late Sunday and Monday will be the next chance of rain as a front moves through quickly from the west.  Precipitation totals should remain below a half inch.  This front will cool temperatures off to more normal levels through Wednesday (highs in the upper 70s to near 80 and lows in the mid-50s to low 60s).  Around this time we will have to keep an eye on the moisture from Tropical Storm Fay, which may finally start to work its way north.  The southeast U.S. should see some very high rainfall totals as this storm stalls over the region through early next week.

Beyond next Wednesday, a high pressure is expected to continue in the Northeast, bringing slightly warmer than normal temperatures, but allowing ample chances for showers across the region.

Stop! Check for Corn Ear Rot

Ken Wise
NYS IPM

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Are you ready with the chopper or combine? STOP; check for corn ear rots first! Some kinds of fungi can create mycotoxins that are toxic to livestock. Taking a few minutes to check a field for certain ear rots can help you determine if you want to feed your field of corn to livestock. Pull back the husks on several plants and look for the presence mold growing on the ear of corn. The following are specific symptoms of certain ear rot diseases that can be found in NYS:

Fusarium Ear Rot appears as a white-to-pink or salmon-colored mold. This mold can begin with bird, deer or insect-damaged kernels. Fusarium ear rot may contain fumonisins which are mycotoxins that can be toxic to livestock.

Gibberella Ear Rot symptoms are pink to reddish colored mold. This disease starts near the tip of the ear and progresses down toward base of the ear. Gibberella can produce vomitoxin and zearalenone which is toxic to many kinds of livestock.

Diplodia Ear Rot symptoms appear as a thick white mold that usually starts near the base of the ear. This disease can also appear on the plant as raised black fruiting bodies on moldy husks or kernels. Diplodia does not produce any known toxins.

Cladosporium Ear and Kernel Rot symptoms appear as greenish black, blotched or streaked kernels scattered over the ear. This disease can also infect kernels that have been damaged by insects, birds, deer, hail, or frost. The disease can progress after the grain is harvested and stored.

Penicillium ear rot or blue eye symptoms range from a powder-like green or blue-green mold that is on and between the kernels and normally on the tip of the ear. If this disease progresses in storage it is referred to as blue eye because the germ is a bluish-green color. Penicillium ear rot can produce a mycotoxin called “ochratoxin”.

If you discover certain ear rot diseases make notes of the hybrid, tillage methods, rotation history, and planting date. By doing this you can avoid the disease occurrence in the future. The following is the effectiveness of specific management practices for corn ear rots:

Corn Disease
Resistant Variety
Crop Rotation
Clean Plow
Down of Residue
Fungicides
Ear Rots
2
2
2
4
1= highly effective, 2= moderately effective, 3=slightly effective, 4= not effective, 5 = not usually economical,
Reference: Purdue University Field Crops Pest Management Manual

While there isn't any practical solution for coping with ear rots this late in the current season proper fertilization, timely weed control and reductions in insect pest pressure can help reduce risk of disease. For example: European corn borer (ECB) resistant Bt corn is at lower risk for injury by this insect. Lower risk means fewer ECB tunnels into stalks and less potential for fungi to infect through wounds and cause stalk rot. Also avoid continuous planting of corn under conservation tillage where stalk rot can be prevalent. If you are harvesting corn grain make sure you clean the grain bins. Keeping the proper temperature, moisture content and good aeration in the grain bin can reduce storage molds from developing. It is important to have regular inspections of the stored grain. This is essential to minimize risk of developing insect and mold associated storage problems. Harvest silage at recommended maturity and moisture level, and pack silage tightly and exclude air rapidly. Consider using organic acid preservatives if you can't exclude air or reduce moisture. If you had a lot of stalk rot and were growing for grain consider chopping earlier for silage to minimize lodging and combine losses. There are kits you can purchase to test your corn for different toxins on your own farm. The following are places where you can also test your corn:

Dairy One Forage Lab in Ithaca: For more information, call the lab at 1-800-496-3344 extension 172.

The Cornell College of Veterinary Medicine's Nutritional and Environmental Analytical Services Lab: More information is available on the web (www.vet.cornell.edu/public/neas/) or from lab manager Joe Hillebrandt at 607-257-2345

Think Weeds in the Fall!

Ken Wise
NYS IPM

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In the fall, weeds are fully-grown and easily identified. Correctly identifying and recording significant weed infestations and their location is helpful for improving weed management decisions. Knowing the weed type and biology (broadleaf, grass, sedge, summer or winter annual, biennial, or perennial) is critical in selecting the right weed control measures. Remember, while herbicides are widely used for weed control other methods like crop rotation, cultivation, proper fertilization, planting dates, banding pre-emergence herbicides, crop spacing, plant populations, cover crops and combinations of these techniques should also be considered as part of an integrated weed control program. Conduct your fall weed surveys from late August through October. Sketch out a map of the field, walk each 1/4 of the field, and record the identity and relative infestation of the significant populations of weeds you observe. While no economic thresholds have been developed for weeds in New York, we recommend using a weed rating scale. The following scale can help you determine the severity of weed infestations in cornfields.

Evaluating Weed Presence- Weed Rating Scale:
Determine the intensity of each weed species as follows:

None: No weeds present

Few: Weeds present but very few plants within the field. Enough plants to produce seed but not enough to cause significant economic loss in the current year.

Common: Plants dispersed throughout the field, an average of no more than 1 plant per 3 feet (.91m)
of row, or scattered spots of moderate infestation.

Abundant: Fairly uniform concentrations across field. Average concentrations of no more than 1 plant per foot (.30m) of row or scattered spots of severe infestations.

Extreme: More than 1 plant per foot (.30m) of row for broadleaf weeds and 3 plants per foot of row for grasses, or large areas of severe infestations.

So take a few minutes and encourage growers to look at their fields---it will help save on weed control costs and increase crop production. Remember, if you don't look, you will never know what weeds are there.

Keeping Pest Records

Ken Wise
NYS IPM

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It is very important to keep records from year to year on certain pest problems that may have occurred. Write down observations that you made over the season. Did potato leafhoppers go over threshold and which field(s)? Were there certain corn diseases present? Did you have corn that had corn rootworm injury? Were there new weeds or weed escapes you did not expect this year? Pick up a pencil and write them down on a field to field basis to better select certain management practices the next season. For example, if you were hit with potato leafhoppers this season and you want to rotate your alfalfa, one management option to consider for the future is use of a potato leafhopper resistant alfalfa variety. Another example might be to select wheat varieties that are resistant to certain diseases. If you had weed escapes you might reconsider your selection of weed control products. Are your pesticide use records up to date? Rates, dates, efficacy, etc. It is always important to keep pesticide records up to date.  If you wait too long you may forget what happened in certain fields. So write them down! A sharp pencil beats a dull memory…

Winter Wheat, Aphids and Yellow Dwarf Virus

Ken Wise
NYS IPM

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Barley yellow dwarf virus, also know as yellow dwarf virus (YDV) in wheat is a serous disease across the country. This disease is transmitted by several species of aphids that infest wheat. When infected aphids feed on the plants they infect the wheat with the virus. Winter wheat that is infected in the fall does not show symptoms. Symptoms start to appear mid-spring as yellowing of leaves. One management strategy is to plant wheat after the Hessian fly free date in your region. This can limit the number of aphids entering the fall seeded winter wheat fields. Another management option is to plant a wheat variety that is resistant to YDV.

Storing Corn or Soybeans? Remember Stored Grains Pests!

Ken Wise
NYS IPM

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Have plans to store your soybean and grain corn harvest on farm? If so, now is the time to start CLEANING your storage bins. Sanitation is the key to keeping insect pests out of your stored grains. Soybean and Corn harvest is not as far off as you may think so knowing what you need to do is important. 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. Remove all weeds, spilled grain and debris 6 to 10 feet from around the grain bin. This will remove all habitats that can support a grain bin pest problem.

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.

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

(See: IPM in Kentucky Farm Stored Grain and Improve Stored Grain Through IPM from Oklahoma State)

Soybean Rust Update

Gary Bergstrom
Plant Pathology, Cornell University

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Sentinel plots in New York State have been established in the following counties: Cayuga, Chautauqua, Chemung, Columbia, Cortland, Jefferson, Lewis, Madison, Niagara, Oneida, Ontario, Schoharie, Seneca, Steuben, Wayne and Yates. Plant growth stages in these plots range from V-5 to R-5. Low levels of downy mildew and frogeye leaf spot were detected in single sentinel plots this past week. Mid to high levels of Septoria brown spot were detected in 40% of the sentinel plots across NYS this past week.

No new detections have been reported in the U.S. in the past week.

Since the beginning of 2008, soybean rust has been reported on kudzu in two counties in Alabama; one county in Georgia, sixteen counties in Florida (two of these counties had reports on coral bean and snap bean and one had a report on soybean); three counties in Louisiana; one county in Mississippi, and four 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. (Updated August 12, 2008)

NY State Soybean Rust Hotline: 607-255-7850

NYS Soybean Rust Website

USDA Soybean Rust Website

Soybean Aphid Update

Keith Waldron
NYS IPM

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Soybean aphid (SBA) populations remained low again this week across areas reporting in NY. Fields monitored are generally averaging 0 to less than 5 SBA's per plant at this time. While individual plants may have higher numbers, all fields reporting were well below threshold. Natural enemy populations, such as lady bird beetles, are present and increasing in many areas. Field monitoring continues to be hampered by frequent storms and wet conditions.

Crop Growth Stage - V-12 to R-4

Soybeans are in reproductive growth stages in most areas reporting. Soybean heights vary from 16 inches to 30 plus inches tall.

Soybean aphid scouting and management – the low numbers of aphids being reported across NY continue to support close inspection of fields as a source of objective information on which to base potential insecticide use decisions. Potential exists for deposition of soybean aphids carried on weather fronts from more western states. Growers are encouraged to monitor for presence of soybean aphids, other insects and diseases. Fields entering the blooming stages should be monitored closely for SBAs, foliar diseases and white mold.

As soybean fields enter their pod fill growth stages, growers should evaluate need for an insecticide based on a soybean aphid population assessment. The national soybean aphid management recommendations, including the recommended soybean aphid action threshold for R1 (beginning bloom) to R5 (beginning seed) reproductive stage soybeans are:

R1 to R5 growth stages

- During the period when the soybean crop is reproductive (i.e. flowering) in the R1 to R5 growth stages, an insecticide application may be necessary when 250 or more aphids occur per plant and approximately 80% of the field is infested and populations are increasing. Sequential scouting in the same field is necessary in order to determine if populations are increasing. Comparing SBA counts over a week or more is necessary.

(For more information see: Management Toolbox - Guidelines - USA , http://sba.ipmpipe.org/)

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, yields, etc.

* Watch for weed escapes, any patches of herbicide resistant weeds?

Field Corn:

* Note crop growth stage and condition

* Check for European corn borer, armyworm, foliar diseases, vertebrate injury (birds / deer), weed escapes, herbicide injury, nutritional deficiencies, etc.

* Check tasselling / pollinating corn for corn rootworm populations

* Monitor weed populations noting presence of "who", "how many" and "where"

* Check herbicide resistant corn fields for herbicide resistant soybean

Alfalfa & Hay:

* Monitor alfalfa seedings for weeds, for potato leafhopper & diseases.

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

* Storage areas cleaned and ready to accept next harvest?

Soybeans:

* Note crop growth stage and condition

* Evaluate stand for soybean aphid, spider mites, deer, weed assessment, foliar disease incidence

* Check herbicide resistant soybean fields for herbicide resistant corn

Dairy Cattle: Livestock Barn Fly Management:

* Monitor animals and facilities for house fly and stable fly populations

* Check facilities for favorable fly breeding conditions: (organic matter + moisture): leaks in watering systems, roof gutters for leaks and potential overspill, drainage,

* 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 * Continue fly monitoring: install "3X5" index card fly speck monitoring cards through out barn

* Use, replenish, replace fly management materials: sticky fly tapes/ribbons, insecticide baits, natural enemies (parasitoids), fly population monitoring (3 x 5) spot cards

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

Dairy Cattle: Pasture Fly Management:

* Monitor animals for presence of face flies, horn flies and stable flies. Action guidelines: face flies (average 10 per animal face), horn flies (average 50 / dairy, 200 / beef cattle per animal side), stable flies average 10 per animal  (all four legs)

* Check feed bunk / water source locations for signs of stable fly breeding (moist undisturbed organic matter – spilled feed, round bales, etc.), minimize source of moist organic matter i.e. fly breeding areas in barn and in adjacent animal loafing yard

* Check paddocks for forage quality / quantity, rotate as appropriate

* Check paddocks for vegetation poisonous to livestock

* Consider use of fly traps to help reduce deer, horse and stable fly populations

Storage:

* Pre-clean in and around grain storage bins in anticipation of soybean and grain corn harvests.

* Keep areas around storage bins and silos clean and mowed

Equipment:

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

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

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