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Weekly Field Crops Pest Report 2012

September 10, 2012, Volume 11 Number 21

  1. View from the Field
  2. Weather Outlook
  3. Planting Wheat? Hessian Fly-Safe Date is Not Only about Hessian Fly
  4. Corn Ear Rots
  5. Western Bean Cutworm
  6. Clipboard Checklist
  7. Contact Information

View from the Field


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This is the week of the corn and soybean plant diseases. There have been many reports of plant diseases including, sudden death syndrome, white mold, soybean vein necrosis virus, downy mildew, septoria leaf sport in soybeans. In corn we have had reports of gray leaf spot, northern corn leaf blight, eye spot, corn rust and common smut.

Gray Leaf Spot
Gary Bergstrom (Cornell Field Crops Plant Pathologist) gave a workshop on corn and soybean diseases in Columbia County on September 7. He pointed out that gray leaf spot is a disease that is starting to show up more often around the state. The farm that hosted the workshop had issues with gray leaf spot. Much of the Hudson Valley has seen an increase in the incidence of Gray Leaf Spot. The Cornell Research Farm has in Valatie (Columbia County) has had this disease the last few 3 years. Cercospora zeae-maydis is the fungus that causes the disease. Early symptoms are yellow to tan lesions with a faint watery halo. As the lesion progresses it turns brown and rectangular in shape that exist between the distances of the veins. When fully developed the lesion can be 3 to 4 inches long and a 1/6 to 1/8 inch wide. The fungus can overwinter on corn debris left on the soil surface. Spores develop when it starts getting warm and the humidity started to rise in late spring. The spores can be transmitted by both wind and rain. In some cases gray leaf spot can limit yield up to 5 to 40 bushels of corn per acre.

Management of Gray Leaf Spot

  1. Select corn hybrid with at least moderated resistance to gray leaf spot.
  2. Crop ration and tillage is an effective method to control the fungus.
  3. If you maintain no tillage or reduced tillage rotation away from corn 2 years can help control the fungus.
  4. If the corn has gray leaf spot use of a fungicide is available to the fungus.

Soybean Aphids
While soybean aphid populations have been low statewide I was in a field in Dutchess county this week where the average was 225 aphids per plant. This is more than double from the previous week. There were also a lot of lady beetles adults and larvae in the field indicating the potential for a fair amount of biological control of the aphids. It should be noted that plants in this field were at the R6 stage and mature enough to not be at risk of yield damage by soybean aphids.

Other insect pests reported on corn this week were European corn borer and western bean cutworm larvae in ears. On soybeans I (Ken Wise) saw a lot of green stink bugs and nymphs. I have not seen Brown Marmorated Stink Bug in soybeans yet this season.

Weather Outlook

September 6, 2012
Jessica Rennells, Northeast Region Climate Center, Cornell University

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Last week temperatures ranged from 3 to 6 degrees above normal for most of the state. Rainfall amounts ranged from a trace to an inch for most of the state, areas in the Adirondack region had over an inch. The Base 50 growing degree-days ranged from 100 to 150, lower in the part of the Adirondack region.

Today temperatures will be warm in the mid to upper 80s with scattered showers and thunderstorms likely ahead of a cold front, some may be severe (strong winds, hail). Lows will be in the mid 50s to lower 60s. Friday temperatures will be cooler, ranging from the upper 70s to the upper 80s, scattered showers and thunderstorms will move out over eastern NY. Overnight temperatures will be in the mid 50s to low 60s. Heavy rain Saturday & Sunday. Saturday will be in the mid to upper 70s with scatted showers and thunderstorms from a stronger storm system and cold front, possibility for some to be severe. Lows will be in the 50s and low 60s, some 40s are possible.

Sunday will again have scattered showers and thunderstorms, highs will be in the 70s. Overnight temperatures will be in the mid to upper 50s. Monday will be in the low to mid 70s with some scattered showers. Overnight temperatures will be in the upper 40s to mid 50s. Tuesdays temperatures will be in the low to mid 70s. Lows will be in the upper 40s to mid 50s. Wednesday temperatures will in the low to mid 70s. Lows will be in the upper 40s to mid 50s.

The five-day precipitation amounts will range from inch to 2 inches, the higher amounts are expected in western NY. The 8-14 day (Sept 13-19) outlook is showing above normal temperatures and normal precipitation for most of the state, below normal precip for the southern edge of the state and the Catskills, southern Hudson Valley.

National Weather Service Climate Prediction Service Maps of 8-14 day outlooks

National Weather Service Eastern Region Headquarters watch/warnings map

NRCC Drought Page which features the US Drought Monitor map (updated every Thursday)

Planting Wheat? Hessian Fly-Safe Date is Not Only about Hessian Fly

Ken Wise
NYS IPM

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Several questions have come in this week regarding the recommended timing for planting wheat. For years, the standard recommendation for profitable wheat production has been to plant wheat after the Hessian fly-free date. This recommendation is based on the fact that at the dates indicated on the map below, Hessian fly adults would no longer be alive.  

Hessian fly, Mayetiola destructor, is a species of fly that is a significant pest of cereal crops including wheat, barley and rye. Hessian flies emerge in late summer, mate, and then oviposit in different types of grasses among them wheat.   Adult life span is extremely short, perhaps only a week, during which time they do not even feed.  After this short time span, adults die off.  

The larvae of this small insect feed between the stem and leaf sheath near the base of the plant in newly established wheat in the fall and again in the spring. Damage during the fall causes stunting of the new plants; the spring and early summer damage results in unfilled heads and fallen straw. Look for the small white maggots and brown puparia (the resting stage, commonly called "flaxseeds" for their resemblance to the flat spindle- shaped seeds of flax) deep within the sheaths of the lower leaves in the weeks just before wheat harvest.

The fly-free date is set at a time when it is expected that the adults have died and are no longer around the area.  As a result, damage caused by this insect will likely much less if wheat if planted after the specific date fly-free date in your area. Note the dates shown on the map are adjusted for altitude i.e. higher elevations = earlier Hessian fly free dates. The recommendation is to plant wheat only after the fly-free date for your area but as soon after that date as possible. Ask your seed dealer about the availability of Hessian fly-resistant varieties.

Use of the recommended Hessian fly-free date guidelines has kept damage to wheat from this pest to a minimum in NY. However, the Hessian fly-safe date is not only about the Hessian fly. Another excellent reason to plant wheat after the fly-safe date is to minimize problems with diseases, especially aphid transmitted diseases such as barley yellow dwarf virus (BYDV).

BYDV is transmitted by aphids and tends to be most severe when transmission occurs in the fall. Research has shown that aphid populations tend to crash after the fly safe date due to unfavorable weather conditions (think first frost), leading to fewer problems with BYDV. Planting date studies conducted at OSU have shown that BYDV problems and yield loss associated with this disease are much higher when wheat is planted well before the fly-safe date. Planting after the fly-safe date also minimizes early establishment of other diseases such as Stagonospora blotch and leaf rust.

hessian fly chart
see Insects of Small Grains, Hessian Fly

No insecticides are recommended for control of the Hessian fly. Plow under stubble of infested grain at least 6 inches immediately after harvest. Destroy all volunteer wheat by disking when the plants are small.

(Portions of this article were adapted from an Ohio State C.O.R.N. article by Pierce Paul and Ron Hammond.)

Corn Ear Rots

Ken Wise
NYS IPM

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While scouting fields this week I can across some corn ear rots in the field. These can be an important issue if you are feeding this to dairy cattle or other animals, since some fungi 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 presence of ear rot 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 Residues

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 prior to adding new grain to 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, 1-800-496-3344

The Cornell College of Veterinary Medicine's Animal Health Diagnostic Center, (607) 253-3900

Western Bean Cutworm

 

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Our Western Bean Cutworm monitoring program is winding down. Twenty-three traps were operating this week. Field corn is maturing and some fields have been harvested.
WBC larvae have been found in corn in some locations in Wyoming, Jefferson and Lewis counties. Unlike other corn ear infesting larvae, such as European corn borer, multiple WBC larvae can infest one corn ear. The best way to identify them is by the two wide dark bands located on the pronotum (shield) behind the head. These bands become more distinct as the larvae reach full size. Larvae have no stripes or distinguishing spots or warts (see photo). Larvae complete development in 43-70 days, depending on temperature. Mature larvae will drop from the plant and overwinter in cells that they construct 5-10 inches below the soil surface. Light, sandy soils are most conducive for successful overwintering. Those larvae that successfully overwinter will pupate and emerge as moths next June. See: Western Bean Cutworm identification card including larval stages.

western bean cutworm on corn
Photo by Joe Lawrence, CCE Lewis County
Accumulated western bean cutworm moths captured per location as of 9.7.12

County Location Total WBC County Location Total WBC

Broome

Whitney Point

0

Livingston

Cuylerville

9

Cattaraugus

Olean

16

Livingston

Lima

57

Cayuga

Auburn

59

Madison

Kirkville

34

Cayuga

Aurora

29

Monroe

Churchville

35

Cayuga

King Ferry

1

Monroe

Hamlin

54

Cayuga

Sherwood

0

Monroe

Spencerport

38

Chautauqua

Kennedy

148

Niagara

Lockport

27

Chenango

Afton

14

Oneida

Clinton

23

Chenango

Sherburne

19

Oneida

Clinton

21

Clinton

Beekmantown

50

Onondaga

Baldwinsville

31

Clinton

Chazy

24

Onondaga

Tully

16

Cortland

Marathon

2

Ontario

Farmington

2

Cortland

Preble

81

Ontario

Geneva

47

Delaware

Oneonta

19

Ontario

Hopewell

8

Delaware

Walton

34

Ontario

Stanley

29

Dutchess

Millbrook

40

Orleans

Waterport

21

Erie

Eden Z

148

Otsego

Garrattsville

13

Essex

Westport

19

Schoharie

Middleburg

22

Essex

Willsboro

13

Schuyler

Burdett

1

Franklin

Malone

140

Schuyler

Valois

9

Genesee

Alexander

17

St.Lawrence

Madrid

301

Genesee

Batavia

23

Steuben

Avoca

20

Genesee

Batavia

38

Steuben

Wayland

34

Genesee

Leroy

41

Suffolk

Riverhead

1

Genesee

Stafford

16

Tioga

Owego

1

Genesee

Stafford

91

Tioga

Owego

20

Green

 

27

Tompkins

Varna

27

Herkimer

Little Falls

47

Washington

 

7

Jefferson

Ellisburg

193

Wayne

Macedon

13

Jefferson

Plessis

42

Wayne

Williamson

24

Jefferson

Sacketts Harbor

344

Wyoming

Attica

276

Lewis

Martinsburg

323

Wyoming

Pike

0

Livingston

Avon

48

Yates

Bellona

26

Livingston

Caledonia

28

Yates

PennYan

32

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

Corn:
* Monitor fields for plant vigor, growth stage, late season pest issues (European corn borer, foliar diseases, nutritional deficiencies, vertebrate damage)
* Monitor for weeds, note presence of "who", "how many" and "where"
* Monitor reproductive stage corn fields for foliar diseases, stalk standability issues, corn ear damage (insect pests and diseases)
* Prepare storage areas to accept upcoming silage 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, bean leaf beetles and weed escapes

Dairy Livestock Barn Fly Management:
* Sanitation, sanitation, sanitation - clean animal resting areas, feed throughs, 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 temperature, moisture, pest status of bin stored small grains * 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 (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.

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