July 31, 2014

NYS IPM Weekly Field Crops Pest Report, July 31, 2104

Volume 13 Number 13

 View from the Field

There are a few reports of minor infestations of armyworm in corn and grass hay. Aaron Gabriel (CCE Capital District) found corn rootworm beetles and feeding on corn leaves. Corn rootworm will feed on corn leaves when there is no pollen or corn silks available.

Aaron is also finding leptosphaeria (lepto) leaf sport on alfalfa. Lepto leaf spot is a common foliar disease during cool weather, particularly as the alfalfa becomes taller and the canopy closes. Lepto leaf spot primarily attacks young leaflets but may also attack petioles and other plant parts.  It is often observed in the cool moist conditions associated with early spring and late summer to early fall.   Lesions generally start as small black spots and enlarge to oval or round “eyespots” 1/16 to 1/8 of an inch in diameter.  The lesions typically have a light brown to tan center and darker brown borders, often surrounded by a chlorotic (yellow) area. Photo of lepto leaf spot: http://www.ent.iastate.edu/imagegal/plantpath/alfalfa/leptoleafspot/1785.16lepto.html

Justin O’Dea (CCE Ulster County) reports finding ergot on rye. Ergot (Claviceps purpurea) is a disease that can cause field losses in rye. Many cultivars have resistance to the disease. Ergot is also toxic to humans and other animals. Ergot infects the grain kernels of cereal grains and grass plants. Where the kernel should be is replaced by a purplish-black sclerotium referred to as an ergot. For a photo of ergot visit this page: http://www.beefresearch.ca/blog/wp-content/uploads/2013/09/ergot-rye-UoG.jpg

Jeff miller (Oneida County CCE) reports finding eye spot on corn. See past article on eye spot:  http://blogs.cornell.edu/ipmwpr/2014/07/10/nys-ipm-weekly-field-crops-pest-report-july-10-2104/

Reports of the capture of western bean cutworm moths in pheromone traps have increased this week. Northern NY reports high level of captures but the rest of the state have increased as well. See article below for more information. 

Ken Wise (NYS IPM) reports finding downy mildew on soybeans in Dutchess County. He also found minor amounts of gray leaf spot in field corn. See articles below for more information on these 2 diseases. During a barn fly IPM meeting in Orange County on July 30 he found a lot of stable flies attacking the legs of dairy cattle. Horn and face flies were also observed on dairy heifers outside the barn. 

Bill Verbeten (CCE Northeast Dairy and Field Crops Team) reports that many producers have been spraying fungicide for white mold on soybeans. He also reports that some producers have sprayed soybeans for soybean aphid control.

Weather Outlook – July 24 2014

NOAA Northeast Regional Climate Center, Cornell University

Jessica Spaccio (Rennells)

Last week temperatures ranged from normal to 4 degrees below normal. Most areas received half an inch to 3 inches of precipitation; isolated southern areas had less than half an inch, and areas of western NY had 3 to 4 inches.  Base 50 growing degree-days ranged from 70 to 150. Summer-like temperatures will return, but a majority of the forecast period carries a chance for showers and thunderstorms. Today will be mostly cloudy with scattered showers and thunderstorms likely, with some having small hail, strong winds, and heavy rain.  Highs will be throughout the 70’s with sunshine possible late in the day.  Overnight temperatures will be in the 50’s. Friday summer weather will return with mostly sunny skies and highs in the upper 70’s to mid 80’s.  An afternoon shower or thunderstorm can’t be ruled out.  Low temperatures will be in the upper 50’s and low 60’s. Saturday will be mostly cloudy with temperatures in the mid 70’s to low 80’s and scattered showers and thunderstorms.  Overnight temperatures will be in the upper 50’s and low 60’s. Sunday will be mostly cloudy with temperatures in the mid 70’s to low 80’s and scattered showers and thunderstorms.  Overnight temperatures will be in the upper 50’s and low 60’s. Monday will be mostly sunny and dry with highs in the low 80’s.  Overnight temperatures will be in the mid 50’s to low 60’s. Tuesday will be partly sunny with highs in the upper 70’s to low 80’s with showers and thunderstorms possible.  Lows will be in the upper 50’s and low 60’s. Wednesday’s highs will be in the mid to upper 70’s.  Lows will be in the upper 50’s and low 60’s. The five-day precipitation amounts will range from ½ ” to 1”; 7-day amounts will range from ¾ ” to 1 ½” . The 8-14 day outlook (Aug 7 – 13) is showing below normal temperatures for western NY and above normal precipitation.

Maps of 8-14 day outlooks

National Weather Service watch/warnings map

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

Downy Mildew in Soybeans

Ken Wise-NYS IPM

Downy mildew is a common disease of soybeans and only occasionally can cause yield losses. This disease proliferates under high humidity and cool temperatures. The fungus can overwinter on last season crop residue and can the transmitted by seed. Fungal spores are transmitted to the plant by wind and rain. When conditions are right the disease can spread quickly through a field. If the seed was infected with downy mildew the seeding will also be infected. Downy mildew is a biotrophic organism. This means that the disease can only grow and reproduce in associated with soybeans. The disease can have rapid genetic changes in response to the genetic changes to the soybean plant because of this close relationship. There are many different races of this disease and it is monitored closely when new cultivars are being breed. The first sign of the disease are pale green or light yellow spots on the upper leaves. As the disease progresses the spots will enlarge into varying shapes and sizes. Next, lesions show on lower leaf surfaces, particularly in moist weather. The leaves will yellow and become dusted with gray or purplish mildew. Severely infected leaves may curl turn brown, and drop off prematurely. The pods can be infected without obvious external symptoms. Infected seed appear dull white and partly or completely covered with a pale coating of fungal spores.

Downy Mildew

Downy Mildew

Management:

  1. Use certified disease-free seed. If you use seed that is not certified are saved seed from your previous harvests many contain the pathogens we discussed earlier.
  2. Use resistant cultivars; ask your dealer how cultivars compare for disease susceptibility or resistance and productivity. Make sure the cultivar is suitable for your specific region of the state.
  3. Use a fungicide seed treatment at planting. This will kill pathogens that might infect the seed at planting. If you are organic make sure the soil temperature is over 500F. This will allow the soybean to grow quickly and avoid pathogens in the soil.
  4. Plow infected residue under the soil surface. This will help reduce the amount of disease laying on the surface that can infect the next crop.
  5. Foliar fungicides are seldom warranted in New York, But sometimes despite our best efforts a fungicide is needed. If you need to select a fungicide please consult the Cornell Guide for Integrated Field Crop Management

Gray Leaf Spot in Field Corn

Ken Wise, Cornell University-NYS IPM

Gray leaf spot is starting to show up in corn in eastern and central NY. 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.

 

Gray Leaf Spot

Gray Leaf Spot

Management of Gray Leaf Spot

  1. Select corn hybrid with at least moderate resistance to gray leaf spot.
  2. Crop rotation and tillage is an effective method to control the fungus.
  3. Fungicides may be needed to prevent significant loss when plants are infected early and environmental conditions favor disease. Since economic return on foliar fungicide investment is still poorly understood, growers who apply fungicide are urged to leave non-sprayed strips in their fields for comparison of yield and disease severity.

Western Bean Cutworm Update:

Keith Waldron, NYS IPM

Western bean cutworm catches increased significantly in many traps reporting across NY resulting in a 7-fold increase in total moths captured this week. Eighty-seven % of the 56 traps reporting caught at least 1 moth. Trap catch numbers ranged from 0 to 248 moths per trap this week. Ten traps have caught 80 or more moths so far this season. Locations where moth counts are approaching or exceeding an accumulation of 100 moths per trap should be monitored for presence of egg masses and WBC larvae. Ontario and Michigan entomologists recommend checking 10 consecutive plants in at least 5 random locations in the field. The threshold guideline for treating field corn for WBC’s is when 5% of plants are infested with WBC egg masses. For dry beans it is suggested that fields be monitored for signs of pod damage when nearby WBC trap catches approach 100 WBC’s per trap or local corn fields reach threshold. Further details regarding monitoring for WBC can be found in last weeks Pest Report (http://blogs.cornell.edu/ipmwpr/2014/07/25/nys-ipm-weekly-field-crops-pest-report-july-25-2104/). Pictures of WBC larvae and moths including look-a-like moths and larvae can be found at: http://www.msuent.com/assets/pdf/07WBCID.pdf and http://www.cornpest.ca/index.cfm/wbc-trap-network/wbc-scouting-and-training-material-presentations/wbc-and-its-look-alikes/

Western Bean Cutworm Trap Catch – NYS 2014.

6/22

6/29

7/6

7/13

7/20

7/27

Traps Reporting

37

43

62

65

55

58

WBC Total

0

0

8

49

327

2322

Avg WBC / Trap

0.00

0.00

0.13

0.75

5.95

40.03

“0” WBC

37

43

54

38

12

7

> 0 WBC

0

0

8

27

43

51

% Traps Catching

0.00%

12.90%

41.54%

78.18%

87.93%

 

WBCWJuly31

Based on our WBC monitoring experience since 2010, we expect peak WBC flights to occur this week or next. We are collaborating with Penn State University and University of Vermont researchers to test use of a University of Nebraska WBC emergence prediction model. This model is based on the accumulated degree days (DD) from May 1st using 50 F as a base temperature. The Nebraska model predicts 25% moth emergence at 1319 accumulated degree-days, 50% emergence @ 1422 DD and 675% emergence @ 1536 DD. Our accumulated growing degrees (base 50 F) since May 1st appear in the map below.

GDD

Source: Jessica Spaccio, NOAA Northeast Regional Climate Center, Cornell University

 2014 NYS Western Bean Cutworm Trap Catch Data by location.

County City

6/22

6/29

7/6

7/13

7/20

7/27

Total

Allegany Belmont

0

0

1

2

9

38

50

Allegany Caneadea

0

0

0

1

0

10

11

Cattaraugus Randolph

NA

NA

0

0

NA

NA

0

Cayuga Auburn

NA

NA

0

0

0

5

5

Cayuga Aurora

0

0

0

0

NA

NA

0

Chautauqua Clymer

NA

NA

0

0

NA

NA

0

Clinton Chazy

0

NA

0

0

3

NA

3

Columbia Valatie

NA

NA

0

1

0

3

4

Cortland Homer

NA

0

0

1

10

9

20

Delaware Oneonta

0

0

0

0

13

10

23

Delaware Walton

0

0

0

0

2

8

10

Dutchess Amenia

NA

NA

0

0

0

1

1

Dutchess Amenia/Millbrook

0

0

0

0

1

2

3

Essex Willsboro

0

NA

0

1

17

NA

18

Franklin Bangor

0

0

0

3

7

4

14

Franklin Malone

0

0

0

0

2

73

75

Franklin Moira

0

0

0

0

4

85

89

Genesee Stafford

0

0

0

0

6

26

32

Jefferson Calcium

0

0

0

1

0

31

32

Jefferson Chaumont

NA

0

0

2

10

59

71

Jefferson Ellisburg

0

0

0

0

0

0

0

Jefferson Evans Mills

0

0

0

0

2

28

30

Jefferson Hounsfield

0

0

0

0

28

162

190

Jefferson Plessis

NA

NA

NA

2

13

62

77

Jefferson Rodman

0

0

0

0

1

2

3

Jefferson Rutland

0

0

0

0

1

2

3

Lewis Croghan

0

0

0

0

7

248

255

Lewis Denmark

0

0

0

0

4

63

67

Lewis Harrisburg

0

0

1

1

15

28

45

Lewis Lowville

NA

0

1

1

1

45

48

Lewis Martinsburg

0

0

1

0

8

134

143

Lewis Turin

0

0

0

0

14

79

93

Lewis Turin

0

0

0

1

2

57

60

Livingston Caledonia

0

0

0

0

0

1

1

Livingston Groveland

0

0

0

0

0

0

0

Monroe Hamlin

NA

NA

0

6

NA

80

86

Monroe Spencerport

0

0

0

2

6

2

10

Montgomery

Palatine Bridge

NA

NA

1

0

7

56

64

Niagara Barker

NA

NA

0

1

NA

96

97

Oneida Clinton

0

0

0

0

0

NA

0

Onondaga Tully

0

0

0

0

NA

NA

0

Ontario Farmington

NA

NA

NA

0

5

12

17

Ontario Geneva

0

0

0

2

5

16

23

Ontario Hopewell

NA

0

0

1

18

10

29

Orange Warwick

NA

0

0

0

3

0

3

Orleans Kendall

NA

NA

0

1

NA

36

37

Rensselaer Brunswick

NA

0

0

0

NA

0

0

Schuyler Valois

0

0

1

1

12

42

56

St. Lawrence Lawrence

NA

NA

0

1

18

152

171

St. Lawrence Morristown

NA

NA

0

2

2

32

36

St. Lawrence Parishville

NA

NA

0

0

1

68

69

St.Lawrence Heuvelton

NA

NA

0

2

NA

70

72

St.Lawrence Madrid

NA

NA

1

0

2

111

114

St.Lawrence Waddington

NA

NA

0

0

0

29

29

Steuben Wayland

0

0

0

2

12

26

40

Steuben Wayland

NA

0

0

0

NA

NA

0

Suffolk Riverhead

0

0

0

0

1

0

1

Tompkins Varna

0

0

1

4

7

23

35

Ulster New Paltz

0

0

0

0

1

0

1

Ulster New Paltz

0

0

0

0

1

1

2

Washington

Easton

0

0

0

NA

7

3

10

Wayne Alloway

NA

NA

NA

0

0

2

2

Wayne Lyons

NA

NA

NA

0

0

0

0

Wayne Willliamson

NA

NA

0

2

NA

23

25

Wyoming Attica

NA

NA

0

4

38

118

160

Wyoming Wyoming

NA

0

0

1

1

39

41

See also: Sweet Corn Pheromone Trap Network Report. http://sweetcorn.nysipm.cornell.edu/2014/07/29/wny-sweet-corn-trap-network-report-7-29-14/

Clipboard Checklist

Keith Waldron, NYS IPM

 General

*Walk fields to check general field condition, weed issues

*Watch for crop maturity, stand assessments, weed escapes, lodging issues

Alfalfa:

*Evaluate established legume stands for approximate days until harvest
*Monitor potato leafhopper
*Monitor new seedings for potato leafhopper, pythium blight, phytopthora root rot.

Small Grains:
*Monitor spring grain fields for growth stage, disease issues

  Corn:

*Monitor for mid to late season corn pests including European corn borer, armyworm, corn rootworm larvae/adults, foliar diseases, weed issues, vertebrate (birds, deer) damage

 Soybeans:

*Conduct mid season pest assessment including soybean aphid, white mold and other diseases, weed issues, vertebrate damage

  Pastures:

*Check crop growth
*Review/Plan rotation system

*Check and mend fences as needed.

*Invasive species, plants harmful to livestock

 Storage:

*Check grain storage bins for temperature, moisture and signs of mold and insects. Aerate, core, transfer grain or treat as necessary
*
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
*Mow around storage bins and facility to minimize pest hiding places

 Dairy Cattle Barn Fly Management:

*Monitor animals and barn area for house fly, stable fly and other pest management needs including presence of rodents and birds.
*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 throughout barn
*Use, replenish, replace fly management materials: sticky fly tapes/ribbons, insecticide baits, natural enemies (parasitoids), fly population monitoring (3 x 5) spot cards
*Consider purchase and release of Muscidifurax raptor and/or M. raptorellus natural enemies of house and stable fly pupae.

 Dairy Cattle on Pasture:

*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 per animal side, 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 exercise yard.
*Check pasture for forage quality / quantity, rotate as appropriate
*Check pasture for vegetation poisonous to livestock
*Consider use of pasture fly traps to help reduce deer, horse and stable fly populations