September 24, 2013

NYS IPM Weekly Field Crops Pest Report, September 23, 2013

Follow us on Twitter: @NYSFieldCropIPM

In this issue:

  1. View from the Field
  2. Weather Outlook
  3. Corn Rootworm Resistant to (Cry3Bb1) Bt hybrid detected in Cayuga County
  4. Clipboard Checklist

View from the Field

 At a field corn meeting in Orange County this week I observed a moderate level of Northern Corn Leaf Blight and Grey Leaf Spot. There was a lot of Northern corn leaf blight on late planted corn at the Cornell Research Farm in Valatie.

return to top

 Weather Outlook – September 19, 2013

NOAA Northeast Regional Climate Center, Cornell University

Last weeks temperatures ranged from 0 to 6 degrees below normal.  Precipitation ranged from a trace to 2”.  The base 50 growing degree-days ranged from 25-75. Cold front will bring showers and unsettled weather Friday evening to Sunday; next week will by dry and seasonable. Today will be sunny with highs in the mid to upper 70’s.  Tonight’s temperatures will be in the upper 40’s and low 50’s. Friday will be mostly sunny with highs in the upper 70’s to low 80’s.  Afternoon showers and thunderstorms are possible in western NY.  Overnight temperatures will be warm in the upper 50’s and low 60’s. Saturday will be mostly cloudy with highs in the upper 60’s to low 70’s.  Rain and thunderstorms are likely over western to central NY as a cold front moves through.  Lows will be in the low to mid 50’s. Sunday’s highs will be throughout the 60’s with clearing skies in western NY but the front and associated showers moving east over the state.  Lows will be throughout the 40’s. Monday will be partly sunny with highs throughout the 60’s.  Lows will be in the mid to upper 40’s. Tuesday be mostly sunny with highs in the mid to upper 60’s.  Lows will be in the upper 30’s to mid 40’s. Wednesday temperatures will be in the mid to upper 60’s.  Lows will be in the 40’s.

The five-day precipitation amounts will range from ¼” to 2”. The 8-14 day out look (Sep 26 – October 2) is showing above normal temperatures and normal precipitation.

Maps of 8-14 day outlooks

National Weather Service watch/warning map

NRCC Drought Page which features the US Drought Monitor map 

return to top

Corn Rootworm Resistant to (Cry3Bb1) Bt hybrid detected in Cayuga County

Keith Waldron, NYS IPM

 This week Elson Shields reported a corn field in Cayuga County showing symptoms of a failed corn rootworm (Cry3Bb1) Bt hybrid. The field planted to a Monsanto VT3 single event Bt hybrid has extensive goose necking, lodging and severely pruned roots characteristic of corn rootworm (CRW) injury.


Aerial view of CRW resistant Bt corn hybrid field damaged by corn rootworm, Cayuga County, NY. Photos by Elson Shields, Cornell Entomology.

Performance problems with Cry3Bb1 were first reported in the Minnesota and Iowa in 2009 (and Nebraska since 2007). Since then similar reports have emerged from locations in Colorado, Illinois, Kansas, Missouri, Nebraska, South Dakota, and Wisconsin. This recent sighting in New York is among our first in the northeast. The following information is drawn from the Cornell and Penn State articles cited below.

Problem fields share the following characteristics:

  • Planting corn continuously for multiple years (typically more than four years)
  • Using the same (Cry3Bb1) Bt trait year after year as a single event.
  • Refuge compliance was (often) problematic (no/not enough refuge, or refuge too far from the Bt field) on farms with unexpected damage.

Warning signs of potential corn rootworm resistance:

  • Large number of CRW beetles in the field, possibly leaf feeding, clipped silks resulting in poor pollination.(this is a very weak indicator since the beetles are strong fliers)
  • Unexpected lodging and root damage that cannot be explained by an agronomic or environmental problem, or presence of another root-feeding pest.

Recommendations to reduce the selection pressure on corn rootworm to develop resistance to CRW-BT corn:

  • ROTATE-ROTATE–ROTATE corn with non-host crops such as alfalfa, soybeans, small grains.
  • Fields with low levels of CRW pressure should be planted to a non-CRW-BT variety. These fields are typically first or second year fields. First year fields do not need any rootworm insecticide, but second year fields may need a high rate of seed treatment or a reduced rate of soil insecticide.
  • Only plant CRW-BT corn varieties in fields with high rootworm pressure. These fields are typically continuous corn fields in 3 or longer years of continuous corn.

For more information see:

Corn Rootworm Resistance to BT-Corn Reported

 Managing Western Corn Rootworm Resistance to Bt on the Fringe

return to top

Clipboard Checklist

Keith Waldron, NYS IPM


*Walk fields to check general field condition, weed issues, areas of soil erosion

*Evaluate established legume stands for approximate days till harvest
*Monitor alfalfa regrowth for potato leafhopper (PLH)
*Monitor new seedings for PLH, Pythium blight and Phytopthora Rot.


*Conduct late-season corn pests including European corn borer, foliar diseases such as northern corn leaf blight, gray leaf spot, eyespot, ear mold, weed issues, vertebrate damage
*Be on the lookout for possible larval feeding by Western Bean Cutworm in corn ears (and dry bean pods)
*Evaluate corn to estimate days to silage harvest


*Conduct late-season soybean pests such as soybean aphid, white mold, soybean vein necrosis virus and other diseases, weed issues, vertebrate damage
*Monitor for late season infestations of Brown Marmorated Stink Bug around field margins


*Check and mend fences as needed.
*Check crop growth
*Monitor for invasive species, plants harmful to livestock
*Review/Plan rotation system


*Check and prepare equipment for upcoming harvests
*Maintain pesticide use records


*Clean and sanitize empty grain bins in advance to receive upcoming soybean or corn grain harvest
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 harborage and pest hiding places
*Check stored grain bins for temperature, moisture and signs of mold and insects. Aerate, core, transfer grain or treat as necessary

 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

return to top