July 14, 2017

NYS IPM Weekly Field Crops Pest Report, July 14, 2017

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Volume 16 -Number 11

View from the Field

Potato Leafhopper

Potato Leafhopper (Empoasca fabae)(PLH)  populations in alfalfa are extremely high across the state. Many fields are reporting PLH over threshold and showing damage.  In one field I had an average of 400 PLH nymphs per sample. This is a VERY high infestation rate in alfalfa. Make sure to check your fields ASAP.

Potato Leafhopper Nymphs

Potato Leafhopper Adult

Potato Leafhopper Damage to Alfalfa

We have a training video on IPM for Potato Leafhopper in Alfalfa (8 minutes long). The video helps you understand how to monitor and determine thresholds for potato leafhopper. It also has IPM methods of control of potato leafhopper including harvesting early, planting resistant cultivars and insecticides.   IPM For Potato Leafhopper in Alfalfa

Black Cutworm

I am finding black cutworm damage to field corn at the Cornell Farm in Valatie. A few weeks ago we had 60 black cutworm moths in a pheromone trap at the farm. The field still had less than 5%  damage. If you have later planted corn and the field had weedy grasses you might want to check for black cutworm damage.

Black Cutworm Damage to field corn

Black Cutworm

NYS Western Bean Cutworm Report for Field Corn 2017

The 2017 Western Bean Cutworm (WBC) Monitoring program is underway and WBC moth collections have begun. Western Bean Cutworm (WBC) is an emerging pest in NY with the potential to cause substantial damage to corn, Zea mays and beans, Phaseolus vulgaris. WBC is native to North America and has historically been a pest of corn and dry beans in the high plains region of the western US.  WBC larvae feed on developing corn kernels, bean pods and seeds. Larval feeding damage causes direct yield losses and can increase subsequent risk of ear mold issues including infection by mycotoxin producing fungi.

WBC moths were first confirmed in Pennsylvania and western New York in 2009, one year after they had been detected in Ontario, Canada.  Extensive monitoring during 2010 – 2016 has determined that WBC moths are well distributed across these areas and have expanded their range into Quebec and parts of Northeast.

NY WBC populations have increased annually since statewide until last season. In 2016 WBC data was available from 63 traps across NY. A total of 17,450 WBC moths were collected in 2016, compared to 20,844 collected in 2015, and 11,353 collected in 2014. On average, higher WBC counts have been observed in northern and western counties with the majority of high captures occurring in locations north of the NYS thruway (Interstate 90). The number of moths caught on average per traps in 2014 was 177 moths/trap and in 2015 was 266 moths/trap. Note that while the total number of moths caught were down from 2015 the 2016 the average of 277 moths/trap was higher than in 2015.


There were reports of WBC causing economic damage in NY in field corn in Northern NY in 2016.  In some cases 20% of the ears of corn were damaged in field corn. WBC also caused damage to certain Bt hybrid corn cultivars in Northern NY.


Table 1. New York Western Bean Cutworm 2010 – 2016 Collection Data Summary*

  2010 2011 2012 2013 2014 2015 2016
No. Counties 29 37 44 39 41 39 26
No. Traps 54 67 88 89 96 91 63
Avg. No. WBC / Location 13 23 42 66 117 266 277
Range in Totals 0 – 99 0 – 165 0 – 344 0 – 853 0 – 1019 0 – 1688 0-1662
Peak Flight 2-Aug 2-Aug 25-Jul 21-28-Jul 3 – Aug 2 – Aug Aug 7

*Data compiled from WBC trap catch information provided by field corn, sweet corn, and dry bean monitoring networks across NY. In 2016 the data is just related to field corn.


To keep watch on WBC populations and help determine this season’s risk of potential impact WBC pheromone traps are again being monitored across the state by a dedicated network of cooperative extension, agricultural consultant and producer volunteers. WBC trap deployment began in June. WBC numbers are beginning to trickle in indicating moth emergence has begun. Peak WBC moth flight activity is anticipated towards the end of July or early August. Accumulated moth captures as of 7.14.17 from field corn monitoring sites are shown below.


 Week of: 6/18/2017 6/25/2017 7/2/2017 7/9/2017
Traps Reporting 14 16 25 26
WBC Total 0 7 19 40
Avg WBC / Trap 0.0 0.4 0.8 1.5
“0” WBC 14 12 18 13
> 0 WBC 0 4 7 13
% Traps Catching 0.0% 25 % 25.5% 50%

Western bean cutworm updates for sweet corn and dry beans will be available at this blog throughout the season and the NYS IPM Sweet Corn Pheromone Trap Network Report.

Degree Day Models for Field Crops across New York

Ken Wise, NYS IPM

 Seed Corn Maggot Peak Flight and Fly Maggot Free Degree Days

Base Temp = 390 F Peak 1st Generation Seed Corn Maggot Fly Free degree days Peak 2nd Generation Seed Corn Maggot fly Free degree days Peak 3rd Generation Seed Corn Maggot fly Free degree days
degree days 360 810 1,080 1530 1800 2250

Source: Insect IPM for Organic Field Crops: Seed Corn Maggot by Katelin Holm and Eileen Cullen


Black Cutworm Degree Day Model

Degree Days                Stage                                      Feeding Activity

0                      Moth Capture                      Egg Laying

90                   Eggs Hatch

91-311           1st to 3rd Instar   Leaf Feeding

312-364         4th Instar                              Cutting Begins

365-430         5th Instar                              Cutting Begins

431-640         6th Instar                              Cutting Slows

641-989         Pupa                                       No feeding

Source: University of Minnesota Black Cutworm Trapping Network




Clipboard Checklist

Keith Waldron, NYS IPM 


*Walk fields to check general field condition, weed issues

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



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

Small Grains:
*Monitor spring small grains for signs of Fusarium Head Blight, foliar diseases

*Monitor grain fields for growth stage, disease and lodging issues, grain maturity, harvest timing
*Record diseases present, location and types of weed escapes


Monitor for mid-season corn pests including European corn borer, corn rootworm, western bean cutworm, slugs, foliar diseases such as northern corn leaf blight and gray leaf spot, weed issues, nutrient deficiencies, vertebrate damage.


*Monitor for crop growth stage, soybean aphid, defoliators, foliar diseases, white mold, weed issues, vertebrate damage


Check water sources, mend fences as needed.
*Check crop growth, clip pastures between grazing as needed
*Monitor for invasive species, plants harmful to livestock
*Review/Plan rotations


* Check stored grain bins for temperature, moisture and signs of mold and insects. Aerate, core, transfer grain or treat as necessary

* Clean and disinfect empty storage bins in preparation for grain harvest
Check forage allocation and anticipate feed program adjustments as forages from previous year are used up
*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