Cornell Field Crops News

Timely Field Crops information for the New York Agricultural Community

May 20, 2019
by Cornell Field Crops
Comments Off on NYS IPM Weekly Field Crops Pest Report – May 20, 2019

NYS IPM Weekly Field Crops Pest Report – May 20, 2019

May 15, 2019
by Cornell Field Crops
Comments Off on Waterhemp Herbicide Resistance Tests: Preliminary results

Waterhemp Herbicide Resistance Tests: Preliminary results

Bryan Brown, New York State Integrated Pest Management
Collaborators: Antonio DiTommaso, Kathleen Howard, Mike Hunter, Jeff Miller, Scott Morris, Jodi Putman, Peter Sikkema, Mike Stanyard

Waterhemp seedlings in greenhouse

Bryan Brown is coordinating a project testing waterhemp for resistance to herbicides.

Last summer, several populations of waterhemp (Amaranthus tuberculatus) survived herbicide applications in western NY corn and soybeans.

Growers asked if these weeds are actually resistant to certain herbicides. If so, which ones? And are all populations of western NY waterhemp resistant to the same herbicides, or do they differ?

To answer these questions, we collected seed from these surviving weeds at three locations in NY, grew them in a Cornell University greenhouse alongside a population of waterhemp that we know is susceptible to herbicides, and then used a spray chamber to apply a range of herbicides and rates.

The herbicides we used were glyphosate (i.e. Roundup, WSSA Group 9), atrazine (i.e. Aatrex, WSSA Group 5), lactofen (i.e. Cobra, WSSA Group 14), and imazethapyr (i.e. Pursuit, WSSA Group 2). The WSSA groups represented here are the ones waterhemp has developed the most resistance to in other states. For each herbicide, we used five different rates. Each rate was applied to five waterhemp plants from each population. Following the methods of other studies, plants were sprayed when they were around 5” tall. BASF Agricultural Solutions and Valent USA LLC supplied some of the materials for this study.

We’ll be doing a final analysis three weeks after spraying. But here’s how the NY populations look after only one week. At the full labelled rates, glyphosate resulted in 50% control and lactofen resulted in 99% control. Atrazine and imazethapyr resulted in poor control, but waterhemp plants were larger than the maximum size stated on the label.

But it’s the comparison of our three NY populations to the susceptible population that determines resistance. Final control ratings will be done in two weeks, but initial results indicate that two NY populations are potentially resistant to glyphosate, three are potentially resistant to atrazine, none are likely resistant to lactofen, and two are potentially resistant to imazethapyr. So herbicides in WSSA Groups 2, 9, and 5 shouldn’t be solely relied upon to control this weed.

Since there were some differences between NY populations, we’ve shared each farm’s results with the participating growers so they can make the necessary changes to their management plans.

So if you haven’t seen it already, keep an eye out for waterhemp this year. It looks similar to other NY pigweeds, except that it’s completely hairless and it has separate male (pollen-producing) and female (seed-producing) flowering heads. (A video comparison may be found from American Agriculturalist.) Since it can travel in seed, feed, and equipment ­– make sure they’re clean. And think about trying out some new weed control options.

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April 10, 2018
by Cornell Field Crops
Comments Off on New Weed Control Options in Winter Wheat and Barley for NYS

New Weed Control Options in Winter Wheat and Barley for NYS

By Mike Stanyard, NWNY Dairy, Livestock & Field Crops Team – Field Crops Specialist and Team Leader

It has always been encouraged to spray the earliest planted fields for winter annual weeds (purple deadnettle, chickweed, chamomile) in late fall. However, there are so many other things going on in the fall and your windows of opportunity for spraying can be slim to none. You never know what the weather will be like in the spring and timely weed control can be tricky. Here is an update on broadleaf and grass control products for this spring with two new products just registered in 2018.

Broadleaf Weeds. Harmony Extra and Harmony SC are still the backbone of many spray programs. Harmony Extra (Harmony + Express), controls a wider range of broadleaves and it is favored over other products because of its control of corn chamomile, wild garlic and chickweed. A recent point of concern has been the number of marestail/horseweed plants that are making it through until harvest. This may be an indication that you have an ALS resistant marestail population. Both of these products can be applied up until the flag leaf is visible (before Feeke’s stage 8).

Growth regulator products like Clarity, Banvel, MCPA and 2,4,-D are effective against many broadleaves and should take care of ALS resistant marestail. They are usually tankmixed with Harmony products for extra control of winter annuals and perennials. Application past Feek’s stage 6 (jointing) is not advised as it could lead to plant injury and yield reductions. Unfortunately, I have seen annual marestail emerge after this stage.

Huskie (Bayer Crop Science) just received a 24(c) Special Local Needs label for New York on March 2nd. It is a combination of pyrasulfotole (an active not labeled in NY yet) and two formulations of bromoxynil (ie Buctril). The SLN labeling is for marestail/horseweed control in wheat, barley, rye and triticale. Huskie can be used for control of marestail in winter malt barley as well. Talking with Dwight Lingenfelter, Penn State weed scientist, Huskie would be best tank-mixed with Harmony Extra for complete broadleaf control. In fallow ground trials over the past two seasons, Penn State has been seeing (90-95%) control of 8 inch marestail with Huskie at the highest rate. Huskie can be applied up until flag leaf emergence.

Grasses. NYS has a 24(c) Special Local Needs label for Osprey for control of roughstalk bluegrass and cheat in winter wheat. It expires at the end of 2018. Osprey can be applied in the fall and spring but must be applied early in the spring, prior to the jointing stage in winter wheat.

Prowl H2O can be applied to wheat and triticale in the fall and the spring but must be applied before weed seeds germinate. It is very effective on our annual grass spectrum and some of our annual broadleaves but must be applied early in the spring prior to weed emergence.

Axial XL (Syngenta) was just registered on January 12 in NYS and is labeled for the control of grasses in wheat and barley. The active ingredient is pinoxaden which is in Group 1 (ACCase mode of action). Axial can be applied to wheat and barley from the 2-leaf stage to pre-boot stage. It is labeled for Foxtail (giant, green and yellow), volunteer and wild oats, annual ryegrass, barnyardgrass and canarygrass. Axial XL can be used for annual grass control (foxtails most importantly) in spring malt barley. For optimal control, it is recommended to apply when grasses have between 1 and 5 leaves on the main stem or prior to emergence of the 3rd tiller. THIS PRODUCT IS NOT LABELED FOR OATS!!!

We are still advising growers not to mix your herbicide and nitrogen applications and spray separately. The leaf burning can cost us up to 10 bushels and could get worse as temperature and humidity increase.

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June 30, 2017
by Cornell Field Crops
Comments Off on Oneida County Scouting Report – June 30, 2017

Oneida County Scouting Report – June 30, 2017

This week’s crop report (PDF).

The main issue is potato leaf hopper numbers over threshold in heavy alfalfa fields.
The second major issue is the potential for DON in wheat this year. Setting combines to blow out infected kernels and sampling for DON analysis.

Many soybean fields will need herbicide application soon

Many corn fields will need to be side dressed with N soon.

Jeffrey J. Miller
Cornell Cooperative Extension Oneida County
Ag Program Leader
121 Second St., Oriskany, NY 13424

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August 2, 2016
by Cornell Field Crops
Comments Off on Help locate Johnsongrass populations in New York State

Help locate Johnsongrass populations in New York State

Professor Toni DiTommaso is working on a nation-wide research project assessing the distribution and genetic diversity of the invasive perennial weed, Johnsongrass (Sorghum halepense). Currently, NY State is at the geographic northern-most limit of its range, but it is expected to increase in abundance in the state over the coming decades. He has included a brief description and several images of this species below to help with identification in case you are not familiar with it.

He is reaching out to you to help him locate Johnsongrass populations in NY State as he would like to collect seeds from these plants later this month and into early fall. These seeds along with seeds collected in other regions of the country will be grown in “common gardens” at locations across the country including here in central NY. This research will give us a good idea of how well adapted different populations of this invasive species are to growing in various regions of the country and in which regions it may become especially troublesome to manage.

If you know of Johnsongrass populations in NY State that have not yet been killed by herbicides or mowed (he needs to collect seeds), please e-mail Toni ( the precise location of the population (GPS coordinates, road intersections, etc.), the type of habitat it is found in (e.g. corn field, roadside, back of barn), and the approximate size of the population(s) (e.g. 10 ft x 15 ft). If you would like to take a few pictures of the plants and e-mail them to Toni, he could try to confirm that it is indeed Johnsongrass.

When this research is completed in a few years, he hopes to present his findings at various agricultural extension venues in the State.

Thank you for your help and he looks forward to hearing from you.

Toni DiTommaso (
Weed Ecology & Management Lab
Soil and Crop Sciences
903 Bradfield Hall
Cornell University

BRIEF DESCRIPTION: Johnsongrass is a tall, coarse, grass with stout rhizomes. It grows in dense clumps or nearly solid stands and can reach 8 feet (2.4 meters) in height. Leaves are smooth, 6-20 inches (15.2-50.8 cm) long, and have a white midvein. Stems are pink to rusty red near the base. Panicles are large, loosely branched, purplish, and hairy. Spikelets occur in pairs or threes and each has a conspicuous awn. Seeds are reddish-brown and nearly 1/8 inch (0.3 cm) long.

Johnsongrass plants in flower

Mature Johnsongrass plants in flower

Johnsongrass seedheads 1


Johnsongrass seedheads 2







Note the prominent, white, midvein on a mature Johnsongrass leaf (LEFT) and root system with rhizomes (RIGHT)

Note the prominent, white, midvein on a mature Johnsongrass leaf (LEFT) and root system with rhizomes (RIGHT)


The ligules on Johnsongrass leaves (A) are membranous, while the ligules on Fall Panicum leaves (B) are a fringe of hairs. Barnyardgrass (C) lacks ligules.

The ligules on Johnsongrass leaves (A) are membranous, while the ligules on Fall Panicum leaves (B) are a fringe of hairs. Barnyardgrass (C) lacks ligules.




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September 18, 2014
by Cornell Field Crops
Comments Off on NYS IPM Weekly Field Crops Pest Report – September 18, 2014

NYS IPM Weekly Field Crops Pest Report – September 18, 2014

NYSIPMpestreportGet the full issue or subscribe by email to receive notifications of new reports including Videos from the Field.

In this issue:

      • View from the Field
      • Weather Outlook
      • Preventing Weeds Through Pasture Management
      • Alfalfa Snout Beetle in Fall Alfalfa
      • Western Bean Cutworm Update
      • Clipboard Checklist

Twitter Icon  Follow NYS IPM Field Crops on Twitter!

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September 4, 2014
by Cornell Field Crops
Comments Off on Weed Science Society of America – Herbicide Resistance Summit Webcast

Weed Science Society of America – Herbicide Resistance Summit Webcast

The Weed Science Society of America (WSSA) announced the agenda for a national scientific summit on herbicide resistant weeds, scheduled for 9 a.m. to 5 p.m. September 10 in Washington, D.C.  WSSA plans to offer the event as a live webcast for those unable to attend in person.

Those wishing to participate via webcast will find a link posted on September 10 at

Meeting Agenda 

9:00 Welcome by USDA
9:15 Current State, Challenges, Accomplishments
10:00 Understanding the Decision Process
10:45 Break
11:15 Economics of Resistance Management
11:45 Community-Based Approaches to Resistance Management
12:30 Lunch
1:30 Global Perspective on Herbicide Resistance
2:00 Diversifying Weed Management Tactics
2:30 New Approaches to Education and Outreach
3:00 Break
3:30 Incentives and Regulations to Manage Herbicide Resistance
4:00 EPA’s Perspective
4:15 Call to Action

Key action items to be discussed at the Summit include:
• Increase awareness that everyone engaged with agriculture has a role in managing
herbicide resistance and accountability for that role.
• Develop a herbicide resistance management certification program for weed
management decision makers and advisors.
• Reduce regulatory barriers to herbicide resistance management; e.g. conservation
• Establish prototypical, community-based area-wide herbicide resistance
management programs for specific threats; e.g. Palmer amaranth in Iowa.
• Communicate the effect of herbicide resistance management on short and long-term
farm profitability.
• Implement programs for scouting and controlling weed escapes.
• Provide short-term financial incentives to reduce the cost of developing and
implementing field-by-field herbicide resistance management plans.
• Market/promote consistent and scientifically sound herbicide resistance
management programs.
• Incentivize innovation in non-chemical weed management practices.

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July 15, 2014
by Cornell Field Crops
Comments Off on Sneaky Pasture Weeds – Sedges and Rushes

Sneaky Pasture Weeds – Sedges and Rushes

by Kitty O’Neil and Mike Hunter, Regional Field Crops and Soils Specialists

We’ve discussed pasture grasses, legumes, pasture weeds and management ideas for pasture improvement on these pages many times before.  All good topics.  When you call to mind pasture weeds though, I’d bet you picture milkweed, goldenrod, a couple different types of thistles and maybe bedstraw.  These are pesky and important weeds in many pastures, but there are other, sneakier weeds that may escape your attention.  These sly and mischievous weeds require closer inspection and a bit more scrutiny to figure out.

Ideally, pastures are dense, perennial sods consisting of mixtures of high-yielding, palatable grasses and legumes.  In reality, most pastures do not quite match this perfect ideal.  Weeds are normally present in some number, ranging from insignificant to seriously problematic, depending on management and history.  Weed density within a pasture can change over time, and can vary from one area to another within a pasture.  You may notice, in your own pastures or hay fields, that weeds are often not distributed uniformly, but rather that some plant species are concentrated on knolls, along the woods, in wet spots, or in high traffic areas.

A well-managed Northern New York pasture.  (Photo: K. O'Neil, August 2013)

A well-managed Northern New York pasture. (Photo: K. O’Neil, August 2013)

Let’s turn our attention to some particularly sneaky weeds that are often, but not always, found in lower, wetter areas of the pasture – the sedges and rushes.  I’m referring to them as ‘sneaky’ because they’re a bit harder to spot in the pasture.  They look a lot like grasses to an amateur observer, but that is about as far as the similarities extend.  As a group, grasses consist of a jointed stem with a few tillers, long and slender leaves with parallel veins.  They range in height from turf to giant bamboo.  Grasses may be annual or perennial but all have their growing points near the soil surface, so they can survive repeated mowing or grazing.  Grasses reproduce via seed or underground structures.  Most of the hay and pasture grass species (bluegrass, orchardgrass, timothy, fescues, reed canarygrass, etc.) are quite palatable and produce moderate to high yields.

Sedge and rush species also have long slender leaves but occupy completely different branches on the evolutionary tree of life than grasses.  Sedges and rushes are perennials that livestock typically avoid, finding them unpalatable.  There are well over 1000 different sedge species, but the most common sedge found in Northeast pastures and hayfields is Yellow Nutsedge.  Yellow nutsedge is noticeable for its pale green color, spiky flowers and underground tubers, but its most distinctive feature is its stem.  If you compare the lower stems of sedges and grasses, you’ll discover that sedges typically have triangular stems without nodes while grasses have round or flattened stems with nodes.  This key difference is the reason for the memorable phrase “sedges have edges, but grasses have knees.”  Sedges reproduce by underground tubers and rhizomes.

Rushes are short plants that resemble grasses and sedges and are also found in lower, wetter areas of a pasture or hayfield, although rushes may grow in drier or compacted areas too.  The unique feature of rushes is their 3-petal, lily-like flowers.  In fact, botanists refer to rushes as “lilies turned to grass” to help them remember their distinctive flowers.  Rushes reproduce by vegetative rhizomes or by seed.  The tough, wiry, round stems of rushes are also avoided by livestock who generally do not find them palatable.  In the Northeast, the most common of the rushes is Slender Rush.

Nutsedge and rushes might be most noticeable as animals are finished with a pasture or paddock.  The livestock will have eaten grasses and other appealing plants, leaving behind patches of Yellow Nutsedge and Slender Rush.  It is disappointing to see large, uneaten areas of low-yielding, unpalatable pasture, but biological features of rush and sedge make them difficult to control.  Their underground reproductive structures make mowing or clipping ineffective as a means for removal, but this strategy can slow their spread, if it is timed before flowering.  Herbicide options for these two weeds are limited, but Permit and Yukon have recently had hay and pasture applications added to their labels.  They may be used on yellow nutsedge in grass pastures with no grazing restriction for lactating or non-lactating animals.  If the field is not too wet for machinery, suitable grasses or legumes can be overseeded with a no-till drill or, as a more drastic measure, the sod may be killed and soil can be tilled for replanting of appropriate grasses and legumes.  Often though, the sedges and rushes occupy areas that may be difficult to access with tractor equipment.  In this case, the field could be tiled for better drainage if that option is economically advantageous.  Legume species such as red or white clover can be frost-seeded in the spring to try and introduce more desirable species, but the rush and sedge species will likely persist.  Sedge and rush weeds take a keen eye to notice, but their impact can be just as important as thistles or milkweed or goldenrod in a pasture or hayfield.  Their presence reduces overall productivity of the field and presents a challenge to the farm manager.

Additional resources:

  1. Uva, Neal and DiTomaso, Weeds of the Northeast, Ithaca, NY: Cornell University Press, 1997.
  2. Kersbergen, R.  2004. Bulletin #2491, This Old Hayfield: A Fact Sheet on Hayfield Renovation.  U Maine Extension.
  3. Specification Guide Sheet For Pasture and Hay Planting (512), Vermont NRCS
  4. Yukon ( and Permit ( herbicides, Gowan Company.

For more information about field crop and soil management, contact your local Cornell Cooperative Extension office or Kitty O’Neil, Regional Field Crops and Soils Specialist, Cornell University Cooperative Extension, 315-379- 9192 x253;

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May 30, 2014
by Cornell Field Crops
Comments Off on New York Weed Science Field Day – July 16, 2014

New York Weed Science Field Day – July 16, 2014

The Departments of Crop and Soil Sciences and Horticulture along with the Cornell University Agricultural Experiment Station and the Cornell Cooperative Extension will be hosting the annual New York Weed Science Field Day at the H.C. Thompson and Robert B. Musgrave Research Farms.

As always, NYSABA will be hosting a BBQ lunch at Musgrave Farm prior to the Field Crop session.  Pre-registering for the BBQ prior to July 10th saves $3!

Please see the pre-registration forms for contact information with any questions.  CCA and DEC Credits have been requested for field crop and vegetable crop field days.


Freeville, NY (10 miles Northeast of Ithaca, Fall Creek Road, Rt. 366 extension)

Pre-registration for the Vegetable Crop Weed Control session is preferred.

Download the WEED DAY 2014 Registration Form.

8:00 a.m.                         Registration  Coffee (beverage), doughnuts, and informational trial packet ($8.00)

8:30 a.m.-11:30 a.m.      Vegetable Crop Weed Control (Bellinder)



Aurora, NY (1256 Poplar Ridge Road, connects 90 and 34B)

Pre-registration for the Field Crop Weed Control session is not required.

12:00 – 1:30 p.m. NYSABA BBQ lunch at Musgrave Research Farm.  (Download the WEED DAY 2014 BBQ Ticket Request Form)

1:30 p.m.              Registration

2:00 – 5:00 p.m.   Field Crop Weed Control (Hahn)

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