Skip to content

New York State Agencies encourage the public to report findings of the invasive pest, spotted lanternfly. As of August 14, 2020, it was confirmed that spotted lanternfly (SLF), an invasive pest from Asia, has been found on Staten Island. The New York State Departments of Agriculture and Markets (AGM), Environmental Conservation (DEC), and Office of Parks, Recreation and Historic Preservation (OPRHP) confirmed that several live, adult insects were discovered by OPRHP staff in Clay Pit Ponds State Park Preserve. 

Picture of an adult spotted lanternfly on a tree trunk
Spotted lanternfly adult on the trunk or a tree.

AGM urges New Yorkers to report potential sightings using the SLF web reporting tool found here:

This destructive pest feeds on more than 70 plant species, including tree-of-heaven, and plants and crops that are critical to New York’s agricultural economy, such as sugar maple, apple trees, grapevines, and hops. Adults are out now and are strikingly large with black polka dots. They'll be mating, laying eggs, and feeding on sap from August through October and even into December, depending on the onset of frosts. 

State Agriculture Commissioner Richard A. Ball said, “The Department is working closely with its partners at the Department of Environmental Conservation, the State Office of Parks, Recreation and Historic Preservation, and the U.S. Department of Agriculture (USDA) to mitigate the impacts of this destructive pest, which can weaken plants and have a devastating impact on agriculture.  While this find on Staten Island is concerning, New York State has taken strong actions to combat the establishment of SLF since 2017.  We will continue our work to survey and inspect high-risk areas and implement targeted management plans.  We also urge the public to be vigilant and report any suspected sightings of SLF to help slow the spread of this invasive.

DEC Commissioner Basil Seggos said, “Since spotted lanternfly was first discovered in neighboring states, DEC has worked aggressively with the State Department of Agriculture and Markets, Office of Parks, Recreation and Historic Preservation, USDA and other partners to educate New Yorkers and take steps to prevent this invasive species from establishing itself in New York State. This invasive pest has the potential to severely impact and stress New York's forests, agricultural crops, and tourism industries. The first live find on Staten Island is concerning, but our goal remains to find spotted lanternfly early and prevent it from further entering New York State and limiting any serious threats to our natural resources.

State Parks Commissioner Erik Kulleseid said, “Spotted Lanternfly poses a troubling threat to the environment and agriculture of New York State but also to the quality of recreational opportunities and experiences we offer in our State Parks and public lands. I applaud our Parks’ environmental stewardship staff for identifying this pest, so New York State can quickly begin taking steps to slow its spread. Park visitors across the state can help in identifying and reporting this destructive pest, and I urge them to familiarize themselves with its signs.

Following the finding by OPRHP, AGM, working with DEC, OPRHP, and the USDA, immediately began extensive surveys throughout the area.  Crews will continue to survey areas on Staten Island, develop management plans to slow SLF’s spread, and minimize the damage and impact from this invasive species.  AGM urges New Yorkers to report potential sightings using the SLF web reporting tool found here:

SLF feedings can stress plants, making them vulnerable to disease and attacks from other insects. SLF also excretes large amounts of sticky "honeydew," which attracts sooty molds that interfere with plant photosynthesis, negatively affecting the growth and fruit yield of plants, and impacting forest health. SLF also has the potential to significantly hinder quality of life and recreational activities due to the honeydew and the swarms of insects it attracts.

First discovered in Pennsylvania in 2014, SLF has since been found in New Jersey, Maryland, Delaware, West Virginia and Virginia. Given the proximity to the Pennsylvania and New Jersey infestations, New York State is at high risk for infestation.

Since 2017, AGM, DEC, and OPRHP have taken an aggressive approach to keeping SLF from establishing in New York State, conducting surveys of high-risk areas across the State; inspecting nursery stock, stone shipments, and commercial transports from quarantine areas; and launching a comprehensive education and outreach campaign to enlist the public’s help in reporting SLF.

Photo collage showing the life stages of spotted lanternfly.
Life stages of SLF - look for egg masses during winter and early spring, nymphs during spring and summer, and adults in late summer and fall.

While these insects can jump and fly short distances, they spread primarily through human activity. SLF can lay their eggs on any number of surfaces, such as vehicles, stone, rusty metal, outdoor furniture, and firewood. Adult SLF can hitch rides in vehicles, on any outdoor item, or cling to clothing or hats, and be easily transported into and throughout New York.

The public is encouraged to thoroughly inspect vehicles, luggage and gear, and all outdoor items for egg masses and adult SLF before leaving areas with SLF, particularly in the counties of states in the quarantine area—Pennsylvania, New Jersey, Maryland, Delaware, West Virginia and Virginia.   If SLF adults are found, residents should remove them and scrape off all egg masses.

Residents can also help by allowing surveyors access to properties where SLF may be present.  Surveyors will be uniformed and will always provide identification.

Identifying SLF

Adult SLF are active from July to December. They are approximately one-inch long and half an inch wide at rest, with eye-catching wings. Adults begin laying eggs in September. Signs of an SLF infestation may include:

  • Sap oozing or weeping from open wounds on tree trunks, which appear wet and give off fermented odors.
  • One-inch-long egg masses that are brownish-gray, waxy and mud-like when new. Old egg masses are brown and scaly.
  • Massive honeydew build-up under plants, sometimes with black sooty mold developing.

AGM urges New Yorkers to report potential sightings using the SLF web reporting tool found here:

Learn More About SLF

For more Information on Spotted Lanternfly, visit

The NYSIPM program, with AGM and DEC, has been monitoring and preparing for SLF since 2014. Find educational resources, pictures, distribution and quarantine maps, life cycles, guidance for travelers, etc., on the NYSIPM Spotted Lanternfly website,

Press Release Contact:
Jola Szubielski, AGM | | 518-457-0752
Lori Severino, DEC | I 518-402-8000
Dan Keefe, Parks I I 518-486-1868


If you know people in the K-12 community, let them know about this year's IPM Conference, School IPM 2020: Where We've Been and What's Next. A virtual conference taking place on the mornings of August 11 and 18, 2020. Starting this Tuesday, August 11! Where? On Zoom, of course! The cost is only $15 per person or $25 for your entire school district's personnel. Click Here to Register!

This Sixth Annual NYS IPM conference brings together a wide range of speakers to address and discuss the status of school IPM adoption and where we need to go in the future. If you or your family is impacted by pests or pest management on and off school property, this virtual conference is for you.

Cartoon showing pests not gaining access to the school building. Artwork by Karen English, Cornell University.Despite decades of promoting school IPM, bed bugs, cockroaches, lice, and mice continue to be a problem in schools. Part of the issue is lack of implementation of proven IPM techniques such as exclusion. Part of the issue is that some pests, like bed bugs, German cockroaches and lice arrive in backpacks, delivered supplies, and directly on students and staff. While schools often have plans in place to address these pests when they are discovered, it will take a wider community effort to prevent their introductions. Join us and learn about proven school IPM tactics!

Our keynote speaker, Lorraine Maxwell, will discuss “Healthy Environments for Learning”. Her research has found that school building conditions, which include conducive conditions for pests as well as the presence of pests, impact the school’s social climate, which directly impacts student performance. Meet the Keynote Speaker for the School IPM 2020 Conference in this IPM blog by Joellen Lampman, NYS IPM Program's School and Turfgrass IPM Extension Support Specialist.

How: Click Here to Register
Cost: $15 per person or $25 per school district

This table shows the NYS DEC pesticide license recertification credits to be awarded at the School IPM conference.NYS Pesticide Applicator recertification credits have been awarded for the following categories: Core, 3A, 3B, 7A, 7F, and 8.

Individuals seeking credits will need to submit their applicator ID numbers when pre-registering. Further instructions will be sent upon pre-registering.

Spread the word to those you know who work in schools — across New York State and across the country!

Learn more about this year's IPM Conference on the NYS IPM web page, School IPM 2020: Where We've Been and What's Next,

Have a healthy and safe school year, everyone!


Sustained catch in Monroe County marks the end of 2020 SWD monitoring. Please join me in thanking all who contribute to this effort! In the blueberry planting in Monroe County, Janet van Zoeren, CCE Lake Ontario Fruit Program, caught 11 SWD in the week ending July 28 (2 males and 9 females).

You know what you need to do to keep your fruit healthy and free of infestation! If you need a refresher, review the information on the Cornell Fruit Resources SWD management web page,, and learn more about SWD's life cycle to better understand how infestations, once started, can ramp up on the Cornell Fruit Resources SWD biology and life cycle web page,, on to thanking everyone!

New people

These Cornell University scientists participated in SWD monitoring for the first time this year. A special thanks go out to them for braving COVID-19 and keeping themselves and our growers safe — setting traps, changing lures, servicing traps, and identifying SWD. Plus, dealing with gentle reminders to enter data online or send in first trap catch info so that you, our readers, were kept informed via the blogs and distribution map. Thank you SWD first years!

  • Ariel Kirk, Steuben County CCE
  • Barb Neal, Tioga County CCE
  • Grace Marshall, NYS IPM Program
  • Janet van Zoeren, Lake Ontario Fruit Program
  • Liz Alexander, Chemung County CCE
  • Lydia Brown, Hudson Valley Research Laboratory
  • Sarah Tobin, Eastern NY Commercial Horticulture Program

Regular contributors

These Cornell scientists have been the foundation of our monitoring network! This network would not be possible without their support and contributions — suggestions for improvement, ideas for mapping, perspectives on grower needs and steadfast cooperation. Yes, they've done the trapping and dealt with the gentle reminders and they're still with the program. Thank you SWD trappers!

  • Andy Galimberti, Eastern NY Commercial Hort Program
  • Dave Thorp, Livingston County CCE
  • Don Gasiewicz, Wyoming County CCE
  • Elisabeth Hodgdon, Eastern NY Commercial Hort Program
  • Faruque Zaman, Suffolk County CCE
  • Jim O'Connell, Ulster County CCE
  • Liz Tee, Lake Ontario Fruit Program
  • Natasha Field, Eastern NY Commercial Hort Program
  • Peter Jentsch, Hudson Valley Research Laboratory
  • Sharon Bachman, Erie County CCE

Special thanks go to Laura McDermott!

A picture of Laura McDermott, Extension Educator, hosting a field workshop on SWD.
Laura McDermott, Extension Educator, CCE ENYCHP, gives a talk on SWD at a field workshop featuring hummingbirds in raspberries.

Laura McDermott, Eastern NY Commercial Horticulture Program (ENYCHP), has gone above and beyond to support the SWD monitoring network from its inception in 2013 by building a strong collaboration in Eastern NY with a goal of having a trapping location in every county in the ENYCHP. This year, 9 of 17 counties in ENYCHP participated in SWD monitoring. I know Laura would say she couldn't do this without the willing collaboration of her colleagues in the ENYCHP, in Ulster County CCE, and in the Hudson Valley Research Lab. But, we know that without her efforts in bringing us all together, SWD monitoring in Eastern NY wouldn't be as comprehensive as it is. Thank you Laura!

Photograph of Commissioner Richard Ball.“Our office has received questions from a few New Yorkers who have received unsolicited packages allegedly sent from China that are marked as containing jewelry (or other items) but which actually contain plant seeds. Similar packages have been received in other states and the United States Department of Agriculture is investigating. People who receive seeds should not plant or handle the seeds. They should store them safely in a place children and pets cannot access and email USDA immediately at for instructions. Seeds imported into the United States are rigorously tested to ensure quality and prevent introduction of invasive species, insects and diseases. We will continue to monitor this issue and will pass along guidance as it is received from USDA.” – Statement from Richard A. Ball, New York State Commissioner of Agriculture

The above statement from Commissioner Ball comes as the number of mysterious packages, which have been received by people across the country for a while now, has increased recently.

To date, we don’t know what kind of seeds they are of if they might be carrying some kind of plant pathogen. The recommendation from the USDA’s Animal and Plant Health Inspection Service (APHIS) is to immediately email the USDA and hold onto the seeds and packaging, including the mailing label, until someone from your State department of agriculture or APHIS contacts you with further instructions. Do not plant seeds from unknown origins.

APHIS ends their press release on the subject with “USDA is committed to preventing the unlawful entry of prohibited seeds and protecting U.S. agriculture from invasive pests and noxious weeds. Visit the APHIS website to learn more about USDA’s efforts to stop agricultural smuggling and promote trade compliance.”.

At the NYS IPM Program, research, demonstrations, education, and outreach are part of a comprehensive plan to make IPM the safe, effective pest management solution for all New Yorkers. For more information about our efforts to combat invasive species, visit our Invasives Species page. For updates on this, and other pest related subjects, follow us on FacebookTwitter, and Instagram.

This post contributed by Joellen Lampman, School and Turfgrass IPM Extension Support Specialist, NYS IPM Program. See her post on the NYS IPM blog,

Please learn more about summer insect management in cherry orchards by listening to the recorded webinar about managing SWD and Rhagoletis fruit flies in cherries. Learn how to protect your cherry harvests.

A trap to monitor SWD set in a tart cherry tree.
SWD trap set in a tart cherry tree.

As SWD has now been trapped in most locations across the state, and fruit begins to blush, it’s time to be sure to keep a tight control schedule in any orchard with SWD pressure.

This webinar was organized by LOF and NYS IPM and sponsored by Valent and FMC.

We discuss the best management tactics to combine control for SWD and Rhagoletis fruit flies in cherry and other crops.


12:00 - Intro, sponsorship, SWD biology basics – Janet van Zoeren, Lake Ontario Fruit Program

12:10 - SWD management in tart cherry – Julie Carroll, NYS IPM Program

12:25 - Managing cherry fruit fly, black cherry fruit fly, and European cherry fruit fly – Art Agnello, Department of Entomology

12:45 - Questions and answers

Timing of talks will be relatively flexible and fluid, but we'll make sure to leave plenty of time for Q and A.

This event was free, but pre-registration was required. If you missed it, you can now listen to the webinar as if you were there!

Organized by Lake Ontario Fruit program and NYS IPM. Proudly sponsored by FMC and Valent USA.

Any questions or concerns please contact Janet van Zoeren,, IPM Specialist, CCE Lake Ontario Fruit Program.

This post was contributed by Janet van Zoeren,, IPM Specialist, CCE Lake Ontario Fruit Program.

Juneteenth, what a great day! I first learned of Juneteenth when I bought a calendar and Juneteenth was listed on June 19th.  I think this was just last year. I'll never forget it now, nor should you. I quote here from the post What Is Juneteenth?
by Henry Louis Gates, Jr. (Originally posted on The Root). The order Maj. Gen. Gordon Granger issued, in establishing the Union Army’s authority over the people of Texas:

The First Juneteenth
“The people of Texas are informed that, in accordance with a proclamation from the Executive of the United States, all slaves are free. This involves an absolute equality of personal rights and rights of property between former masters and slaves, and the connection heretofore existing between them becomes that between employer and hired labor. The freedmen are advised to remain quietly at their present homes and work for wages. They are informed that they will not be allowed to collect at military posts and that they will not be supported in idleness either there or elsewhere.” —General Orders, Number 3; Headquarters District of Texas, Galveston, June 19, 1865

I encourage you to read the entire What is Juneteenth? post and perhaps kindle a keen interest in Civil War history and the history of black people in the United States. We must end slavery in our hearts and embrace freedom for all. Cornell University President Martha Pollock brought this post to our attention. Juneteenth is now an official holiday for all Cornell University.

I was born in Little Rock, Arkansas. The day I was born, riots broke out in the city over school desegregation. My mother made note of it in my baby book. White people yelled at the black children, teenagers, who were going to school with their white children for the first time. The yelling, angry white people lined the streets around where the black children walked to school. The police protected those black students then, from those unruly white adults. To protect and to serve. We must relearn and revisit our priorities. Black Lives Matter.

What is it like to live with fear of police brutality, racial profiling, and random acts of unkindness? What is it like to have those fears realized? Within my lifetime, I want to make these questions obsolete, the need to ask them irrelevant, and their answers a distant memory that fades from view, serving only to remind us of the better world we live in where such questions don't need to exist nor even come to mind.

I share the New York State IPM Program statement with you —

Our Statement
As a statewide program focused on reduced risk in agricultural and community settings, we are honored to work with diverse stakeholders across NY and pledge to do more to support our CCE Director’s desire to improve and foster a culture of inclusion.

I share the CCE Director's statement with you —

 Dear Cornell Cooperative Extension Community,

Like so many of you, I am devastated by racist violence and senseless killing of Black men and women, including those that we have heard about in recent weeks: George Floyd, Ahmaud Arbery, and Breonna Taylor. We firmly denounce the ways in which structural racism and white supremacy disproportionately and detrimentally impact the lives of Black members of our community. We also recognize the resulting racialized trauma that stifles dreams, smothers hope, and compromises our shared humanity across race.

Cornell Cooperative Extension’s strong ties in diverse communities across New York State compels us to fully embody the principles of equity and inclusion in our programs, in our interactions with community members, and with each other. To this end, CCE pledges to foster a culture of belonging in our communities where all are supported and welcome to pursue their dreams and opportunities for growth without fear or apprehension.

We invite all members of the extension community to join our collective efforts to transform ourselves, our relationships, and our systems through critical self-reflection, courageous conversations, and bold actions. Our intentional efforts in doing so will lead us to a more just, healed, and thriving community for all.


Christopher B. Watkins
Director, Cornell Cooperative Extension

Enjoy Juneteenth! Let's take steps towards a more just, healed, and thriving community for all.

Overall, still a quiet week for SWD trap captures in the Lake Ontario region's tart cherries. Although SWD was caught across the region, only 2 at most in the two traps set per orchard. Traps were checked Monday and Tuesday, June 15 and 16. Elizabeth Tee and Janet van Zoeren, Lake Ontario Fruit Program, and Grace Marshall and Juliet Carroll, NYS IPM Program, are participating in this study along with nine fruit growers.

In our 11 study orchards, SWD has been caught in 5 of the 6 “lake” blocks and in 3 of the 5 “inland” blocks. Specific trap catch results for this week were:

  • Zero SWD in six orchards out of 11.
  • First catch in one orchard = 1 female in edge trap.
  • Recatch in three orchards = 1 male in edge trap; 2 females in edge trap; 1 male & 1 female in interior trap. Each orchard had one week with zero SWD between first catch and this week’s catch.
  • Sustained catch in one orchard = 1 male in interior trap this week and 1 male in edge trap last week.

SWD populations were still low over the past week in tart cherry orchards. What can we credit with keeping SWD populations low, so far? Some possibilities include:

  • Choosing insecticides that are also effective against SWD for other key cherry insect pests such as plum curculio or the Rhagoletis fruit flies (cherry fruit fly, black cherry fruit fly, European cherry fruit fly).
  • The dry weather and low humidity.
  • Lack of alternate fruit resources in the wild, due to freeze events.
  • Slow progression of fruit development, due to the cold spring.
  • Possibly the cold weather last week and cold nights lately.

Populations are low in berries, too, in western NY. This past week, SWD was only caught in one of the 12 berry sites in the Lake Ontario, Finger Lakes, and Central NY regions that we are monitoring.

Cherry fruit is starting to color.

Be watchful of your crop's development. Now is the time to plan your SWD management strategy so you have a good selection of rotational insecticides to protect your crop through to harvest.

Picture of Juliet Carroll, NYS IPM Program, servicing an SWD trap hung in a tart cherry tree.
Juliet Carroll checks a SWD trap in a tart cherry orchard to help determine the need to spray, as fruit ripen.

For cherry fruit fly management (Rhagoletis spp.), choose insecticides that also have activity against SWD to keep the population down and protect your fruit from Rhagoletis fruit flies. Refer to the SWD Insecticide Quick Guide for tree fruit and grapes Cross-reference this with the Cornell Pest Management Guidelines for Commercial Tree Fruit Production. Select insecticides wisely. 

SWD can lay eggs in ripening cherries. If SWD has been caught in your orchard, ripening and ripe cherries will be at risk of SWD infestation. Pay close attention to preharvest intervals (PHI) and plan insecticide use so you have materials with lower PHI for use close to harvest. Rotate IRAC groups for resistance management. Drosophilids are known to develop insecticide resistance. Follow label directions. Be wise.

SWD management tactics

  • Mowing – to reduce humidity and niches for SWD harborage and to increase sun penetration. Research has shown this works in tart cherry orchards in Michigan.
  • Weed management – to reduce humidity, alternate fruiting hosts and harborage and to increase sun penetration.
  • Pruning – to reduce humidity and to increase sun and spray penetration. Research has shown this works in tart cherry orchards in Michigan. Improve your pruning strategy this winter.
  • Monitoring – to know if SWD is present when fruit is ripening. Don't spray unless SWD is caught. Some years your crop may not need a targeted program for SWD.
  • Sanitation – to reduce reproduction harborage and overall SWD population. Important in diversified fruit farms.
  • Cold storage – to slow or kill any eggs and larvae in harvested fruit. Not applicable for a processing crop harvested into water tanks. SWD won't survive in water tanks; larvae may float to the surface or fruit may float higher because the infestation changes their buoyancy.

Bookmark online resources

On Wednesday, May 13, 2020, Jim O'Connell, Ulster County CCE, will be hosting a webinar on that new spotted invasive, spotted lanternfly (Lycorma delicatula). This insect threatens vineyards, woodlands and orchards...and backyards! It has caused significant damage to wine grapes in Pennsylvania, where it was first introduced from Asia.

Picture of the fourth-instar nymph of spotted lanternfly.
Fourth instar of spotted lanternfly, before the adult stage.

Fascinating insects, Fulgorids. Yet, none existed in North America...until now! Learn more about these up-and-coming pests, how to identify them and how to report any sightings of them. Help us keep the populations of spotted lanternfly (SLF) under control and, preferably, out of New York State. (I used to love polka dots, now I'm not so sure.)

Attend the Online Spotted Lanternfly Workshop on Wednesday, May 13, 2020, from 9:30 AM - 12:00 PM.

Register here Register in advance for this meeting:

After registering, you will receive a confirmation email with information about joining the meeting.

This SLF meeting will update farmers and the general public about this new invasive species that has the potential to cause severe economic injury to many important crops in Ulster County and New York State.

Spotted lanternfly (SLF) is originally from China and parts of Southeast Asia. It was first detected in Pennsylvania in September of 2014 and a state quarantine of 13 counties was enacted. Since then, it has spread to adjacent counties, as well as parts of New Jersey, Maryland, Delaware, Virginia, and West Virginia.

Picture of an adult spotted lanternfly on a tree trunk
Spotted lanternfly adult on the trunk or a tree.

At this workshop, learn about:

  • the biology of SLF,
  • it’s preferred hosts,
  • economic injury sustained in Pennsylvania,
  • how to report sightings,
  • and regulatory restrictions in place to limit the spread of SLF.

These insects are over an inch long!

There is no cost to attend this meeting, however, pre-registration is required.

Register here and receive your confirmation email with the link to join the workshop.

2.25 NY DEC Pesticide Credits have been approved for this meeting in categories 1A, 2, 3A, 9, 10, 22, 25. Those seeking credits must attend all sessions and actively participate. Learn more about SLF, attend the Online Spotted Lanternfly Workshop! May 13, 9:30 - noon.

Content for this post was contributed by James O’Connell, Senior Ag. Resource Educator, Cornell Cooperative Extension, Ulster County,

Are they in New York State? Yes!  Where are they?  We're going to find out! A statewide weed herbicide resistance screening project will start this year. Dr. Lynn Sosnoskie, specialty crop weed science, Dr. Bryan Brown, IPM weed management specialist, and Dr. Toni DiTommaso, soil and crop sciences, will find out. Help them to help you!

Weeds compete with crops for light, water, and nutrients, which can result in yield reductions. Weeds can also interfere with crop production by serving as alternate hosts for pests and pathogens, providing habitat for rodents, and impeding harvest operations. Consequently, growers employ a variety of control strategies, including the application of herbicides, to manage unwanted vegetation. Although herbicides can be extremely effective at controlling undesirable plants, failures can and do occur. Weeds may escape chemical treatments for many reasons including the evolution of herbicide resistance.

Worldwide, there are 512 confirmed cases (species x site of action) of herbicide resistance. With respect to the United States, 165 unique instances of resistance have been documented.

A chart showing the status of herbicide resistance cases globally from 1950 to 2020.
Current status of herbicide resistance, globally, over time according to the International Survey of Herbicide Resistant Weeds (

In New York, only four herbicide resistance occurrences have been formally reported:

  • common lambsquarters (Chenopodium album)
  • smooth pigweed (Amaranthus hybridus)
  • common ragweed (Ambrosia artemisiifolia)
  • common groundsel (Senecio vulgaris)
  • All described as insensitive to photosystem II inhibitors (e.g. atrazine and simazine).

This, however, does not reflect the current on-the-ground situation in the state. Work done by Drs. Julie Kikkert (CCE) and Robin Bellinder (Cornell) indicates resistance to linuron in some populations of Powell amaranth (Amaranthus powelli). Recent studies by Drs. Bryan Brown (NYS IPM) and Antonio DiTommaso (Cornell) suggest that horseweed (Conyza canadensis) and waterhemp (Amaranthus tuberculatus) populations may be resistant to one or more herbicide active ingredients.

Pennsylvania has nine reported cases of herbicide resistance including glyphosate resistance in Palmer amaranth (Amaranthus palmeri), which was recently identified here in NY. While it is tempting to believe that herbicide resistance is a hallmark of agronomic cropping systems, herbicide resistance can and has developed in orchards, vineyards, vegetable crops, pastures, and along roadsides.

Photo of two horseweed seedlings.
Horseweed (Conyza canadensis) seedlings.  Photo: L. Sosnoskie

Beginning in 2020, we will undertake a screening effort to describe the distribution of herbicide resistance in the state.

You can be a part of this important work. This coming summer and fall, growers, crop consultants and allied industry personnel who suspect they have herbicide resistance are encouraged to contact Dr. Lynn Sosnoskie (, 315-787-2231) to arrange for weed seed collection.

Indicators of suspect herbicide resistance:

  • Dead weeds intermixed with live plants of the same species.
  • A weed patch that occurs in the same place and continues to expand, yearly.
  • A field where many weed species are controlled but a previously susceptible species is not.
  • Reduced weed control that cannot be explained by skips, nozzle clogs, weather events, herbicide rate or adjuvant selection, and calibration or application issues.

Growers can take several actions to stop the spread of herbicide resistant weeds and to prevent the development of new ones.

  1. First and foremost is scouting fields following herbicide applications and keeping careful records of herbicide performance to quickly identify weed control failure.
  2. Pesticide applicators should ensure that their equipment is properly calibrated and that they are applying effective herbicides at appropriate rates to manage the target species.
  3. Whenever possible, diversify herbicides to reduce chemical selection pressures that result from the repeated use of a single herbicide or site of action.
  4. If possible, incorporate physical and cultural weed control practices into a vegetation management plan.
  5. Be sure to control unwanted plants when they are small and never allow escapes to set seed.
  6. Clean equipment to prevent seeds of herbicide-resistant weed species from moving between infested and non-infested sites and harvest areas with suspected resistant populations last.

Juliet Carroll, your friendly SWD blogger, says, "It's that time of year, you've put on your pre-emergent and post-emergent herbicides in the rows or between the rows, and you're keeping an eye on things to make sure those weeds are dying or not emerging. Continue your vigilance, flag suspects, and contact the "Super Weed Team" to collect suspect seeds to help them help you fight herbicide resistance."

This article was contributed by Lynn Sosnoskie,, Horticulture, Cornell AgriTech.


Esther Kibbe, Western NY Berry Specialist, has started a newsletter on the Cornell Fruit Resources Berry Blog, You can easily subscribe to this blog and get updates on field observations from Western NY. Or contact Esther via email at

Her April 6 Scouting Update - Western NY has great photos and a summary of her findings. Take a look:

A screen shot showing the subscribe area of the Berry Blog page.
At the bottom of the right hand sidebar on a desk top or at the bottom of the blog page on a smart phone, you'll find the place to subscribe.

Esther will be visiting fields and sharing her findings with you. She'll also be in touch with Cornell Cooperative Extension educators who work in berries and berry growers. This way, even in these uncertain times, she can share everyone's findings via this blog.

Laura McDermott, Eastern NY Commercial Horticulture Program, is thrilled to see the evolution of statewide coverage of berry field reports during this difficult time when we are facing a limited ability of Cornell Cooperative Extension staff to conduct farm visits in response to grower's needs.

So, subscribe to the Berry Blog today!

And don't worry. I'll still be posting SWD updates and other cool stuff, as usual, here on the SWD blog! Have a fantastic growing season.

Skip to toolbar