Onions
Onions are one of the most important vegetable crops in New York State with annual sales of approximately $52 million. New York accounts for 97% of the onion production in the North Eastern United States and ranks sixth in the nation. Approximately 12,000 acres of yellow pungent cooking onions are grown from direct seed, predominantly on organically rich muck soils. This crop is stored and marketed until April. Sweet and red varieties are also grown, mostly from transplants. Hundreds of small-scale diversified farms grow onions intensively on plastic beds on less than an acre. These onions can grow very large and be lucrative in the market place where they are sold through produce auctions, farmer's markets, roadside stands and CSAs.Continued intensive production of onions in New York has led to an array of perennial pest challenges, as well as the introduction of new pests, so that management of the onion complex in New York requires a very strategic research-based approach. Cornell Cooperative Educators and Cornell faculty work together to conduct research on many aspects of onion production in the state. Below you will find educational information and results of our research trials.
Relevant Events
2026 Cornell Winter Fruit Webinar Series
January 22, 2026 : Blueberry Pruning and Soil Health to Minimize Pests and Maximize Yield
January 29, 2026 : Cost of Production for Fruit Crops
February 12, 2026 : Fire Blight Management Updates
February 19, 2026 : Pink and Petal Fall Insecticides- Can We Strike the Right Balance?
March 12, 2026 : Inoculating Orchards with Mycorrhizal Fungi
March 19, 2026 : St. Peachtrick's Day - Cherry Pruning Strategies and Plum Varieties for the Northeast
2026 Northeast Extension Fruit Consortium Winter Webinar Series
February 4, 2026 : Management of Up and Coming Strawberry Diseases in the Northeastern United States
February 11, 2026 : Kiwiberry Production in the Northeast
February 18, 2026 : Heat Mitigation- Sunburn and Fruit Coloring
February 18, 2026 : The Dating Game- Updates in Lepidopteran Mating Disruption
March 4, 2026 : USEPA Endangered Species Act Strategies and Pesticide Use
March 11, 2026 : Practical Drought Management for Fruit Growers
Tree Fruit Scouting - Online Course
February 25, 2026 : Tree Fruit Scouting - Online Course
Reminder on Calculating Fertigation Rates for Plastic Mulches
Chuck Bornt, Team Leader, Extension Vegetable Specialist
Eastern New York Commercial Horticulture
2021 Storage Onion Variety Trial
Crystal Stewart-Courtens, Extension Vegetable Specialist
Eastern New York Commercial Horticulture
2021 Guidelines for Onion Thrips Management
Ethan Grundberg, Vegetable Specialist
Eastern New York Commercial Horticulture
Assessing Biocontrols for Pink Root Mitigation and Yield Impact in Onions
Ethan Grundberg, Vegetable Specialist
Eastern New York Commercial Horticulture
Thanks to the generous support of the members of the New York Onion Research and Development Program (ORDP) board, Ethan Grundberg and Amara Dunn began evaluating commercially available plant growth regulators, biostimulants, and biofungicides for potential suppression of pink root and impact on yield in transplanted bare root 'Highlander' onions during the 2018 growing season. As discussed in the proposal for "Assessing Biocontrols for Pink Root Mitigation and Yield Impact in Onions", few conventional fungicides are labeled for pink root management in New York and even fewer are labeled for use as pre-plant dips for bare root transplanted onions. The goal for the first year of research on this project was to screen a large number of what were broadly designed as biological products, many of which are already being used by onion growers, in order to narrow the focus of future research efforts to find solutions for managing pink root in transplanted onions.
Onion Thrips Management Recommendations for 2018
Ethan Grundberg, Vegetable Specialist
Eastern New York Commercial Horticulture
Onion thrips populations have exceeded action thresholds in a few hot spots in Orange County. Review Dr. Brian Nault's insecticide recommendations for onion thrips management that incorporate newly registered products in New York State.
Allium Leafminer Spring Flight Update
Ethan Grundberg, Vegetable Specialist
Eastern New York Commercial Horticulture
The spring flight of the new invasive insect pest, the allium leafminer, is coming to an end. However, the larval stage of the pest will remain active for a couple of more weeks and can cause significant damage to garlic, scallions, onions, and chives. Read more about how to continue to protect your spring allium crops and how to prepare for the fall flight.
Lookout for Leek Moth
Amy Ivy, Vegetable Specialist
Eastern New York Commercial Horticulture
Leek moth adults emerge in mid April to mate and lay eggs. This year the first moths were caught in Essex on April 21. The larvae will hatch in a couple of weeks and can do considerable damage to garlic scapes so this is a good first place to look when scouting.
Be cautious when buying and selling onion transplants between growers in the infested areas. We have seen leek moth appear in new locations when infested plants were brought in from farms to the north.
Responding to Hailstorms 2018
Crystal Stewart-Courtens, Extension Vegetable Specialist
Eastern New York Commercial Horticulture
The fierce storm that hit much of the Eastern New York region south of Albany on Wednesday, May 15, 2018 caused tremendous wind, water, and hail damage. For growers wondering how to respond to hail damage to young plants, read more about how to best protect your crops.
Allium Leafminer Spring Flight Has Begun
Ethan Grundberg, Vegetable Specialist
Eastern New York Commercial Horticulture
The new invasive insect pest, the allium leafminer, has begun its spring flight. Adults are expected to be active for about four weeks; see what management options are available to reduce damage to your allium crops.
Be on the Lookout for Southern Blight
Ethan Grundberg, Vegetable Specialist
Eastern New York Commercial Horticulture
Southern Blight (Sclerotium rolfsii) was found on golden storage beets this winter in Dutchess County. The fungal pathogen is fairly new to New York and poses a threat to a wide range of vegetable crops. Early detection and proper diagnosis are key to managing this disease.
Allium Leafminer Active in Southern Pennsylvania
Teresa Rusinek, Vegetable Specialist
Eastern New York Commercial Horticulture
A new invasive insect pest in the Northeast known as the Allium leafminer (ALM), Phytomyza gymnostoma, damages crops in the Allium genus (e.g., onion, garlic, leek, scallions, shallots, and chives) and is considered a major economic threat to Allium growers. Originally from Europe, ALM was first detected in Lancaster County, Pennsylvania in December of 2015 and in New Jersey and New York in 2016. As of fall 2017, ALM activity has been confirmed throughout eastern Pennsylvania, New Jersey, Delaware, southeastern New York as well as Thompkins and Suffolk counties.
Onion and Seed Corn Maggot Concerns in a Cold, Wet Spring
Crystal Stewart-Courtens, Extension Vegetable Specialist
Eastern New York Commercial Horticulture
Last year we saw a lot of problems with root feeding damage from maggots early in the season, which has growers on edge about pest pressure this year. Seed corn maggots can damage a variety of crops, and in previous years have been observed on everything from sunflower shoots in the greenhouse to pea seedlings and onion transplants in the field. Onion maggots are more particular, and will only feed on allium hosts.
2018 Eastern New York Fruit & Vegetable Conference Vegetable Presentations
Presentations from the 2018 ENYCHP Eastern New York Fruit & Vegetable Conference held February 20th and 21st for the vegetable sections.
Growing Alliums for Storage & Long Term Sales Resource Guide
Pink Root on Your Onion Transplants: To Plant or Not to Plant?
Anne Mills, Field Technician
Eastern New York Commercial Horticulture
Word on the Black Dirt in Orange County is that many growers are receiving Arizona-grown onion plants that are heavily infected with pink root.
Responding to Hailstorms
Crystal Stewart-Courtens, Extension Vegetable Specialist
Eastern New York Commercial Horticulture
While no one wants to think about the possibility of hail hitting their beautiful crops just as they start to respond to the heat and take off, the likelihood that we will see more hail seems pretty high. So let's talk about it.
Exploring the Relationship Between Nitrogen, Plant Spacing and Bacterial Disease
Christy Hoepting, Extension Vegetable Specialist
Cornell Vegetable Program
It is important to emphasize that "exploring" is in the present tense. In New York, we are just beginning to delve into the fascinating relationship between nitrogen, plant spacing and bacterial diseases of onions. Our preliminary results suggest that reduced soil nitrogen and tighter plant spacing results in less bacterial decay. In this article, we report preliminary findings from exploratory studies and the observations that lead to these trials. We stress that we are not making recommendations at this time. However, we are hopeful that further studies will lead to specific recommendations.
Preventing Muck Soil Erosion by Reducing Tillage in Onion Production
Christy Hoepting, Extension Vegetable Specialist
Cornell Vegetable Program
The problem with using conventional tillage practices for onion production on muck soils is that it results in the subsidence of muck via wind and water erosion and oxidation of organic matter at a rate of one foot every 10 years, which is not sustainable for preserving these non-renewable natural resources for long-term productivity. Onions are one of the most valuable vegetable crops produced in New York State with the majority of the 13,000 acres being grown on muck soil. Producing onions using conventional tillage practices results in degradation of soil health and increased subsidence.
O-zone Injury on Vegetables
Crystal Stewart-Courtens, Extension Vegetable Specialist
Eastern New York Commercial Horticulture
Hot, humid weather with stagnant air masses may lead to ozone damage on crops. Ozone warnings were recently issued for much of New York. These warnings are intended for people with respiratory problems and let them know they should limit their outdoor activity and try to stay as much as possible in air-conditioned locations. These warning are also a good indicator that ozone damage may occur in plants.
Leek Moth Control and Information
Christy Hoepting, Extension Vegetable Specialist
Cornell Vegetable Program
Leek Moth was detected in four home gardens in Plattsburg, NY in 2009. It was first detected in Ontario, Canada in 1997 where it has become problematic especially to small-scale, organic growers in eastern Ontario and to commercial producers in western Quebec, who have limited insecticides available to them.
Leek Moth continues its spread to more farms and gardens across the U.S., a new comprehensive website is available to aid in the identification and management of this pest. This Cornell website features maps of the distribution of leek moth, protocols on insect monitoring and identification, best management practices for farms and home gardens, a photo gallery of damage symptoms and a comprehensive resource section.
Visit the Leek Moth website.
Stop the Rot! - Using Cultural Practices to Manage Bacterial Diseases of Onion
Christy Hoepting, Extension Vegetable Specialist
Cornell Vegetable Program
Narrow plant spacing reduced bacterial bulb decay by 53 to 64%
Do you know how easy this is? A simple modification to adjust your planting configuration is all it would take to drastically reduce losses from bacterial bulb decay. Our studies showed that when plant spacing was reduced from 6 or 8 inches to 4 inches with 3 or 4 rows per 3-foot plastic mulch bed (row spacing: 4 rows = 6 inch; 3 rows = 8 inch), this provided 53 to 64% control of bacterial bulb decay at harvest (Table 1). Marketable yield also increased by 1.4 to 2.4 times, representing an increased net economic return of $43 to $258 per 100 feet of bed, due to increased weight of marketable jumbo-sized bulbs (Table 1). We learned that wide plant spacing produces big bushy plants with more leaves, thicker necks, delayed maturity and bigger bulbs. Unfortunately, it was these bigger bulbs that rotted! By narrowing plant spacing, we got fewer colossal-sized bulbs, which we more than made up for by having significantly more healthy jumbo-sized bulbs to market (Table 1).
Alternatives to black plastic reduced bacterial bulb decay by 59 to 75%
This is also a very simple and easy modification for small-scale growers producing onions on plastic mulch to make to their cultural practices that could go a very long way towards reducing bacterial bulb decay. Our studies showed that reflective silver mulch, biodegradable black plastic and bare ground had significantly 1.8 to 2.8 times higher marketable yield than black plastic (Table 2). Reflective silver and biodegradable black plastics had significantly 3.7 and 3.6 times, respectively, higher jumbo weight than black plastic, which resulted in an increased net return of $96 to $215 per 100 feet of bed compared to black plastic (Table 2). All of the alternatives to black plastic had significantly lower soil temperatures compared to the black plastic; we suspect that the higher temperatures of the black plastic are more favorable for development of bacterial diseases.
Fall Application of Dual Magnum for Yellow Nutsedge Control in Muck Onions
Christy Hoepting, Extension Vegetable Specialist
Cornell Vegetable Program
Yellow nutsedge (Cyperus esculentus L.) pressure is very high in certain muck areas where onions are grown. It appears to have become more of a problem in recent years. Onion growers and chemical company representatives believe that applying Dual Magnum, active ingredient metalochlor, in the fall can significantly reduce nutsedge pressure the following spring. However, weed scientists across the country do not believe that fall applications of metalochlor would have any effect on nutsedge populations the following spring, because the dissipation of metolachlor, is relatively rapid, 4-7 weeks in the northern United States. Dual Magnum is labeled as a fall application in field corn and soybeans only in Iowa, Minnesota, Minnesota, North Dakota, South Dakota and Wisconsin. For this use, there are restrictions on the label that state the date after which Dual Magnum may be applied, that soil temperature in the top 4 inches must consistently be 55°F and lower, and that tillage following incorporation must not exceed the 2-3 inch depth of incorporation.
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Upcoming Events
Pesticide Applicator Certification Exam Prep Course
January 13 - January 14, 2026
Join ENYCHP specialists for an in-depth review of topics covered on the NYS DEC pesticide applicator certification exam. This two-day virtual course includes explanation of key concepts on the core exam, test-taking tips for the core and category exam, practice questions, and Q&A with instructors. Course materials, including program recordings, practice exams, and DEC materials will be available to registrants after the program. This training is geared toward certification categories 1A (agricultural plant), 21 (field and forage), 22 (fruit), and 23 (vegetable).
I thought I was covered for that! Farm Insurance Webinar Series, Jan-Feb 2026
January 13, 2026 : Session 1: Insurance and Risk Management 101
Insurance and Risk Management 101. This first webinar will cover many of the general provisions found in insurance policies and describe some of the terms to be aware of when you are considering your options. Steve Hadcock, Capital District Hort Team and Greg Murk, FarmNet.
January 20, 2026 : Session 2: Liability Insurance
Coverage for the risk that your business will cause harm to someone. Are you having people on your farm or selling a food product? You might need liability insurance. Robert Hadad, Cornell Vegetable Program, Elizabeth Higgins, Eastern NY Commercial Hort Program.
January 27, 2026 : Session 3:Protecting Yourself from Disasters (Crop Insurance, USDA FSA programs and Flood Insurance)
Are you protected from a weather event on your farm? Learn about your options for Disaster Coverage (crop insurance, FSA programs, flood insurance). Elizabeth Higgins, Eastern NY Commercial Hort Program.
February 3, 2026 : Session 4: Insuring People (health, life and disability insurance)
Options for health insurance, life insurance and disability insurance, and how they can help farmers and their employees. Maire Ullrich, CCE Orange County and Lucas Smith, Cornell Ag Workforce Development
February 10, 2026 : Session 5: Property Insurance
Insuring your infrastructure, equipment, and livestock from loss. Learn about the types of coverage, and the risks they reduce. Colin Hostetter, Tri-County Ag Team, Desiree Keever, CCE Delaware County and Steve Glick, Kevin Daniels Agency.
2026 Becker Forum - Save the Date
January 14, 2026 : Save the Date - 2026 Becker Forum
Geneva, NY
The Becker Forum, an annual gathering of growers, farm managers, and industry experts, offers a comprehensive program tailored to address the most pressing challenges facing the agricultural community today. The day will feature a series of informative sessions designed to equip attendees with the tools and knowledge they need to navigate these complex issues successfully.