Stop the Rot! - Using Cultural Practices to Manage Bacterial Diseases of Onion
Christy Hoepting, Extension Vegetable Specialist
Cornell Vegetable Program
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.
Stop the Rot article (pdf; 1356KB)
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Upcoming Events
Chautauqua Winter Vegetable Meeting
February 10, 2023
Clymer, NY
Meeting will feature growers from Ohio sharing their production know-how and thoughts on food safety. Other topics include weed control, pesticide safety, and the impact of poor crop nutrition. 0.75 DEC credits in 1a, 23 plus 0.5 in CORE, which is good for all categories. Trade show booths available.
Meeting cost is $20/person, includes snacks and educational materials. Registration required by 4 pm on Friday, February 3.
Orleans Regional Vegetable Meeting
February 15, 2023
Albion, NY
Offering presentations in pesticide safety, tips for managing diseases in vegetable crops, how to attract beneficial insects to your field, herbicide options for cole crops, and strawberry disease information. Meeting cost is $10 per person, payable at the door via cash or check. Pre-registration requested by 5:00 pm on Monday, February 13.
DEC credits available: 2.25 in 1a and 10; 2.0 in 23; 1.5 in 22; and 0.5 in CORE (used in all categories)!!
NYS Processing Vegetable Industry Roundtable Meeting
March 15, 2023 : Morning Session: Snap Beans, Sweet Corn, and Peas
Batavia, NY
Processing vegetable industry members who grow, manage, or support snap bean, sweet corn, or pea production for Nortera and/or Seneca Foods, should attend this session of the roundtable meeting. You will:
- Network at this in-person meeting.
- Learn the results of industry-funded research.
- Have a voice in Cornell research and extension.
- Earn 2.0 DEC credits in categories 1a, 10, 23 and CCA recertification credits.
This FREE event is followed by lunch! Pre-registration requested.
March 15, 2023 : Lunch Break and Networking
Lunch is FREE to anyone attending either the Morning Session or the Afternoon Session of the NYS Processing Vegetable Industry Roundtable Meeting. Registration is required.
March 15, 2023 : Afternoon Session: Beets and Carrots
Batavia, NY
Processing vegetable industry members who grow, manage, or support beet or carrot production for Nortera, Seneca Foods and/or Love Beets, should attend this session of the roundtable meeting. You will:
- Network at this in-person meeting.
- Learn the results of industry-funded research.
- Have a voice in Cornell research and extension.
- Earn 2.0 DEC credits in categories 1a, 10, 23 and CCA recertification credits.
Lunch is provided before this session. It's FREE! Pre-registration requested.