Stemphylium was first identified in Ontario in 2008 and has since spread throughout the Holland Marsh and other onion growing areas in southwestern Ontario.
Stemphylium leaf blight can sometimes be misdiagnosed as purple blotch (Alternaria porri), as they both have very similar symptoms initially. Purple blotch has sunken tan to white lesions with purple centers while Stemphylium tends to have tan lesions without the purple centers.
Stemphylium spores are dispersed by wind. Spore sampling at the Muck Crops Research Station using a Burkard seven-day spore sampler detected an average of 33 spores/m3 in 2015 and seven spores/m3 in 2016.
In ideal conditions, leaf spot symptoms occur six days after initial infection. Stemphylium tends to infect dead tissue or wounds, often as a result of herbicide damage, insect feeding or from extreme weather.
Older onion leaves are more susceptible to infection than younger leaves and symptoms are traditionally observed after the plants have reached the three- to four-leaf stage.
Over the last few years, Botrytis leaf blight (Botrytis squamosa) has become less of an issue and has been overtaken by Stemphylium as the most important onion disease — other than maybe downy mildew.
This may be because the fungicides used to target Stemphylium are likely managing Botrytis as well. Since Stemphylium can be so devastating and hard to control, fungicides are now being applied earlier in the season which may be preventing Botrytis to become established.
Botrytis squamosa overwinters as sclerotia in the soil and on crop debris left from the previous year and infects onions in mid-June when temperatures and leaf wetness are favourable for infection. In the Holland Marsh, Stemphylium lesions were first observed on June 29, 2015 and July 7, 2016.
The primary method of management is through foliar fungicides such as Luna Tranquility, Quadris Top and Sercadis. Keep in mind that Sercadis and Luna Tranquility both contain a group 7 fungicide so remember to rotate and do not make sequential applications.
The effectiveness of these fungicides in the future depends on the spray programs you choose today. There are already Stemphylium isolates insensitive to several fungicides in New York so resistance is a real and very serious issue with this disease.
Remember to rotate fungicide groups with different modes of actions to reduce the possibility of resistance. A protective fungicide is best applied when the onion crop has reached the three-leaf stage, however it may not be necessary in dry years.
Research is currently being conducted at the Muck Crops Research Station to improve forecasting models to identify the optimal timing for commercial growers to achieve good control.
BOTCAST disease forecasting model is available in some areas of Ontario to help growers predict the activity of the disease. Warm, wet weather between 18-26°C is most favourable for disease development. Regular field scouting is still the best method to assess disease levels.
Plant spacing that permits better air movement and irrigation schedules that do not extend leaf wetness periods may be helpful in some areas. Recent work at the Muck Crops Research Station has shown that spores increase two to 72 hours after rainfall with eight hours of leaf wetness to be optimal for the pathogen. Irrigate overnight if possible so by morning the leaves can dry out and you don’t prolong that leaf wetness period.
To lower inoculum levels it is crucial to remove or bury cull piles and to bury leaf debris left from the previous year’s crop through deep cultivation. Stemphylium of onion has many hosts including leeks, garlic, asparagus and even European pear.
Take the time to rogue out volunteer onions or other Allium species in other crops nearby and remove unnecessary asparagus or pear trees to lower inoculum levels. As with any other foliar disease of onion, it is beneficial to rotate with non-host crops for three years.
To prevent the development of resistance, it is essential to always rotate between different fungicide groups and/or tank mix with a broad spectrum insecticide. Current products registered for Stemphylium leaf blight of onion are listed by fungicide group below:
Group 7 - Sercadis
Group 7/9 - Luna Tranquility
Group 11/3 - Quadris Top
Where possible, rotate the use of Confine Extra (Group 33) with fungicides that have different modes of actions. Apply at a rate of 7 L/ha in a minimum of 100 L of water/hectare. Use a maximum of 6 foliar applications per growing season. Pre-harvest Interval (PHI) is 1 day.
Confine Extra is currently registered for downy mildew of lettuce, endive, radicchio as well as most brassica crops.
Follow all other precautions and directions for use on the Confine Extra label carefully.
For a copy of the new minor use label visit the PMRA label site: http://pr-rp.hc-sc.gc.ca/ls-re/index-eng.php
Blossom Protect and Botector are now available from Nufarm in Canada, as part of the company’s lineup of herbicides, fungicides and insecticides for Canadian horticultural growers.
“Biological fungicides make up an important and growing part of our fungicide portfolio,” says Maria Dombrowsky, horticultural specialist at Nufarm Agriculture Inc. “Blossom Protect and Botector are great complements to our existing products, and will allow Nufarm to continue to support growers and their IPM programs.”
Blossom Protect is a biological fungicide that provides protection for pome fruit against fire blight (Erwinia amylovora). Botector is a biological fungicide used to protect grapes from botrytis (Botrytis cinerea).
“bio-ferm products contain a unique mode of action that hinders the development of resistance,” says Werner Fischer, managing director with bio-ferm. “Our products are suitable for conventional and organic production, and bring the additional benefit of being safe for humans, animals and beneficials. They are certified through Ecocert Canada.”
Blossom Protect and Botector are available exclusively through Nufarm Agriculture Inc., its distributors and retailer partners across Canada.
Early blight, which is caused by the Alternaria solani fungus, is found in most potato growing regions. Foliar symptoms include small, brown, irregular or circular-shaped lesions that form on the potato plant’s lower leaves later in the season. The disease prefers warm, dry conditions to develop, and can be more severe in plants that are stressed and weakened.
Brown spot, caused by the Alternaria alternata fungus, is closely related to early blight and is found wherever potatoes are grown. Unlike early blight, brown spot can occur at any point during the growing season, producing small, dark brown lesions on the leaf surface.
Aprovia Top fungicide combines two modes of action with preventative and early curative activity on these two key diseases. Difenoconazole (Group 3) is absorbed by the leaf and moves from one side of the leaf to the other to protect both surfaces against disease. Solatenol (Group 7 SDHI) binds tightly to the leaf’s waxy layer and is gradually absorbed into the leaf tissue to provide residual protection.
“After a strong start, a foliar application of Aprovia Top can be used to manage these key diseases and keep potato crops greener longer,” says Eric Phillips, fungicides and insecticides product lead with Syngenta Canada.
Aprovia Top is available now for use in 2017 production. In potatoes, one case will treat up to 40 acres.
At this time, maximum residue limits (MRLs) for Solatenol use on potatoes have been established for markets in Canada and the U.S. Growers should consult with their processor prior to use.
In addition to potatoes, Aprovia Top can be used to control scab and powdery mildew in apples. Aprovia Top also provides control of early blight, powdery mildew, and Septoria leaf spot in fruiting vegetables, as well as powdery mildew, Alternaria blight and leaf spot in cucurbit vegetables.
See the Aprovia Top label for a complete list of crops and diseases.
For more information about Aprovia Top fungicide, please visit Syngenta.ca or the Customer Interaction Centre at 1‑87‑SYNGENTA (1‑877‑964‑3682).
Presidio is now approved for use on ginseng, tobacco, brassica leafy vegetables and greenhouse ornamentals for a variety of troublesome diseases. The PMRA has also approved Presidio for control of pink rot on potatoes.
“These Presidio label additions are really important news for Canadian growers that depend on minor use approvals to protect their high value crops,” says Maria Dombrowsky, horticultural specialist at Nufarm Agriculture Inc. “Now more growers can access Presidio as part of their integrated pest management (IPM) program with a unique class of chemistry for better resistance management.”
Presidio (Group 43) provides growers with preventive and some curative reach-back action against downy mildew and Phytophthora spp., including late blight, on a variety of crops. In addition to these new crops, Presidio is also registered for use on head, stem and root brassica, cucurbits, fruiting vegetables and leafy vegetables.
“Presidio offers a great new option for domestic potato growers managing pink rot,” says Dombrowsky. “Growers should check with their processors before using Presidio on potatoes, because maximum residue limits (MRLs) for potatoes have not been established in all export markets.”
Property 300 SC fungicide is a suspension concentrate fungicide that offers protection against powdery mildew in grapes, cucumbers, pumpkin, squash and melons.
Pyriofenone, the active ingredient in Property, is the newest generation chemical found in the FRAC U8 group. It demonstrates extremely fast translaminar activity that is complemented by a “vapour effect” that is stronger and longer lasting than that of other chemistries found in the same group.
Property is the only group U8 fungicide that can be applied up to the day of harvest on grapes.
Cosavet DF is a dry flowable sulphur fungicide that prevents powdery mildew and controls erinium mite of grape. Its patented formulation ensures a low dust, easy to mix product that helps to minimize the risk of scorching. Cosavet DF also controls a wide variety of diseases in tree fruit, Saskatooon berries, cucumbers and peas.
Variations in particle size ensure immediate, mid-term and residual activity through contact and vapour action to protect against target fungi.
The Plant Management Network (PMN) has released a new presentation entitled Fire Blight and Streptomycin Resistance to help apple growers understand why the resistance has intensified and spread, and to discuss viable management options and new techniques currently under development.
The webcast, developed by Quan Zeng, assistant plant pathologist at the Connecticut Agricultural Experiment Station, covers the biological mechanisms of the Erwinia amylavora pathogen and its history of growing resistance to streptomycin antibiotics. The presentation also discusses management strategies such as:
- Over-winter pruning, copper spraying, and canker treatments
- In-season antibiotic applications, insect control, and other biological controls
- Promising alternate, non-antibiotic management tools and techniques
February 23, 2016, Guelph, Ont – Bayer announces the registration of Luna Tranquility as a foliar fungicide for bulb vegetables, small berries and tomatoes in Canada.
The systemic fungicide is an all-in-one formulation that includes two groups, Group 7 (fluopyram) and Group 9 (pyrimethanil).
“Luna Tranquility is already a valuable fungicide for apple, grape and potato growers and now protects against some of the most concerning diseases for bulb vegetables, small berries and tomatoes,” said Jon Weinmaster, portfolio manager of horticulture for Bayer CropScience Inc. “With both Group 7 and 9 modes of action, this broad spectrum fungicide offers growers excellent disease control resulting in improved yield, quality and post-harvest benefits.”
According to the company, Luna Tranquility is highly plant mobile and shows minimal cross-resistance to other Group 7 fungicides. It also provides post-harvest latent disease protection for soft fruit, with research indicating reduced shrink and decreased fruit deterioration.
The new expansion of the Luna Tranquility label means Canadian growers can now apply this product on:
- Bulb vegetables for protection against botrytis leaf blight, purple blotch and stemphylium leaf blight
- Small berries (including caneberries, bushberries, and low growing berries) for protection against powdery mildew and botrytis gray mould
- Tomatoes for control of early blight and septoria leaf spot
In addition, the Luna Tranquility label is now expanded to include all crops within the pome fruit Crop Group.
For more information regarding Luna Tranquility visit CropScience.Bayer.ca/LunaTranquility.
February 12, 2015, Mississauga, Ont – BASF Canada Inc. (BASF) has been granted a new label expansion for Pristine fungicide for control of bitter rot and black rot in the pome fruit group.
Previously registered for control of scab, powdery mildew, flyspeck, sooty blotch and brooks spot in pome as well as a number of other key diseases in fruit and vegetable crops, Pristine uses both Group 7 and Group 11 active ingredients to provide broad-spectrum disease control.
Pristine also provides growers with the benefits of AgCelence, which may increase growth efficiency and tolerance to minor environmental stress.
For more information about Pristine fungicide, visit www.AgSolutions.ca or contact your retailer.
September 9, 2014, Winnipeg, Man – Makhteshim Agan of North America (MANA) Canada is please to announce the addition of Steve Lepper to their sales team.
Lepper will cover the sales territory encompassing southwest Manitoba and southeast Saskatchewan. He has more than 18 years experience in the crop protection business in western Canada, and is well suited to helping MANA Canada grow their strong market portfolio.
Lepper has worked on both sides of the retail trade, initially on the retail side of the seed business, and as branch manager of a large farm retailer in southern Manitoba. For the last six years, he has worked with a major crop protection company as a territory sales manager and most recently was promoted to key accounts management.
“We are excited to have Steve join the MANA Canada team. His depth of experience in retail sales and the crop protection business brings a unique blend of skills to MANA Canada,” says Andrew Mann, CEO MANA Canada at Winnipeg, Man. “He is a great fit for the team and I know that he will bring value and add success to our retailer network.”
Lepper has a Bachelor of Science in agricultural economics from the University of Manitoba. In addition, he has been active in the Canadian Association of Agri-Retailers, serving on the board of directors, and acting as co-chair on the stewardship and agronomy committee. He is an active member of the Manitoba Institute of Agrologists.
February 4, 2014 – The Pest Management Regulatory Agency recently announced the approval of a minor use label expansion registration for Revus fungicide for control of downy mildew of basil and phytophthora blight and root rot of ginseng.
Revus fungicide was already approved in Canada on Brassica vegetables, several bulb vegetables, several leafy vegetables, cucurbit vegetables, fruiting vegetables, potatoes, grapes and hops.
The following is a general, abbreviated outline of the new disease registrations on the Canadian label for Revus fungicide. For detailed instructions consult the full Revus fungicide label.
Basil (field and greenhouse)
For control of downy mildew, apply as a foliar spray 583 ml/ha beginning prior to disease development and continue on a seven day interval in appropriate rotations. Do not apply Revus sequentially – always rotate with other registered products from different fungicide groups. Apply in a spray volume of 95 to 280 L per ha. Maximum of four applications per year with a one-day pre-harvest interval.
For control of Phytophthora blight and root rot, apply as a foliar spray and/or drench at 583 ml/ha beginning prior to disease development and continue on a seven day interval in appropriate rotations. Drench applications are required to control root rot. Do not apply Revus sequentially – always rotate with other registered products from different fungicide groups. Apply in a spray volume of 470 to 1,400 L per ha. Maximum of four applications per year with a three-day pre-harvest interval.
Revus fungicide should be used in an integrated disease management program and in rotation with other management strategies. Follow all other precautions and directions for use on the Revus fungicide label.
Already a fungicide for apples and grapes, Luna Tranquility is an all-in-one formulation that includes Group 7 (fluopyram) and Group 9 (pyrimethanil) modes of action. Luna Tranquility provides disease protection against the leaf spot complex (early blight and brown leaf spot), white mold and black dot.
“With a unique Group 7 and 9 mode of action, Luna Tranquility is able to control early blight and brown leaf spot unlike any other previous fungicides,” said David Kikkert, portfolio manager of horticulture for Bayer CropScience.
Early blight and brown leaf spot have recently become less sensitive to existing Group 11 and other Group 7 fungicides in North America, leaving potato growers with fewer effective options. Luna Tranquility offers potato growers an alternative to control these diseases as part of a responsible resistance management program.
In addition to early blight and brown leaf spot control, Luna Tranquility controls white mold and has activity on black dot, helping growers manage many diseases with one product. It can be applied by either ground or air.
“Used in a preventative spray program, Luna Tranquility will help growers combat major yield robbing diseases and produce better yielding, high quality potatoes,” explains Kikkert.
Based out of his home office in Holden, Alta, Micklich will work with both existing and new customers through his retailer experience and vast agronomic knowledgebase.
Micklich most recently was employed with Andrukow Group Solutions as a sales agronomist and special project manager. He holds a diploma in crop technology from Lakeland College.
“Matt is well known and respected in the area, which makes him a natural fit for the Northern Alberta region,” said Dustin Dinwoodie, regional sales manager for Canada. “With his background in the ag industry and his wide array of experiences and knowledge in Canadian agriculture, we know Matt will make a positive impact immediately with Arysta LifeScience customers.”
Nova 40W is a systemic fungicide for the control of various diseases across a wide range of crops. In apples, Nova provides protection against apple scab, powdery mildew and rust. In grapes, Nova provides long-lasting, effective control of powdery mildew and black rot. Additional crops that Nova is registered on include peaches, nectarines, cherries, asparagus, Saskatoon berry, greenhouse tomatoes, peppers, Kentucky bluegrass grown for seed and dozens of ornamentals and flowers.
Nova, a Group 3 fungicide, is gentle on both crops and beneficial insects and is delivered in easy to handle water soluble pouches.
For more information, visit www.dowagro.ca.
"With this minor use registration for Quadris Top, Syngenta is able to offer producers top-notch protection against Botrytis leaf blight, a yield-robbing disease that affects bulb vegetables," states Eric Phillips, product lead for fungicides and insecticides. "Additionally, this Quadris Top registration is aligned with the U.S. registration, giving Canadian producers optimal export flexibility."
Quadris Top fungicide combines the active ingredients azoxystrobin (a Group 11 strobilurin fungicide) and difenoconazole (a Group 3 triazole fungicide). Together, they deliver dual modes of action to systemically control Botrytis leaf blight in bulb vegetables.
Botrytis leaf blight is a common and destructive foliar disease caused by the pathogen Botrytis squamosa and can hinder bulb growth, yield and storage capability. The disease is found on bulb vegetable crops in most growing regions and is particularly troublesome for onions.
"Together, with control of purple blotch, leaf blotch, downy mildew and the suppression of Stemphylium leaf blight, the addition of Botrytis leaf blight to the Quadris Top label offers growers an even stronger fungicide solution in bulb vegetables and complements an existing suite of Syngenta brand products. It is also another example of our ongoing commitment to support minor crops,” said Phillips.
For more information please go to www.syngenta.com.
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