Diseases
Ontario's hot weather keeps late blight in check but some growers are seeing sunburnt stems and heat stress in their potato crop. 
Published in Diseases
The Pest Management Regulatory Agency (PMRA) completed its re-evaluation of mancozeb and found the continued registration of products containing mancozeb acceptable for foliar application to potatoes in Canada.
Published in Diseases
The results from Ontario spore traps, in Alliston, Leamington, Simcoe-Delhi, and Shelburne areas, returned negative detecting no late blight spores, according to Eugenia Banks’ latest potato update.
Published in Diseases
Agriculture and Agri-Food Canada researchers in Fredericton, N.B. are exploring environmentally friendly solutions to manage Potato Early Dying complex (PED), a disease that is limiting yields in many potato fields in eastern Canada.

PED is a disease complex caused by a combination of a fungal disease (Verticillium wilt) and root-lesion nematodes.

With few available treatments, a process called biofumigation is being used by some growers to manage PED. The process involves tilling mustard plants into the soil at a specific stage of growth with enough heat and moisture in the ground to induce a chemical breakdown of the plant material.

“As the mustard decomposes, it releases a chemical that reduces Verticillium wilt pathogens without adverse effects on the environment,” explains Dahu Chen, AAFC plant pathologist at the Fredericton Research and Development Centre.

As a side-effect, mustard biofumigation also delivers green compost into the soil, improving soil health. There is some evidence that the severity of PED symptoms is reduced in healthy soils.

“The disease has been around for a long time, but it is now identified to be a major factor limiting tuber yield in New Brunswick,” says Chen, who is studying the problem with colleague, AAFC researcher Bernie Zebarth. 

“The pathogen can survive in the soil for a long time, even through the harshest winter conditions of eastern Canada,” explains Chen.

Chen and Zebarth are now working with industry partners, including Potatoes NB and McCain Foods Canada, to determine the effectiveness of mustard biofumigation through trials in commercial fields.

In addition, crop rotations that reduce the severity of PED symptoms are being examined in New Brunswick and Prince Edward Island by Potatoes NB, McCain Foods Canada, the PEIPotatoBoard, the NB Department of Agriculture, Aquaculture and Fisheries and the PEI Department of Agriculture.

Dr Chen examines leaves of potato plant
Dahu Chen, AAFC plant pathologist, examines the leaves of a potato plant for signs of disease. (Photo courtesy of AAFC)



Published in Diseases
Eight spore traps have been set up in potato fields across Ontario to help detect spores of late blight, according to Eugenia Banks' latest potato update.

Two spore traps are located in the Shelburne-Melancthon areas at D & C Vander Zaag Farms Ltd. and two others in the Alliston area at Mark and Shawn Murphy Farms. In the Delhi area, two spore traps are set up at Joe Lach's Farm and Fancy Pak Brand Inc. The final two spore traps are located in the Leamington area at Harry Bradley and Sons Farm. 

Alliance Agri-Turf, Bayer CropScience, FS Partners, Holmes Agro and Syngenta provided funding for the 2018 late blight spore trap project. 

A&L Laboratories in London, Ont. will conduct the polymerase chain reaction (PCR) tests to identify the presence of late blight spores.

The results will be shared with growers and positive PCR tests indicate the presence of spores. Early detection helps alert growers to add late blight-specific fungicides into their mix.

In the past two years, Eugenia Banks, a former potato specialist for the Ontario Ministry of Agriculture, Food and Rural Affaris (OMAFRA), led a project evaluating passive spore trapping technology to help growers improve late blight management. The project recorded positive results. Spores were detected 15 days on average before late blight lesions were seen in a few fields. A previous Potatoes in Canada article goes indepth into the project and how effective spore traps are for preventing late blight

“Spore traps represent another tool to be added to the potato growers’ arsenal to combat late blight,” Banks says. “If late blight spores are not detected by the traps, growers should still follow a preventative fungicide program and apply a fungicide spray before rows close. Also, fields should be scouted regularly.”
Published in Crop Protection
Potato virus Y (PVY) affects both yield and the quality of the crop, making it one of the most dangerous diseases faced by commercial potato producers. Spread by aphids and through infected seed lots, PVY has been managed with varying levels of success by Canadian growers for many years, but the rise of more aggressive and faster-spreading strains has made it even more challenging to control.
Published in Diseases
As spring arrives, potato growers are concerned about Dickeya, and Eugenia Banks, the Ontario potato specialist, has some points of interest to share.

Potato seed infected late in the season with Dickeya (new blackleg) usually does not show symptoms in the field before harvest nor in seed storages. This is because Dickeya requires high temperatures for the development of visible symptoms. The optimum temperature for Dickeya is above 25 C. 

By contrast, the old blackleg (Pectobacterium) can develop at cool temperatures (8 C to 10 C), and symptoms are usually visible when cutting seed.

Banks says she received two questions about Dickeya: 

Q: If dormant infection of Dickeya is suspected, could you incubate a sample of tubers at 25 C to 30 C so the tubers will show Dickeya symptoms in about 2 weeks?
A: Banks asked Steve Johnson (Maine) and Gary Secor (North Dakota) this question and both said no. It takes more than two weeks for the symptoms to develop. Banks says the first time she saw Dickeya symptoms developing from seed tubers with dormant infection was in late June (the seed tubers had been planted by the middle of May), and both Johnson and Secor agree. 

Q: Are Dickeya lesions smelly?
A: We all know how smelly the old blackleg is. The slimy, black stems smell like rotten fish, a disgusting smell noticeable at least 30 feet away from an infected plant. Usually Dickeya is not smelly. The bacterium grows inside the stem moving up in the vascular tissue. Dickeya-infected stems are usually dark brown, not inky black, slimy and smelly like the old blackleg. Eventually, the infected stems may be invaded by secondary bacteria that cause a black rot. If, shortly after emergence, you see small, wilted plants with a black stem base, it is probably the old blackleg. If the summer is cool and wet, probably the old blackleg will prevail. In hot summers, Dickeya will be the prevalent disease (wilted foliage is also a symptom of Dickeya).
Published in Diseases
Chemicals in the leaves of potato plants, produced naturally by the plant, may hold the key to a new way in controlling Colorado potato beetles. Agriculture and Agri-Food Canada (AAFC) research scientist, Helen Tai (pictured here) has turned to the leaves growing on wild potato relatives – leaves that Colorado potato beetles won’t eat – as a new approach to keep the pest away.
Published in News
After a final holding temperature is achieved in storage, it is important to ventilate properly in order to manage the byproducts of respiration, ensure a uniform temperature and an ideal environment for the duration of the storage period, which will maximize the value of the crop.
Published in Storage
What potato grower wouldn’t want to add dollars to their bottom line? By reducing the bruising that occurs during harvest by one percent, thousands of dollars could be added to the bank, according to research completed at the University of Maine. The solution is to minimize the potential for bruising before the harvester enters the field, but growers in a hurry often overlook this most basic crop management rule.

Published in Storage
Syngenta Canada Inc. has announced Orondis Ultra fungicide is now available in a premix formulation for added convenience.
Published in Diseases
A genetically improved potato designed to have resistance to a devastating global plant disease has successfully come through the first year of field trials.

The field trial conducted by The Sainsbury Laboratory (TSL) in Norwich involves incorporating late blight resistant genes from a wild potato relative into a cultivated Maris Piper potato. READ MORE
Published in News
For the first time, evidence of the zebra chip pathogen has been found in potato fields in southern Alberta.

An infected potato psyllid insect carries the Lso (Candidatus Liberibacter solanacearum) pathogen that can cause zebra chip disease in potato crops.

Zebra chip has affected potato crops in the U.S., Mexico and New Zealand and caused millions of dollars in losses. Potatoes with zebra chip develop unsightly dark lines when fried, making affected potatoes unsellable.

The first detection of Lso came from sampling cards collected at one site south of Highway 3, near Lethbridge, Alta. For the full story, click here
Published in Diseases
The potato person who said many years ago "A potato storage is not a hospital" was absolutely right. Diseased or bruised tubers do not get better in storage. Tubers bruised at harvest are easily invaded by soft rot or Fusarium dry rot, which can cause serious economic losses in storage.

Harvest management, in large part, is bruise management. Bruising also affects tuber quality significantly. In order to harvest potatoes with minimum tuber damage, growers need to implement digging, handling and storage management practices that maintain the crop quality for as long as possible after harvest.

Assuming all harvest and handling equipment are mechanically ready to harvest the crop with minimum bruising, there are several tips to preserve the quality of potatoes crop during harvest:
  1. Timely Vine Killing. Killing the vines when tubers are mature makes harvesting easier by reducing the total vine mass moving through the harvester. This allows an easier separation of tubers from vines.
  2. Timely Harvest. Potatoes intended for long term storage should not be harvested until the vines have been dead for at least 14 days to allow for full skin set to occur.
  3. Soil Moisture. Optimal harvest conditions are at 60-65% available soil moisture.
  4. Tuber Pulp Temperature. Optimal pulp temperatures for harvest are from 500F to 600F. Proper pulp temperature is critical; tubers are very sensitive to bruising when the pulp temperature is below 450F. If pulp temperatures are above 650F, tubers become very susceptible to soft rot and Pythium leak. Pulp temperatures above 70°F increase the risk of pink rot tremendously no matter how gently you handle the tubers if there is inoculum in the soil.
  5. Tuber Hydration. An intermediate level of tuber hydration results in the least bruising. Overhydrated tubers dug from wet soil are highly sensitive to shatter bruising especially when the pulp temperature is below 450F. In addition, tubers harvested from cold, wet soil are more difficult to cure and more prone to breakdown in storage. Slightly dehydrated tubers dug from dry soil are highly sensitive to blackspot bruising.
  6. Reducing Blackspot Bruising. Irrigate soil that is excessively dry before digging to prevent tuber dehydration and blackspot bruising.
  7. Bruise Detection Devices. Try to keep the volume of soil and tubers moving through the digger at capacity at all points of the machine. If bruising is noticeable, use a bruise detection device to determine where in the machinery the tubers are being bruised.
  8. Do not harvest potatoes from low, poorly drained areas of a field where water may have accumulated and/or dig tests have indicated the presence of tubers infected with late blight.
  9. Train all employees on how to reduce bruising. Harvester operators must be continually on the lookout for equipment problems that may be damaging tubers. Ideally, growers should implement a bruise management program that includes all aspects of potato production from planting through harvest.
  10. Harvest when day temperatures are not too warm to avoid tuber infections. Storage rots develop very rapidly at high temperatures and spread easily in storage. If potatoes are harvested at temperatures above 27o C and cool off slowly in storage, the likelihood of storage rots is increased. If warm weather is forecast, dig the crop early in the morning when it is not so warm.
Published in Harvesting
All the isolates of late blight -Phytophthora infestans tested were US-23 for 2017. No new late blight incidence has been reported in the last week, which has generally been dry, warm and windy. The 7-day DSV accumulation for late blight risk has been essentially minimal. Harvest has begun in many areas.

The warm conditions has slowed the harvest of some processing fields, to prevent bringing warm tubers into storage. The seasonal accumulated precipitation has been 50-70% of normal in the potato growing areas (Fig1). The soils are generally on the dry side (Fig 2), but irrigated fields have sufficient moisture for a good harvest. READ MORE
Published in Diseases
There’s no current technology to detect acrylamide precursors quickly and without destroying the spud, but a new technique developed by Lien Smeesters from the University of Brussels might help weed out potentially toxic potatoes before they even go to market. In Smeesters’ design, a laser uses infrared light to detect acrylamide, which scatters the light in a unique pattern, instructing the machine to knock the toxic potato out of circulation. | READ MORE

Published in Diseases
With planting season just around the corner, researchers at Agriculture and Agri-Food Canada are reminding home gardeners to take precautions to prevent the infection and spread of late blight. Planting clean and disease-resistant seeds is the best way to prevent the spread of late blight to other gardens and potato farms.

What is late blight?
Late blight is a disease caused by an organism that produces a white fuzz on the underside of leaves which releases millions of spores that float through the air to infect other plants. The spores land on a susceptible leaf, germinate, and cause brown oily lesions. The spores splash on the ground and infect potato tubers, which become brown and rusty looking, with a granular texture. Crop losses due to late blight can cost the Canadian potato industry tens of millions of dollars annually.

Protecting the potato industry
AAFC late blight specialist Rick Peters says taking steps to prevent the disease from infecting potato crops is important to help protect the health of the industry. He advises home gardeners to ensure their tomato seeds are resistant to the US-23 strain of late blight. Resistant seeds can be purchased at most garden centres. Certified disease-free seed potatoes can also be found at garden centres or purchased from a local seed potato grower. Peters says potatoes grown from last year’s garden or those bought from the grocery store are not suitable for planting as these tubers have not been tested and certified as disease-free and could be susceptible to a variety of potato diseases.

AAFC has partnered with industry leaders to identify and track late blight strains in production areas across the country. Scientists are also looking at biological characteristics of the different strains including how they respond to treatments. This knowledge allows for better management and control of the strains in Canadian potato and tomato production areas. While scientists continue to study the disease, they maintain that an ounce of prevention is worth a pound of cure and home gardeners have an important role to play.

If you spot a suspected late blight infection in your garden this season, please contact the Department of Agriculture, Aquaculture and Fisheries at 1-866-778-3762 for information on how to properly dispose of infected plants.

Published in Diseases

Sept. 29, 2016 – Second growth is a physiological potato problem induced by soil temperatures of 24 C or above and water stress. These two factors interact to limit the tuber growth rate, causing second growth. Inadequate soil moisture alone does not result in the initiation of second growth.

Heat and drought prevailed during the 2016 Ontario growing season, which explains why second growth has been reported in some fields.

Potato varieties differ in their susceptibility to second growth. European varieties appear to be more susceptible because they were bred and evaluated in countries where the growing seasons are rarely hot.

There are three distinct types of second growth:

Tuber chaining: A series of small tubers are produced on a single stolon.

Heat sprouts: Sprouts develop from stolons or daughter tubers. The sprouts may emerge from the hills developing into leafy stems.

Secondary Tuber: Small tubers form on daughter tubers. The secondary tubers are formed on short sprouts or directly on the tuber surface. This disorder is usually associated with physiologically old potatoes. High temperatures and water stress during the growing season are major factors contributing to the physiological aging of potatoes.

Cultural practices that promote uniform growth of plants and tubers throughout the season help minimize second growth. Among them are:

● Do not plant physiologically old seed in cold, dry soil.
● Space seed pieces as uniformly as possible at planting.
● Apply an adequate amount of fertilizers.
● Maintain uniform soil moisture sufficient to meet crop needs (this was easier said than done this past season!).

 

 

Published in Crop Protection

Sept. 29, 2016, Ontario – The potato IPM training module, an educational tool with information for the common insect pests, diseases, viruses and disorders of potatoes in Ontario, is now available online. | READ MORE

Published in Diseases

Sept. 8, 2016 - Although harvest of the late maturing crop has not started yet, it is never too early to start thinking about disease management in 2017. Two fungicides to keep in mind in 2017 are QUASH for early blight and Revus as a seed treatment for late blight.

Published in Diseases
Page 1 of 4

Subscription Centre

 
New Subscription
 
Already a Subscriber
 
Customer Service
 
View Digital Magazine Renew

Most Popular

Latest Events

Ontario Potato Field Day
Thu Aug 23, 2018 @ 3:00PM - 08:00PM

We are using cookies to give you the best experience on our website. By continuing to use the site, you agree to the use of cookies. To find out more, read our Privacy Policy.