Update on Potato Crop: Disease and Insects in Manitoba, 2015 Vikram Bisht. Potato & Hort Crops Pathologist, MAFRD, Carman, MB , R0G 0J0

• Foliar diseases – preventative fungicide sprays were often

based on risk of late blight, often on weekly intervals.

• Late blight disease (LBD) appeared in the first week of

September, which is late in season. There were a few fields with

tuber infection. Tuber infection in storage can lead to secondary

infection with softrot and Fusarium dry rots.

• Most seed production fields are top-killed by end of August,

and would have escaped LBD.

• Early blight in general was minor in the fields.

• Powdery scab infected roots were noticed in some fields.

• In water logged patches of some fields iron deficiency

chlorosis was noticed on potatoes.

Cooperators: Agronomists from the potato industry: Scott Graham (McCain), Leon Jarvis &

Landon Thompson (Simplot), Trevor Thornton, Ron Lintott, Steve Saunderson, Kurt Ginter,

Doug Pryor & Darren White (Delta Ag). Lab Support: Manika Pradhan, David Osterman.

Verticillium wilt infection of canola

Possibility of long distance dispersal of microsclerotia with blowing wind

Acknowledgements

Disease Surveys

Photo Courtesy : MAFRI

Vikram.bisht@gov.mb.ca 1-204-745-0260

Survey and Monitoring of Insect Vectors

2015 Dec 16 - 17, MB Agron Conf,

Winnipeg, Manitoba, Canada

MB Potato Sector

• Management of cull potato piles – by spreading in fields to freeze

or feeding to livestock can help reduce risk of spread of diseases.

• Taking steps for on-farm biosecurity, especially removal of soil tag

on farm and service vehicles, can greatly reduce risk of bringing in

to the farm new diseases of concern.

Reference:

• The Economic Contributions of the Manitoba Potato Complex.

Informa econmics. November 2014.

• ECB European corn borer infestation may partly be related to increasing

acres of Bt corn acres

• a, b, c: ECB and damage

• d. Secondary infection by Erwinia spp. causing stem rot disease

• e & f. ECB affected plant died earlier and reduced tuber yield

• Potato is a major crop in Manitoba, with about $270 million farm

gate value. The MB potato complex has over $1.4 billion in

industry output, with $1.0 billion in Manitoba (Infoma Economics).

• Potatoes are processed for fries and chips by 5 companies;

also used as fresh and seed. Total area planted was 67,327 acres.

Process potato made up about 74% of total acres in 2015.

• Average yield of MB crop in 2015 was around 315 cwt per acre,

which is a new record for MB.

• Russet Burbank (68%), Ranger Russet (12%) Umatilla (11%) and

Innovator (9%) are the top processing varieties; while Norland

(24%), Sangre (22%), Viking (10%) and Goldrush (8%) are the top

fresh market varieties by acreage in MB (MASC data).

• Weather conditions permitted timely planting and harvesting

without any major frost event. Though there were a few warm

(>28C) days, the cropping season was generally favourable for

good production, when supplemented with irrigation.

• Aphids spread potato mosaic virus diseases. Aphid monitoring

helps guide seed growers in correct timing the aphid control

insecticides. 2015 data showed very low levels green peach aphids

(GPA) but much higher levels of other aphids. GPAs are most

efficient vectors for virus transmission.

• In a survey, as part of the National survey for potato psyllids

(vector of Zebra Chip disease) none were trapped in Manitoba; but

significant numbers were trapped in Alberta.

Portable Ag Weather Stations – near potato fields, along with permanent stations – used in

late blight forecasting. Risk of late blight. presented as Disease Severity Values in the map

• Samples of potato virus infection symptoms were collected from

fields across MB, and sent to NB lab for virus strain identification.

• The National Potato Virus-Y strain distribution study has found

MB to have increased levels of Necrotic strains of PVY. Necrotic

strain viruses can affect tuber quality for fresh sale and

processing.

• In 2015, nearly 95% of PVY samples had necrotic strain viruses;

while the number was around nearly 80% in 2013.

• Verticillium wilt (V. longisporum) of canola is a new soil-borne

disease reported in Manitoba.

• A survey of prairie fields for Verticillium DNA has been conducted

by CFIA to understand its distribution.

• Clubroot disease of canola – infected plants found in more fields

and many more DNA +ve fields were identified in 2015.

• Incidence of verticillium wilt (V. dahliae) was wide-spread but the

severity was moderate compared to hotter summer years. V. dahliae

may infect canola, but is NOT responsible for canola verticillium wilt.

• In some fields European corn borer (ECB) damage was noticed in

plant tops in mid-to-late July; too late to spray insecticide(s) since

larvae were already inside stems.

• In 2015 the ECB incidence was generally high in MB; and also in

potato crop.

• ECB injury can often lead to bacterial stem-rot infections.

• Later in season, the incidence and severity of injury from ECB

appeared to have increased in some fields, and caused early

senescence; and may have affected yields.

R² = 0.3552

R² = 0.5574

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Early Blight Powdery Scab

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