When the storage doors open and farmers look at their cured potatoes, they are hoping for high-quality spuds that will garner a fair price. Unfortunately, potatoes can be sneaky. Some don’t reveal problems until harvest, or worse, when they are already in storage. Determining which disease is present allows for better management and application of appropriate controls. However, treatments in potatoes vary and there are no silver bullets. Potato diseases work together to exacerbate each other, and pests help to increase disease risk.
Pests and Diseases
Agriculture Director at McCain Foods Australia/New Zealand: International collaboration to combat tomato potato psyllid
As Agriculture Director at McCain Foods Australia/New Zealand, John Jackson has witnessed the destruction of the tomato potato psyllid (TPP) and the bacterium it vectors – Candidatus Liberibacter solanacearum (CLso), which causes zebra chip disease – in New Zealand’s potato industry for 14 years.
Prince Edward Island’s Department of Agriculture has begun an education campaign to make sure gardeners understand the importance of growing blight-resistant varieties of tomatoes this spring. In 2015, there was a similar education campaign after a new aggressive strain of late blight devastated tomato crops the summer before. The strain, called US 23, primarily attacks tomatoes. But it’s also a concern for the province’s billion-dollar potato industry.
New weapons in the battle against the pale cyst nematode — a major potato pest that has cost US farmers millions of dollars since it was found in southeast Idaho in 2006 — include an effective bio-fumigant and a surprisingly efficient “trap crop.” Researchers are also making progress in developing PCN-resistant potato varieties. “Understanding the biology allows us to target the weak point in the life cycle,” said University of Idaho Associate Professor Louise-Marie Dandurand, project director of the Globodera Alliance.
Control strategies for late blight are constantly developing as the pathogen causing the disease evolves and the available blight chemistry changes, either due to regulation or efficacy shifts due to fungicide resistance, according to independent agronomy company Farmacy Plc in the UK. Overcoming issues such as these is a key part of the Hutchinsons’ blight trials, first set up in 1997. The trial is managed specifically to test products individually under higher blight pressure than might otherwise be found in the field.
Keeping late blight out of potatoes is a season long campaign for growers and one that seems to be getting tougher as the years go by, with seven day spray intervals now standard practice, say crop specialists at UK based adjuvant supplier, Interagro. They point out that with resistance to fluazinam now established in the blight populations and a continuing shift towards more aggressive P. infestans populations, such as 36_A2 and 37_A2, a robust resistance management strategy is essential to safeguard crops and chemistry.
A revolutionary co-formulated fungicide for the prevention of late blight in UK and Irish potato crops will be available for farmers to use during the 2020 growing season.
Late Blight control strategies in the United Kingdom will have to change this season if potato growers are to combat the spread of a new aggressive, fungicide-insensitive/ resistant strain of the disease, leading agronomy firm Hutchinsons says. The dark green 37_A2 form of Phytopthora infestans has quickly spread across Europe, reaching England two years ago when five cases were reported. The new strain is at least, if not more, aggressive than the dominant blue 13 and pink 6, but the crucial difference is that it appears equally aggressive on foliar and tuber blight.
A new camera that will detect crop disease quickly and at a significantly lower cost has been developed by British researchers. The technology could potentially save farmers worldwide thousands of pounds in lost produce, while increasing crop yields. The camera will cost less than £1,000 – about a tenth of the cost of the crop cameras currently on the market.
While the usage of many chemical crop protection products to control nematodes on potato are getting more prohibitive for numerous reasons, many farmers are turning to biological products because they are usually proven to be safe, efficient and economical to use. US based GroPro has a proven track record of delivering natural and organic products. One of GROPRO’s flagship products is Vigilance Nematicide, the companies’ answer to farmers’ need for effective and safe bio-based nematode control solutions, and yet still being able to attain high yields and good quality.
Managing weed control programmes in potatoes could be tricky this year, given the continued dry weather. Dry weather can hamper the activity of residual herbicides, while a lack of soil moisture will also slow the emergence of many key problem weeds until later in the season. However, some of the sneakier ones may grow from depth earlier, unimpeded by a dry and disrupted herbicide layer. This means growers are going to have to choose a robust post-emergence herbicide to tackle weeds when they emerge, said Craig Chisholm, field technical manager for Corteva Agriscience.
Potato farmers in the North Rift in Kenya are staring at heavy losses following the ongoing heavy rains. The crops had been attacked by blight, which has been made worse by the rains. Peter Muga from Kanjo area in Mau Narok is among farmers counting losses after the crop was attacked by the fungal disease. He is using chemicals he bought to contain the disease. He is worried because potato farming is his main economic activity. He sprays the crop weekly at a cost of between Sh1,500 and Sh2,000.
Syngenta unveiled the new TYMIRIUM™ technology platform brand this week. In a press release, the company says it is a novel nematicide and fungicide technology under development for both seed- and soil-applied uses. Based on the active ingredient cyclobutrifluram, Syngenta says TYMIRIUM™ technology provides long-lasting protection against a broad spectrum of nematode pests and diseases across all major crops and geographies.
Bayer announced the registration of the active ingredient, tetraniliprole, which will be launched commercially in the registered end use product Vayego insecticide. For potato growers, the insecticide can be used to control Colorado potato beetles, potato flea beetles and European corn borer.
CIP mapping potato diseases in Africa: Bacterial wilt present in 73% ware potato farms and 50% seed potato farms in Uganda
Bacterial wilt is widespread in Uganda, limiting yields and degrading seed quality. But little is known about the extent of the disease. CIP conducted a nationwide survey to chart the prevalence and spread of bacterial wilt in Uganda, as well as the type of pathogens present. Bacterial wilt was found to be present in 73% of ware potato farms and 50% of seed potato farms.
What lies beneath: WSU team studies three-way interaction between potatoes, powdery scab, and mop top virus
A team of Washington State University scientists are taking on a destructive complex of diseases affecting valuable potato crops. Over the last few years Washington’s potato industry has encountered a new threat: Potato mop top virus, a pathogen that lives in soil and attacks the tuber, darkening the flesh and making potatoes unsellable. Mop top is spread by a protist, a fungus-like microorganism, that causes a disease called powdery scab which blemishes valuable tubers as it infects neighboring plants.
Didier Andrivon from INRA delves into the disease that once killed 1.5 million individuals in Ireland: Potato late blight, also known as Phytophthora Infestans It would be easy to think that a disease peaking over one hundred years ago is no longer a problem, but potato late blight continues to evolve and emerge in new places – similarly to the insidious reach of[Read More…]
Syngenta’s BlightCast tool is now live and running for the 2020 season, to give British potato growers and agronomists a clear picture of impending blight pressure and risks – in time to make active application decisions. “BlightCast showed the first Hutton Criteria hits for the site were on the 16th August, but no Smith Periods were triggered until 24th August; in that time the visual assessment of blight inoculated trials went from virtually nothing detectable to widespread infection,” says Syngenta potato specialist, Rob Farrow.
Didier Andrivon from INRA directs our thoughts to potato and tomato blights in Europe and argues that multi-actor research is crucial for sustainable control. Controlling blight epidemics have long relied almost exclusively on repeated applications of synthetic fungicides. It is not uncommon for potato crops to receive 15 or 20 sprays a season to keep blights at bay. However, this strategy while efficient, is not sustainable.
Controlling late blight (Phytophthora infestans) in potatoes has become much more complicated. Growers and agronomists have to think about many factors, including disease pressure, blight strains, growth stage of the crop, weather conditions, fungicide mode of action, and many more. Blight strains in the UK have changed radically recently and Dr. David Cooke of the James Hutton Institute in Dundee has identified newer strains which are more aggressive, produce more spores from larger lesions and have a faster life cycle.