Knowing Your Roots

Posts tagged ‘Potatoes’

IPM – Continuously improving the way we manage pests on our potatoes!

Blog 12Integrated Pest Management – or IPM for short – sounds big and combative, but in reality, it is a basic concept that has become a part of the fabric of agriculture that helps farmers limit pest populations (insects, weeds and diseases) and prevent pests from creating havoc in our crops without relying completely on chemical pesticides.  In the world of potatoes, Wisconsin growers were early pioneers of biologically-based IPM and are recognized nationally for their adoption of advanced approaches for managing pests in their crops.

What is IPM and how is it done?  As it’s name implies, IPM integrates a wide range of tactics that hold pest populations below damaging levels. These can range from biological and cultural approaches at the local level to regionally-based systems that predict and geographically track pest locations and numbers.  It is a basic approach where you get to know everything there is to know about your crop’s pests – where do they come from and when, how do they behave and why, what are their vulnerabilities – and then determine which practices can be best used to exploit these pests and prevent them from entering their crop or causing damage after they do. IPM integrates basic practices such as moving crops in the landscape to make them harder to find, scouting to determine which pests are where, physical barriers to foil entry, tillage and smother crops to limit weeds and predicting pest development with more advanced practices, such as varietal resistance, advanced technologies to diagnose problems quickly and accurately, and using ecologically based processes and geo-referencing to track populations across broad regions. All of these fit under the IPM umbrella, and pesticides are used only when necessary to prevent damage.   (more…)

How do potatoes get to your holiday table? – It all begins with the seed!

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Potatoes, we love them, particularly at this time of year. Thanksgiving is close, and it just would not be the same without those creamy mashed potatoes to accompany your turkey and cranberries. Did you know that Wisconsin ranks 3rd in US potato production?  Did you know that the potatoes you are enjoying actually began life anywhere from 5-8 years before they got to your plate?  Probably not, but during the next few blog posts we would like to introduce you the exciting journey that your potato takes from a lab in Madison, to isolated farms in pristine Northwest Wisconsin and even a trip to Hawaii for a lucky few. This is the process needed to produce the disease-free seed tubers that potato growers must plant to meet all your culinary potato needs.  We hope these next blog posts will help illuminate this fascinating journey.

Potatoes are not grown from actual seeds, but come from daughter tubers (seed pieces) that carry all the traits of the mother plant. To be certain that plants are disease-free, true to variety and carry only the traits such as color, texture and taste that consumers desire, the journey starts in labs on the University of Wisconsin-Madison campus.  The Wisconsin Seed Potato Improvement Program, the first of its kind in the US, is funded by Wisconsin potato growers and directed  by Dr. Amy Charkowski of the UW-Department of Plant Pathology. Here, disease-free potato plants representing hundreds of varieties and characteristics are maintained. In the winter, tiny tissue slivers are grown into small plants in sterile test tubes. These tiny plants, the forerunners of your favorite baked or mashed potato, are then cut into even smaller pieces and grown into plantlets that have roots and leaves of their own.  Every spring, thousands of these plantlets are driven from Madison to an isolated UW Elite Seed farm in northern Wisconsin, close to Rhinelander. Once there, they are placed in protected hydroponic greenhouses, where they can grow over the summer and produce hundreds of pea to marble-sized mini-tubers, which represent the future of the potato industry. Over 400,000 mini-tubers are produced in Wisconsin using this method every year.   (more…)

Band Aids® won’t help these potatoes?

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Like humans, potatoes develop scabs. Although they look similar – raised, rough, brown growth on the surface of the skin – they are fundamentally different. The scabs you got when you scraped your knee as a child are part of the human body’s natural healing process. When the scab finally falls away, new, unblemished skin is left underneath. In contrast, potato scabs are a disease that infect the tuber skin; these scabs don’t heal and can even get worse as the disease progresses.  A better name would be “potato ulcers.”  Ulcers are open wounds that are slow to heal, originally thought to be caused by factors such as stress or skin irritation but later, were shown to actually be caused by bacteria.

Potato common scab is caused mainly by the bacterium Streptomyces scabies. The scabs produced by these bacteria are largely cosmetic and limited to the surface of tubers, but they drastically reduce marketability and are rated as one of the top 5 potato diseases in the U.S. Common methods of controlling infection – using pesticides and increasing irrigation – are expensive and often ineffective. In organic production, scab can be the major cause of tuber rejection. This is a classic example where breeding a potato with natural immunity to common scab is the most effective and perhaps the only realistic approach to managing this serious disease threat. There are currently no varieties of cultivated potato that are immune to common scab, but wild potato species offer a wealth of genetic diversity and have long been viewed as a potential source of desired traits such as disease resistance. Researchers at the UW-Madison have identified a line of the wild potato species Solanum chacoense from South America that is highly resistant to common scab and a closely related line that is susceptible.    (more…)

Measuring Sugars to Arrive at the Perfect Potato Product

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Sugars are a major concern for the potato industry. As consumers, we demand a year-round supply of high quality potatoes to eat.  When processed, we expect the perfect, blond chips and French fries we are addicted to. However, to ensure this year-round supply, tubers must be stored at carefully controlled temperatures and humidity’s for up to 9 months to maintain the balance of sugars needed to ensure acceptable processing quality. This is a major challenge for the industry, as potato tubers are living, breathing entities that seem to have their own agendas when it comes to storing them for longer than they are designed to be kept.

If we store potatoes at temperatures that are too high, the tubers soon realize that it is time for a new year to begin and within a few months they adjust their internal physiology and sugar balance to produce sprouts and start to grow. On the other end of the scale, if we store potatoes at temperatures that are too low, we can slow everything down and store tubers for long periods without sprouting, but only at the expense of disrupting the balance among the complex of sugars that give tubers their characteristic flavors and, worse yet, cause chips and fries to turn dark brown when they are processed! To find the middle ground where we can have long term storage without disrupting the delicate balance of sugars needed for taste and processing, we need tools that enable us to monitor what sugars are present and how these change under different storage conditions.   (more…)

What makes a potato beautiful?

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Today’s potatoes suffer from lowered self-esteem due to constant bombardment from the media’s perception of the “ideal potato.”  This phenomenon first emerged in 1952 with the debut of Mr. Potato Head.  Here was the plastic representation of what a potato was supposed to look like — only two eyes, smooth, unblemished skin and that perfect oblong shape that was designed to be baked and filled with goodies. No mention of the myriad of nasty diseases that are likely to attack a real potato during its life. In recent years, this popularized image has only gained traction due to Mr. Potato Head’s breakout role in the box office hit “Toy Story.” This media exposure is sending a message to our potato youth that in order to be beautiful they should ignore life’s realities and emulate a plastic toy.

But help is on the way! Scientists in the University of Wisconsin potato breeding programs are working hard to help young tubers grow-up in the field to reach the size, shape and taste that consumers want, without succumbing to all those nasty diseases. In our lab, we are employing advanced techniques that enable potato varieties (already accepted in the marketplace) to have all the qualities that consumers want and resist infection from diseases without the need for grower intervention. In my project, I am working with one of the most widespread and destructive diseases of potatoes, aptly named early dying. This disease is caused by a fungus called Verticillium that attacks through the roots and clogs the plant stems causing them to wilt and die prematurely. The fungus persists in soil for multiple years and growers have few options other than fumigation or extending the time between potatoes to multiple years, which are both hard on the pocketbook!   (more…)

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