Issue link: http://read.uberflip.com/i/775473
WWW.POTATOGROWER.COM 51 It is important to bear in mind that the only way to determine the actual amount of PVY in a seed lot is to test every plant or tuber. Since this practice would be neither practical nor economically viable, the amount of virus in a seed lot is estimated based on the submitted sample. Unfortunately, there is an expected and unavoidable margin of error associated with sampling. As a result, an individual sample may under- or over-estimate the amount of virus in the seed lot. The precision of the estimate provided by the post-harvest sample is dependent on a number of factors, including sample size. Most important is the collection of a sample that is representative of the seed lot. Seed growers typically select a representative sample by systematically collecting tubers while placing the crop in storage. However, this goal can be challenging if the seed lot is very large or is not homogeneous. In these cases, we recommend that growers submit extra samples and/or subdivide lots so that better estimates can be obtained. Finally, the type of plant tissue tested (leaf vs. sprout vs. dormant tuber) can influence the estimate provided by the post-harvest test. It's important to note that some pathogens are not uniformly distributed within the plant tissue, so even if a sample is representative and sufficiently large, it can still result in a test result that does not match field observations. To summarize, post-harvest test results are estimates only. When purchasing a seed lot, buyers should request a North American health certificate. This document not only provides post-harvest test results, it also gives additional details, such as the type of testing and sample size, that can be useful in evaluating those results. 541-998-0300 iControl Remote Anytime. Anywhere. • Easily manage your irrigation systems remotely. • Uses a built-in SIM card which automatically selects the preferred network. • Doesn't require you to change your existing panel. • An intuitive platform provides real-time notifications and alarms. • Can be used with all pivot brands available on the market. • Simple to install, easy to use. 164830PieCor13s.indd 1 1/10/17 4:41 PM 162809Baicor13s.indd 1 10/25/16 2:58 PM