If you’re testing your water, it’s likely because you either a) have an undiagnosed disease problem in your greenhouse already, or b) you want to head off any issues that could be caused by your cistern, roof water, or water lines. Even with disease symptoms present, It can be difficult to nail down which pathogen is the culprit without a DNA test.
Overall, DNA tests are the gold standard, for many reasons. First of all, DNA doesn’t lie. It’s surprising how much symptoms from one disease look like another sometimes; even an expert with years of experience can make a mistake when it comes to diagnostics from just signs and symptoms. Especially diseases that cause root rots. With DNA tests, you can be sure. Secondly, they can screen for multiple pathogens. One of the DNA tests available, the DNA multiscan®, does just that – scan for multiple pests at one time. This test can point towards a disease issue you might not have even considered. You can choose to look specifically for fungi or bacteria or both.
Multiple samples can determine where a problem is coming from. If you take samples from multiple points along with your water system, and disease issues are only detected in one area (e.g. a secondary holding tank), or are especially high in one area, this can narrow down the source of the problem. This can potentially save you thousands of dollars in crop losses and unnecessary fungicide application by eliminating recurring disease issues at the source.
Interpreting result
Despite the benefits of DNA analyses, as with any tool, they aren’t perfect. They require some know-how (or asking experts) to provide the correct interpretation of results. You still need to be an investigator of sorts and use your DNA results, PLUS other pieces of information, to come to the right conclusions.
An example of the output from a DNA multiscan test. It’s often useful to run the results of your DNA lab tests past a disease expert, as some fungal species have beneficial strains, and “high” loads of a certain pathogen don’t always mean it’s the main culprit.
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