HORTICULTURE TIPS by Josh Steffen: Early Detection of Plant Health Problems

What we do to one portion of our yard affects the many other relationships in the system. If we immediately sprayed our sunflowers at the first sign of a sap sucking aphid, we might miss the ladybug coming up to snack on a nice aphid steak. Or perhaps we see a plant looking a little out of sorts and assume it is a disease issue, or the opposite, it is a fertility issue, and rush to the store to grab the first solution we see to throw at the plant. We may be throwing money down the drain because we are not really addressing the right problem, or no problem at all.

We take a different attitude and approach at Wellfield Botanic Gardens to the various organisms inhabiting the landscape. We value the biodiversity, recognizing the tangled web of relationships existing in the garden. We also recognize new threat pest and disease issues, like the emerald ash borer or thousand cankers disease, which attacks walnuts. Wellfield practices an organic-preferred plant health management system or integrated pest management (IPM). The goal of such an approach is to utilize other organic plant health practices first with chemical applications as a last resort, greatly reducing chemical applications. Chemicals, when used, should be derived from plant material whenever possible and must comply with and be approved by the City of Elkhart, our close partner in managing this important resource. The key to an organically-preferred method to plant health issues is two-fold: maintain healthy plants and early detection of problems. The best defense is a good offense. A robust, healthy plant is your best defense against issues, so keep them happy. However, plant health issues are bound to occur, so good gardeners are also good detectives.

Wellfield Botanic Gardens joined the Sentinel Plant Network in 2015 which links public gardens, government agencies and the general public. The Sentinel Plant Network trains garden staff how to detect plant health issues and how to communicate concerns with garden visitors. The goal is great a nation-wide network of plant-detective citizens alert for the next emerald ash borer or invading disease.

Here are some tips and basic steps to solving your own plant health mysteries:

  1. Garden patrol – regular walks through your landscape are crucial to spotting something out of place or not looking quite right.
  2. If you spot an issue, first look at the entire plant AND those around it. Is this the only affected plant or are there other plants near by showing similar signs of distress? Does the symptoms look random or is there a distinct pattern? Random patterns are often signs of living organisms as causal agents, while pervasive systematic patterns are signs of environmental causes.
  3. Next, look at the plant up close. Examine roots, undersides of leaves, along stems, trunk, flowers and fruit for damage, holes, eggs, webbing, or spots.
  4. Collect samples for identification. If you take pictures, take several both up close and of the whole plant. If you collect physical samples, take the whole plant if possible or more than just a few leaves, flowers or fruit. Samples of much of the plant will aide yourself or your extension agent later on. Knowing the “history” of the plant, how it was planted and maintained, is useful. Remember the observed insect, animal or disease might not be the primary cause of your problem, so keep an open mind and do not jump to conclusions.
  5. If you cannot easily identify, or want your diagnosis confirmed, contact your extension agent for instructions on how to submit samples. A diagnosis is only as good as the sample material provided.
  6. With a correct diagnosis comes the intelligence gathering phase and a decision to control the problem or not. Know your potential enemy. Know its life cycle and when it is most vulnerable to control. Spraying an insecticide on an adult Japanese beetle is the wrong time to address the pest. Adults are hard to kill, but grubs living in your sod are much more vulnerable.
  7. Should you do something about it? Not necessarily. A pest or disease issue may cause little actual harm to the health of the plant. An organic plant health approach calls for certain aesthetic or economic thresholds to be crossed before acting. If there is very little issue, then leave it alone. Who knows maybe nature will take care of the problem for you and you will not need to sentence another poor innocent insect to death!

Can you name the beetle in the photo above?  Is this insect considered a pest or beneficial? Submit your answer below, the first correct answer will receive 4 free passes to Wellfield!