For those that just can’t get enough of peony diseases, here’s a movie of what foliar nematodes can do in peonies. There were some images in my season’s overview, but I think the movie is better still 🙂 It starts with the three infected plants (Old Faithful seedlings, Old Faithful being rather susceptible to this pest) that didn’t receive a hot-water treatment and this is where the problems started. All around it where healthy plants. This is the third year of their growth and you can see that several plants in a circle around the original infected plants are now also showing symptoms. The symptoms at this stage (before flowering) are stunted growth, somewhat less stems and, above all, aborted flower buds. To the left of the infected plants, where the camera first swings to, you have a row of Don Richardson, where you can see the first plants with aborted buds, a bit further the other plants are still growing well. Then when the camera returns you can see the row after it with Fringed Ivory, another lactiflora, with the same symptoms, most visible in less sidebuds as well. Then to the right of the original three you have Color Magnet, a hybrid, that shows the symptoms most clearly. Stunted growth and aborted flowers. You’ll notice that as the camera goes further away that other plants of Color Magnet are very healthy with lots of buds. The most visible symptom is when foliage starts to dry up, ending at the veins as the nematodes have difficulty passing them, but this is only visible much later in the season. You can see some pictures of that in the longer article about foliar nematodes (go to the ‘magazine’ in the menu, or do a search).
PS: It took some time to find out how to upload a movie from my smartphone, never done that before. Apparently the way to do it nowadays is either through facebook or youtube and then ’embed’ it here. Hope it works well.