Powdery mildew found on squash plants is cause for concern.
by Gene Henson
For most of us, late August and early September means our garden is nearing it’s peek production, or may be a bit past. It’s also a time when many garden pests are most prolific. And it’s not only crawly and flying pests either. With high humidity and cooler nights fungi and various mildews can run rampant in the home garden.
This morning, on my tour through the garden, I saw powdery mildew on my squash plants. Now, this certainly is a cause for concern, but it’s a bit late in the growing season, and the only really effective treatment would involve the use of fungicides. I will continue to harvest the squash, and watch the progress closely. If they last the month, very good. If not, I will pull the plants and bag them up and put them in the trash.
It’s very important that you not put infected plants in your compost heap. Also, be sure to gather up any fallen leaves around the effected plants, even those from a different species. This also includes any mulch that was around the plants. These spores can and will winter over, and when spring comes, they release conidia, which is a fancy word for sexual spores that are shot up into the air and are blown all over the place starting the cycle once again. If I saw this, let’s say in the middle of July, I would be much more concerned and I would have begun a fungicidal treatment. But this late in the season, I’ll just watch and pull them out later.
Another type of mildew around now is called downy mildew and should be taken a bit more seriously. Downy mildew can be found on cucumbers, melons, all cucurbit crops. It can also attack basal plants. But the most common target is cucumbers. Downy Mildew can also disseminate a grape vine in a very short time, completely destroying all your delicious grapes.
There are organic fungicides available to treat downy mildew; a check at your local garden center will point you in the right direction there. But as with all pest treating products, it’s very important to read the label, and apply strictly as per the instructions.
A little preparation can go a long way toward keeping this nuisance from beginning in the first place. The first step is housekeeping. When the garden is put away for the winter, be sure and remove all plant debris – especially if you have experienced any form of mildew the previous season. The nasty spores can and will over winter. Once they have found a home, they tend to stick around.
Next, be sure that plants are pruned and weeds kept at bay so that their is good air circulation around the plants, particularly around the bottoms. Growing cucumbers on trellises is a very effective deterrent.
Gene Henson is a University of Connecticut certified Advanced Master Gardner.
