Every year a number of my courgettes succumb to some form of stem rot. I had put this down to squash vine borer, and thought the only possible solution was covering with nets. Well this year, the stem of one courgette plant severed, so i dumped it. Only later I learned I should have sliced the stem vertically, removed any insects and then left it suspended in a bucket of water for a week to re-root before transplanting it.
On Sunday, another plant is beginning to rot at the stem. But close examination revealed no insect infestation. The top of the split was sealed, but careful splicing of the plant revealed no insects inside. The bottom of the splice looked open, but I dreaded digging into the roots, certain this would kill the plant. But now my suspicion is this might not be vine borer but some form of rot. We are at the end of the rainy season, and sometimes it has poured for days. Often the rot occurs in the rainy season in these plants. When I looked at the image of a stem infected with squash vine borer there are similarities with this picture, but they do not perfectly match. Opinions please, is this squash vine borer infestation or is it stem rot due to excessive wetness/humidity, or to some deficiency that can or can't be rectified. Thank you.
