Why do my zucchini, melon and cucumber plants collapse in the summer heat? Is it lack of water?
It is probably caused by squash vine borer. Look for a small hole in the stem near its base. You will probably notice wet sawdust oozing from the stem. Split the stem longitudinally with a sharp knife and remove the borer (a white grub with a dark head). Then pile moist soil over the damaged stem and you may be able to save the crop. You can also try covering the young plants with a floating row cover until the plants blossom.
