Bugs killing Zucchini
Squash vine borers cause a sudden wilting of the plant, and left untreated will kill the plant. They bore into the lower portions of the stem and eat their way through the stem tissue. A characteristic sawdust-like yellow frass around squash stems is a telltale sign that vine borers are present. Frass is what the vine borer leaves behind after digesting the stem tissue. If caught early, the individual borers can be removed by carefully slitting the stem open with a knife are removing them and any eggs present, Moist soil should then be mounded over leaf joints at higher points to encourage secondary root formation, since the borer's feeding has likely disrupted the main roots. A cultural way to control these pests is to remember to rotate crop location in the garden each year. Using row cover fabric which lets in light, but not insects, will help prevent the beetles from feeding on the vines. Chemicals effective for both cucumber beetles and squash vine borer are carbaryl and malathion. Avoid using both chemicals together as they can be toxic to the plant. Remember to read and follow label directions. I hope this will help you to have a big zucchini harvest this year.