SQUASH VINE BORER
Begin monitoring your squash plants for the adults, moths that look like black-and-red wasps with metallic forewings. They lay eggs in the soil at the base of squash vines (both winter and summer varieties). The larvae soon hatch and bore holes near the base of the vine. Routine inspection of your plants may reveal a small pile of yellowish-green sawdust-y frass where the vine meets the soil, indicating the point of entry. Larvae gradually eat the inside of the stem, occasionally leaving deposits of frass where they have punctured through the vine wall. Sometime the frass is found oozing from the stem. The borer may even invade developing fruit. Naturally, the vine is weakened and succumbs, either from an inability to absorb water and nutrients or by secondary disease.
Protective sprays with products licensed for squash borer will achieve the best control of this pest. Products containing spinosad, derived from a naturally occurring bacterium, have a low toxicity to non-target organisms. Spray according to directions, making sure the spray penetrates the leaf canopy to coved the stems all the way to the base of each plant. With any pesticide, follow label directions explicitly.
You may achieve some control by carefully splitting the vine lengthwise with a very sharp blade at the point where you see frass, cutting as short a span as possible. Locate and remove the invader, or prick it with a needle or other thin, sharp tool. Gently close the cut and mound soil around it. In many cases the plant can be saved. Be sure to destroy the vines at the end of the season, taking care to remove as much of the vine as possible below the soil line.
Feel free to continue the conversation and add your own discoveries on pest control by leaving a comment. If you have had great success with a particular organic method, let us know what worked for you! Thanks!
ACKNOWLEDGMENTS: The information above was gleaned from the UNH Cooperative Extension Website a GREAT resource!