Let's Talk Squash
Did you know the yellow and zucchini squash you purchase, unless you buy organic, has a GMO pedigree? Squash is notoriously hard to grow because of constant problems with squash bugs and the dreaded squash vine borer.
Courtesy of Bing Images
The squash vine borer larvae hide within the stems, eating the plant until they leave the vine as an adult vine borer moth. It's hard to catch until your squash plants have started to bloom and begin to produce fruit; then, they wilt. This is why it's hard to find organic yellow and zucchini squash (non-organic is modified to deal with these squash bugs).
Hollow stem squash, such as yellow and zucchini squash, tends to have the most problems with borers. In contrast, other squash varieties, such as butternut, acorn, Tatume, Trombetta, scalloped squash, and pumpkins, tend to have fewer problems. They can withstand the attacks of the borer and send new growth despite any damage.
Natural Ways to Repel Squash Bugs & Borers
Along with planting your squash plants or seeds, plant onions and radishes. These vegetables grow under the soil and don't need much space like other vegetables; they can be planted in between, maximizing your production. The onions and radishes are a natural repellant for the moths from laying their eggs around the squash stems.
Using ground-up bay leaves and trimmings from herbs such as thyme, oregano, and savory, spread this on top of the soil around the planting area. This will confuse the vine borer's detection of newly planted squash.
After planting, apply a lightweight polyester row cover over the new plants using garden hoops. Make sure that the covering is fastened securely to the ground. The hoops will keep the cover off the plants directly, protecting them from the moths being able to lay their eggs and allowing air, light, and water to reach the plants. You will want to keep them covered until the female flowers appear. The first squash blooms are male flowers. The female flowers will have small squash at the base of the flowers. When you see the female flowers, you will want to remove the covering so your natural pollinators (such as bees) can pollinate the flowers for your squash to grow. By this time, the plants are a little tougher and not an easy target for the moths, so there is less chance of your crops being compromised.
Continue to ground up bay leaves and herb trimmings and spread them on top of the soil around the plants.
These methods will not wholly avoid squash bugs and vine borers, but they will help you to achieve many weeks of harvest.
Pull up your squash plants and thoroughly check the stems for worms when your harvest is over. You will want to kill or dispose of them by enclosing the vines in decomposable bags and discarding them in the trash. This will help you control future generations of moths (keeping your pest control under control and minimized) and ensure you don't contaminate any of your other plants. I recommend decomposable bags because we are an environment-friendly farm. By the time they naturally decompose, the worms will be dead and decomposed.
Courtesy of Bing Images. (Left) Adult Vine Borer Moth. (Right) Damage from Squash Vine Borer & Worm.
What To Look For During Your Inspection
Look for a tiny hole in the stem with insect waste nearby. This is a sign of a recent borer invasion (as shown above). The worms are usually hiding farther up within the stem.
Look for any reddish to amber pear-like eggs either on leaf tops, in leaf axils, or on the stems themselves.
You will want to watch for the above during the growing and harvesting process. If you find any eggs, remove them immediately and dispose of them (yes, you will want to kill them). If you find any damaged plants, be sure to remove the plants so the rest of your plants do not get infected.
Some gardeners find it helpful also to use nematodes. Nematodes control ants, fleas, pill bugs, and many other soil-dwelling insect pests, which are a good investment.