Bug Hit list Series: Squash Vine Borers Prevention

Identification: 

The easiest to spot in your garden is the adult moth. They are bright red/orange with black stripes and black wings. If you see them then you know to look for eggs. The eggs will usually be found right at the base of your squash vine near the soil in little clusters. To me they look like mustard seeds. If you find eggs and moths start checking all your squash for holes in the base of the stem. If you find holes near the base with "saw dust" (crumbles of your vine from the borrowing) then you have an infected plant. Another way to identify these plant killers is by watching for morning wilt during your scout walks. If any of your vines specifically squash are wilted in the morning start checking for holes at the base of the plant. 

Host Plants:

They are found primarily in squash vines but will also attack zucchini, pumpkins, and even melons. There have also been some reported sightings near potato plants though the larvae will not be there just the moth.

The Damage:

The Vine Borers do exactly what you would expect they bore into the vine of cucurbits (squash, zucchini, pumpkins, and melons) and they feed on the inside of the vine. This feeding process blocks the flow of water and nutrients through the vine. Just like our veins plants have tubes in their vines and stems that carry sap and water to different parts of the plant. When the vine borers eat they break these veins and so the water that the roots soak up can't be delivered to the vine past the point of the vine borderer larvae. The result is that half your plant starts to wilt, and eventually dies.

Prevention Options:

The best prevention is to kill them before they can lay eggs, and removing all eggs before they can hatch and release the larvae. In Kentucky they first start to appear in early April right around our last frost. Depending on where you are they may come out later or earlier for you so we recommend checking with your local extension office if you have one or being on the look out as soon as you plant any cucurbits. If you see the moth try to catch it and get rid of it. If you spot the eggs on your vine gently scrape them off into a bag or your hand and remove them from the garden I recommend burning them but if that's too extreme for you I totally understand throwing them away works too! 

You can also use prevention methods for keeping them out of your garden such as netted row covers so that the moths can't reach your plants to lay eggs. Some growers will put tin foil around the base of their stem as soon as the first true leaves appear again to keep the moth from laying eggs and the larvae from being able to bore into the stem. 

If you do find a hole in your stem with some crumbled green/orange "saw dust" near it then you can try to save your plant but the larvae is inside. Take a knife and cut a slit up from the hole away from the base of the plant. Continue to cut slowly until you find the larvae remove the larvae and kill it. Then put the section of vine you cut a slit in into the soil and cover it so you have for all intents and purposes replanted it. Keep this spot well watered for the next week or so in the hopes it will be able to heal enough to continue to grow. 

Organic Pesticide Options:

You can also try using organic controls like Bacillus thuringiensis, a bacteria found in soil all over the world, in high concentrations it can kill a borer. Inject the Bacillus into the stem at the hole the borer made and directed away from the base of the plant.

While Researching I found the the Minnesota extension office site to be very helpful so check there if you need anymore details!

https://extension.umn.edu/yard-and-garden-insects/squash-vine-borers#physical-controls-3091762