Thoughts on Squash Vine Borers

To celebrate the first day of October, I harvested my pumpkins. Successfully growing pumpkins this year makes me feel very accomplished. It is the first time I have had a pumpkin harvest from my own garden since I have been living in Michigan. In the past, when I planted them, the squash vine borers quickly infested the stems, and the plants would die a slow and horrible death, leaving me with one or two immature green pumpkins. This year though, I was determined to outwit the borers.

None of the research I did was encouraging. The consensus across the board was that no matter what organic methods you take, you are going to end up with dead vines and few, if any pumpkins. But, today I am here to tell you---yes, it is possible to have organically grown pumpkins and squash in spite of the dreaded squash vine borers.



Baby Bear Pie Pumpkins

In late June I set to work fighting the squash vine borers. The plants were about 2 weeks old. The three  most reasonable suggestions I had read where to lay foil around the base of the plants to confuse the borers, put oil on the stems weekly to suffocate the eggs, and to hand pick the eggs at least once a week. I decided to try a combination of the three.

I foiled about half my plants--I didn't do them all so that I could compare them with the plants that weren't foiled. I honestly don't think the foiling made any difference. It was a lot of work and I have decided not to do it next year.

Oiling the stems was a lot messier and more time consuming that I thought it would be be--but I was treating 12 hills of pumpkins, 4 hills of winter squash, and 6 hills of summer squash. It took me all morning (3-4 hours) to complete this task each time I did it. If you were just doing a few hills, it wouldn't take that long. At first I tried to apply the oil with a rag, but that got so dirty I ended up just using my fingers. Oil and dirt don't mix very well. I had very dirty, hard to clean hands and finger nails by the time I was done. I used a high quality olive oil--I was going to use cheap vegetable oil, but my husband pointed out that extra virgin olive oil is very hard to wash off of dishes, so wouldn't that be better to use? It wouldn't wash off so easily in the rain.

Before oiling the stems I inspected the plants carefully for eggs and picked them off. This was easy, but also time consuming. The eggs are small, but dark and are easy to see.

I oiled the stems and hand picked eggs once a week from June 27th to July 10th. When I went out the next week to do it, the plants were vining heavily and it would have caused damage to the vines to try to get to the stems.

The vines did eventually get infested with borers, but the oiling and picking the eggs off gave the plants a chance to grow and become healthy and vibrant before the borers started to sap the strength out of them. Most of the pumpkin vines did die the last few weeks of September, but not before 95% of the pumpkins ripened. As for the summer squash, for the first time since I've been in Michigan, I had too many of them. In fact, zucchini and yellow crooknecks are still going strong. I made a huge batch of zucchini muffins today as well as a pasta dish with yellow squash. I've filled a freezer half full of squash.  I've never had summer squash this late in the year.  



Pumpkins and squash lined up on our balcony.

The extra work and effort was well worth in my opinion. Next year besides oiling the stems and picking off the eggs, I want to try putting tanglefoot around the stems to catch the moths as they lay the eggs. This is my own idea and I haven't seen it any  where else. It will be interesting to see if it helps as well.

What about you--do any of my readers have a tried and true way of dealing with squash vine borers?

Linked to Farm Girl Friday, The Barn Hop, and Garden Life.