I figured out how to insert the picture:

I was hoping somebody might have seen a hole like the one on my zucchini before. :(

I don't see any signs of wilting / stress on the plant so don't want to slice the stem open if there wasn't something in there to take out.

I'll just keep an eye on it for now I guess.

It doesn't look like a squash borer. It looks like your pumpkin is developing either a a flat vine or double stem. Which generally isn't wanted though the plant will live. This early in the game you could plant more seeds if you only space for one good plant. Otherwise I say leave it and see what happens. I have included some pictures of the symptom further along in Atlantic Giant pumpkins (from bigpumpkins.com). As you can see it is a flat wide vine with far more leaves and flowers than what should be. A zucchini is already VERY compact I have no idea what will happen if you let this grow in theory you will have a lot more flowers (both male and female) and leaves in the same amount of space but I imagine harvesting them will be next to impossible because of how dense everything will be.

And here is a complete monster:

Thanks Weirdtrev,

I appreciate your feedback. It's good to hear that it doesn't look like SVB and the info and pics you included were very interesting.

It seems the hole on my plant is getting elongated as the stem grows. I'll keep an eye on it and take some pics as the weeks go by to see what happens.

It's been a week since I noticed the hole and the good news is that there isn't any wilting of the stem / leaf.

As the stem grows, the hole has grown elongated and ants seem to like to explore in the stem now.

Ants are usually a sign of aphids. The ants bring aphids in and "ranch" them, as a source of food. Smart little things... I would put something out to kill the ants and then spray the plants with water for several days to get rid of the aphids.

Ants themselves are pretty harmless to plants and I don't have an aphid problem to be worried about. There will naturally be a few aphids on many plants but I'm not going to kill ants and ladybugs because of it.

Luckily, the hole in the stem wasn't a squash vine borer. The Zuchinni plant has been very healthy and growing like crazy. It just got a huge female flower today but unfortunately no male flowers yet.

Today I noticed that there were a lot of ants inside the squash flowers. They, like bees, like the nectar. Definitely they were not there to raise aphids. I have not seen any aphids around. so they could not make my squash plants their aphid ranch (grin!). I find ants sometimes too intrusive and inconviniet but generally, they are not pests. Actually they eat some insects especially the turmites. That is why you find them where logs are, where turmites are also.

one of my gourds stems was partally(about a quarter of it) was eaten. I sprayed it and wrapped it with paper towel.
It has been 3 daysnow but so far the vine is fine and growing more tha half a foot a day.

Question:
How can you prevent vine borer from boring ? any spray ?