Pest/Eggs on Zucchini Fruits - Can you Identify?

[Chuckers]

I have the usual 3 pests that attack my zucchini plants every year, but never any pests that attack the actual zucchini fruits.

But about 3 years ago I harvested one zucchini that was resting on the mulched ground below it and found that some pest had eaten the surface of the zucchini and laid these almost perfectly round white, pearly eggs. This pest did not enter the zucchini itself (no holes), merely ate the zucchini about 2-5mm on the surface. This has never happened before that year or since, only that one year and only on 1 zucchini and the damage and eggs were only on the part touching the mulched ground.

Every year since it happened, I think about it and I do google searches but I am never able to uncover what pest did this.

This is definitely not cucumber beetle (spotted or striped) , squash vine borer or squash bug eggs or damage. I have all 4 of those pests every year and know them well.

Can anyone identify what pest this is from looking at the eggs and the damage on these 3 pics (click to enlarge)?

 

[Chuck]

This is just my opinion of what I have seen over the years and I have 3 possible theories. The first is the damage to the fruit was made by mice or rats, probably mice because of the size and shape of the damage. The eggs were laid later by some unknown moth. The second theory is tomato or tobacco hornworms. I have seen almost identical damage done to green tomatoes. Also hornworm moths lay their eggs singularly and not in clusters and they may lay 2 or 3 eggs on a single plant. The only thing wrong with this theory is that I have never heard of sphinx moths laying eggs or hornworms being on a cucurbit. The third and most likely is slugs. They do similar damage and the eggs look like slug eggs. The only downside to this theory is that AFAIK slugs lay their eggs in clusters and not singularly.

 

[Chuckers]

Yes, the multi-pest theory is something I was leaning towards. And although I never had rodents in my gardens before, I may have that year, and the damage certainly does look like rodent bite marks. And looking up pics of slug eggs, that seems like a very high possibility as they can be white, but unsure due to them not being in clusters.

I really don't think they are hornworms as my experience with insects is that they seem to always lay their eggs right on or very near the food source of the offspring.

 

[Chuck]

Yes, the multi-pest theory is something I was leaning towards. And although I never had rodents in my gardens before, I may have that year, and the damage certainly does look like rodent bite marks. And looking up pics of slug eggs, that seems like a very high possibility as they can be white, but unsure due to them not being in clusters.

I really don't think they are hornworms as my experience with insects is that they seem to always lay their eggs right on or very near the food source of the offspring.

And if were hornworms surely you would have seen damage to the leaves too.

 

[Chuckers]

Although it is somewhat possible that when I harvested the zuc the eggs were in clusters and most of the eggs fell off/stuck to the ground, but I don't think so - I would have noticed them on the ground. Because of the major pest issues the last 4-5 years, I am now very alert and aware of things like eggs & insect damage. I inspect my plants and veggies very closely, which makes gardening more of an evil chore than a hobby anymore.

 

[Chuckers]

And if were hornworms surely you would have seen damage to the leaves too.

Well actually, I had tomato hornworms one year and the only reason I even noticed them was because I happened to see one of them by sheer luck. I ended up finding 3 of them, and killing them, but they thankfully did hardly any damage to my plants. But I have seen pics and videos of how devastating then can be. Maybe I got them early? I dunno.

 

[Chuck]

Well actually, I had tomato hornworms one year and the only reason I even noticed them was because I happened to see one of them by sheer luck. I ended up finding 3 of them, and killing them, but they thankfully did hardly any damage to my plants. But I have seen pics and videos of how devastating then can be. Maybe I got them early? I dunno.

I get them every year but have learned what to look for when they are still very small. They are so well camouflaged the small ones are very difficult to spot. The easiest way is by seeing their feces on a leaf and then checking very closely above it. And in the early morning hours they will be on or very close to the tip of the limb or sucker. Sometimes it takes 2 or 3 days to find one though. A fully mature worm will completely defoliate a tomato plant in less than a week.