Can You Help Me To Identify This Pest?

A pest is destroying my garden again. Can you help me to identify it, so I will at least have a chance to fight it and prevent that my gardening season will be over before it has started?

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Killer Pest

I had a troublesome gardening season last year. I didn't recover from the back surgery as quickly as I had hoped and had to ask others to take care of my crops most of the time. I hated the fact that I had to miss out on all the fun.

To top it off, my crops got infected by a pest. It started at one end of my garden, but quickly spread to all corners, infecting everything it came across. No matter which kind of crop it was, it got infected: pumpkins, melons, Chinese Artichokes, Yacon, Chayote, Jerusalem Artichokes, lettuce, sweet potatoes, ....
Surprisingly, my tomato plants were the last ones standing. But they too had to give up.

Early September, my gardening season was over. There wasn't a single crop left.

Hope And Action

I never found out what killed all my crops. Some people suggested it might have been caused by the extreme drought we experienced last summer. Up until today, I held on to that thought.

Just to be sure, I cleaned and disinfected everything: my trellises, both my greenhouses, my tools. If it had been a pest, I definitely didn't want it to return. I made sure all wires I had used were removed, and even all leftover tendrils that had clung to the climbing racks were removed.

Just in case...

The Pest Is Back

Due to circumstances, I only started to prep the garden sometime last week. Of course, I already had loads of seedlings impatiently waiting inside the house, but I didn't bring them to the greenhouse to harden them off - mainly because it had been really cold during the last couple of weeks.

I must admit I was a little paranoid, too. Every spot on a leaf I detected made me worried.

Today, it appears my paranoia wasn't as irrational as I had hoped...

I had seen some strange spots on a couple of plants, but warned myself to not get worked up about it - maybe it was nothing. After all, nature is not perfect, right?!

Yesterday, I noticed that the spots on my two little melon plants were really looking suspicious. This morning, they still looked the same. But by the time it was starting to get dark, I went outside to bring the tender plants inside (the night are still very cold). And this is what I found:

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The container they were planted in was - just like the soil - fresh and brand new. This is, without any doubt, the same pest that hit my garden last year.

If only I knew what it was, then maybe I could do something against it. But as long as I can't identify it, there is nothing more I can do than whatever I've already done.

I went into the big greenhouse, which is placed about 10 meters from the small one where the melons stood in their little container, waiting for the right time to be planted into the soil. I had noticed a couple of days earlier the one tomato plant wasn't looking very healthy. But it had gotten worse overnight.

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On my beautiful kiwiberry plant, I found a couple of leaves that looked like this:

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I don't even know if this is the result of an infection by the same pest or not.

Ideas?

Is there someone who can help me to identify this pest?

Your guess is as good as mine - I simply don't have a clue.

If I can't find out, I don't see the use of continuing to prep the garden, because I already know how this will end - and it is not pretty, that's something I can assure you. I've seen it happen last year.

I can't even imagine what it would be like to go through summer without my fruits and veggies. The garden is normally the only place I can fully relax, I don't want to give it up.

So, if you have any idea, I'd be very grateful if you'd share it with me, so i can look into it further.

Please help me to identify this pest.