My blueberry plant after planting into the ground in March started showing the brown spots on its leaves. I had sprayed it with organic insecticide/ fungicide spray that time and pruned the plant to allow good air circulation. Nothing really changed. The new growth also started getting affected. I didn't notice any insects at that time. Suddenly today I saw these weird caterpillars on its leaves. At first they look like dried leaves but they are very ugly caterpillars. Also, the leaves had many brown eggs scattered throughout the leaves.
I have removed all the leaves of the plant and did massive pruning. Then I washed the plant with jet spray and sprayed it with spray.
Does anyone know what creatures are these? And can the plant be saved? Or do I have to remove the plant completely to prevent other plants from getting infected?

Welcome to NGA, @seedtotree .

Did you literally "remove all the leaves of the plant" ?

At any rate, I would just spray the plant(s) with Bt for the caterpillars.

It really doesn't help to remove the leaves to get rid of caterpillars. Bt is an organic solution that is safe to use on edible plants. You spray the leaves, then when the caterpillar eats a bit of the leaf that's been sprayed it gets sick and dies. Buy it as a concentrate at any garden center.

Removing the plant won't prevent the caterpillars from getting to your other plants. The 'mother' is a moth or butterfly and will lay eggs on whatever is a host plant. Obviously they like your blueberry.

It looks like a unicorn caterpillar, Schizura unicornis. According to my caterpillar book it eats apple, beech, birch, blueberry, cherry, dogwood, elm, hawthorn, hickory, hop, hornbeam, maple, New Jersey tea, ninebark, oak, persimmon, poplar, rose, sweet pepperbush, willow, witch hazel and some other woody plants/trees. Caterpillars only eat what suits their species, a caterpillar won't move to just any other plant.

The reason caterpillars are damaging to plants is that they remove leaves or parts of leaves which means the plants can't photosynthsize (make their own food) as much. Deliberately removing the leaves does even more damage in that way than the caterpillar may have done.

Thank you all for the information. You must have guessed that I'm a newbie. It looks like I was hasty to remove all the leaves. However the entire plant was covered with caterpillar eggs and scary caterpillars. Even the stems are looking dotted brown with the skin peeling off. I try to avoid any synthetic products in my garden. And previously organic sprays didn't work on this plant. I wonder if the plant has any other problem in addition to these caterpillars. Let me know your views.

Sooby thank you for giving more information about this particular caterpillar. It is good to know the caterpillars don't spread on their own.
But, how do I control moths. I see quiet a few of them in the garden nowadays. :(
I'll update you all with what happens next. I would hate to lose the plant.

We'd need to identify the moths to know if they are harmful ones. There's no need to control anything that isn't doing intolerable damage.

Are you sure the brown spots you are seeing are eggs and not just caterpillar poop? Caterpillars are messy critters that way!

I would venture to say that most of the moths/butterflies that you are seeing are not going to harm your garden plants (actually, none of the moths/butterflies will, but sometimes their babies are a bit annoying...). You obviously care about the environment, since you avoid using synthetic products, so getting an ID on your bugs before trying to eliminate them will just be another step in that process.

I have seen a black/grey colored moth near my citrus plants and white & yellow butterflies near vegetables. Sorry can't identify the species accurately but I believe they were caterpillars of cabbage moths I keep checking the leaves and remove before they hatch. This unicorn one was new to me.
Brown thing could be poop. Not sure. But I found eggs also on other plants.

If you have pictures you can post them here on NGA for identification. There is a forum for insect and bug identification or you can post them in this Ask a Question forum. Of course if you catch the caterpillar stage actually eating a plant then you know it's a pest but even then it's not always necessary to control them - it depends how much damage they are doing.