Thanks ยายธี: I think we may have 2 kinds of aliens here. One (possibly a 'leaf curling spider') that makes a home by curling and gluing leaves and another (possibly a 'wooly aphid' -- insect) that sucks plant sap for food and may even kills young or small plants.

I found this http://homebuggarden.blogspot.com.au/2012/06/adven... and http://blogs.scientificamerican.com/running-ponies... and was told a mixture of 1 part cooking oil + 20 part water and a few drop of dish washing liquid (detergent), mix well and spray... can keep wooly aphids ... stationary...

Anyone knows something else? Please share!