Got a strange caterpillar in the garden at the moment. About 3 inches long, black back and light brown underneath. Has two obviously false eyes on the head and acouple of fine lines of white dots down each side where the black color meets the brown. It's also got a funny little orange spur like thing sticking out from it's back at the rear end.

Will try to post photo soon.

In the meantime does anyyone know from the description what it is.

See photo.

Closest I can find anywhere is this photo that I am taking to be the same caterpillar but in a previous state and is now going through some sort of change.

I don't know the ID, but if you really need to know, contact Pisuth Ek-Amnuay the author of the Thai book (with some English) 'Plant Diseases and Insect Pests of Economic Importance' Send photo and description (caterpillar, pupal case and adult moth, and host plant that you found it on, if possible) to: insectzoos at hotmaill dot com

BTW: I'm not an entomologist like Khun Pitsuth, but here's some basic biology for your information: "Some sort of change" that you observed should by now be obvious, it is one step in the four part life cycle of an insect with complete metamorphosis (like a moth), the caterpillar stage feeds on the plant, completes its cycle and then changes into the pupa stage, characterized by a chrysallis or coccoon, from which emerges the adult moth which then mates and lays eggs that hatch into the larva stage (caterpillar).

Identification is best achieved if you can observe the adult insect. Pest control is best achieved by targeting the larval stage when the caterpillar is just beginning to feed. Birds, bats, wasps and other pest predators may do the job for you, if not, choose least toxic options so as not to kill off the natural controls. Tolerance of some minimal damage should be allowed if possible. If the damage is not tolerable for econonmic or aesthetic reasons: Hand pick or hose off caterpillars if possible, choice of sprays should consider biological control like BT (bacillus thurengensi), botanical insecticides with minimal residual effects on other organisms, neem oil products that repel and disrupt reproduction. Avoid broad spectrum insecticides. Read about Integrated Pest Management www.ipm.ucdavis.edu and other sites. Check out the TV Farming in Thailand forum and the organic subforum for more informaton.

Prevent or minimize pest problems with proper growing conditions, including plant selection - right plant in the right place, good soil fertility, preferably based on a soil test and site specific, deficiency specific amendments. Fertilze moderately, overuse of general purpose high nitrogen fertilizers can increase plant susceptibility to pest and disease problems. Water appropriately, not too much or too little, (a moisture meter is invaluable especially for potted plants).