This is what we always called a tobacco worm. They like to eat tomatoes, as well as tobacco growing in the field. Yes, I was a country girl growing up on a farm raising tobacco, corn, beef cattle & very large vegetable gardens to feed a family of 12...there were 5 girls & 5 boys in my family.

The sphinx or hummingbird moth is the egg-laying culprit.

We call it the Tomato Horn Worm. Pick it off & squash it, feed it to chickens if you have them or put in soapy water.

If you don't kill it, it will defoliate your plants entirely. They are quite voracious eaters.

Kill that thing! It's not a good worm!

Oh my goodness! Thank goodness you discovered that little monster. You have one smart dog to stay away from it.

Last year they ate the foliage off the plants in my veggie garden and I was SO glad I had one tomato plant in one of those upside down planters on the deck, but no... they had even hatched there and were in the process of devouring that plant, too. I threw them two stories to the concrete drive. In Alabama we seem to get them in August. Dusting with Sevin dust MAY help, but the best thing is to watch vigilantly for them and then clear them off every day for a week or so.

Wow, that's a giant tomato lover. I'd kill it straight away as I suspect he only got to that size by eating every juicy leaf that he saw. Fortunately every thing in our country is smaller than in yours, except the price of fabric.

I'm going with Alien Invader...Yikes!!!

Oh dear that is sicking:(:(KILL IT!!!

It's a tomato worm. They get big and will devour the entire plant. Severen Dust. Will kill them/Lillian

That is one ugly bug.

Yup...tomato hornworm....and they can devour a lot in a little time! It's unbelievable how fast they grow also. One day they're not there and the next day they are as big as your fingers! I drown them in water...and then dump them on the lawn for birds and the local skunk to eat. And they really blend in with the plant too. Sometimes on the ground you will see a lot of poop that looks like a mouse did it. Then start looking up through the plant and you'll find those worms. They are sneaky!! I detest them!! Off with their heads!!!

If you have not seen them before you may be getting them from a neighbor or a newly acquired plant in your own yard. I would use the insect dust that won't harm humans or pets. Ask your local garden center if they have what you need to prevent the invasion.

Ugly bugger. Pull him off and step on him! Your tomato or his!! Kay

Glad you have found out what to do so that you can keep your foliage free from this voracious pest. Big enough I don't think I would want to step on him- Yuck, I would not handle the feeling of him squishing under foot eeewww , but I would not think twice of drowning him in soapy water and hope that you do not find more and no tell tail droppings either! Usually where there is one type of pest, there will be more, so unless this guy ate all the other eggs laid from the hummingbird moth that this one came from, I would be checking daily for awhile. Looks like he was planning on becoming one big moth himself! Now that I have visions of alien worms grown larger than I ever thought possible! Glad this bug is no more, good riddance and your shepherd was smart to say no way!

What a amazing & ugly caterpillar .As far as I know they aren't in Australia.Our tomatoes are usually attacked by fruit fly .

Oh I haven't seen one of these catapillars since I was a girl, we use to get them on our Acacia trees, they develop into lovely butterflies or is it moths..

It is a tomato horn worm... Nasty creatures that eat you goodies. Pick them off.!!

It is huge! I am so glad I have not seen one of those, although I believe I have lost a few tomatoes to a raccoon. I heard chittering one night and had to look online for a sound byte to confirm. Yep and they were loud! Here is a link to what raccoons sound like

Oh my, I've never seen one of those on our tomatoes! Thank you for sharing this picture.
Hugs, Lidia

I sure would hate to be a poor ole worm in your gardens ladies!!! Consider the lowly and, as you say, the ugly caterpillar. Not only does it have to be very lucky to get to be this mature, but has to know to spin a cocoon or go underground to change everything about itself. By this I mean change internal organs, grow wings and antennae and change into a moth in just a short time. Same thing happens with beautiful butterflies Truly a miracle. I wonder if tobacco and tomatoes were created to be their food. I would wish him a safe journey to the end of his life cycle----and to enjoy the tomato!!!

If only this worm would attack one small scrubby tomato...but NO !!....they eat a bite here...two bites there....here a tomato...there a leaf. They are voracious. BUT...there is a natural cure! If you happen to see this worm with tiny white eggs attached, it is the work of the Braconid Wasp. Leave that worm alone and the larvae of the wasp will take care of it and hatch more wasps. Look it up on the net...very interesting. Mother Nature wins again!!!! Never spray!

'What is this?' UGLY!!!!!! lol