g'day richard,

most likely snails, also look for dendrobium beetles.

for the snails if they are crawling up to the plants then place beer
traps around the base of where the plants are. also something new a
dose of strong made instant coffee sprayed onto the plants is the
latest in snail deterring methods, supposed to kill them

or do a night time torch safari and pick them.

len

snipped
--
happy gardening
'it works for me it could work for you,'

"in the end ya' gotta do what ya' gotta do" but consider others and the environment
http://hub.dataline.net.au/~gardnlen/