Q.Portulaca plants, denuding and tips of plants being eaten…
Can you help with what is causing the damage on my portulaca plants?
I’ve sprayed the plants with melathion, diazanon, I’ve also scattered snail & slug pellet amongst the plants. I’ve also set two rodent tramps in the area.
I’ve attached pictures for your review.
Any help would be greatly appreciated.
Thank you,

My guess is that a mammal has caused this damage, since rabbits and probably other mammals will eat this plant. Snails and slugs could also be the culprit, but if the slug pellets haven't worked, maybe that is less likely. Do check the area for slugs and snails and remove them by hand if you see them. Here is some advice for dealing with rabbits in the garden. There are also articles on mice, voles, and other mammalian pests on the website.
https://www.gardeningknowhow.com/plant-problems/pests/animals/keep-rabbits-out-of-gardens.htm