Put the salad in with him first thing in the morning and hold off on his bugs until later on in the day. He's more likely to start trying out the veggies when he's hungry.
If that doesn't work, you can also mix in bugs and worms with the salad - silkies work great because they hold onto the greens, so as your dragon picks out the worms, he also gets greens.
Try different coloured foods - my dragon was attracted to red sweet peppers, the yellows of grated squash, and the reddish colour of prickly pear.
Just a couple of tips to get you started
Now that your dragon is a year old, you'll want to gradually start cutting back on the number of bugs he gets each day until he's down to 25-50 bugs a week depending on which type of bug you use. You want to try and have him on the adult diet by the time he's 18 months old.