Australian weevils are a small beetle with a distinctive long snout. They stay in the ground during the day and climb up the stem to the new growth at night.
The adults drill small round holes deep into the flower buds and hips for feeding and egg-laying. Eggs are usually laid in the hip or ovary and the small white larvae feed on the reproductive parts.
The greatest damage to roses is cause when adults feed on flower buds. The adult punctures the floral parts contained inside buds. Later, if the flowers succeed in opening, these flower parts are riddled with holes, resulting in ragged, unsightly blossoms.
If flower buds are not plentiful, the adult beetle may feed on the tips of new rose shoots, causing the death of terminals. At other times it gouges the stems of buds, causing the bud to wilt and die.
The best method of eliminating these is going out at night with a torch and picking them off and squashing them.
Alternatively try using a garlic spray. Take two teaspoons of crushed garlic and put into 500mls of water. Let this sit for a couple of days so the water is very potent. Strain and spray onto the plants.
For bad problems use an insecticide from the garden centers.