Q: What is causing the holes on my camellia leaves and buds of my camellia?
A: There are several possibilities. It could be the Cranberry rootworm beetles, Rhabdopterus picipes, or the Black vine weevil. Both of these insect adults feed mostly at night. Both have larval stages feed on roots during part of their life cycle. They prefer to feed on berry crops, grapes, cane fruit, ornamentals and leafy vegetables.
The Cranberry adult beetle feeds on new growth of azaleas, camellia, red tip photinia, and other shrubs in the landscape. They leave characteristic holes in the leaves which are narrow and straight or crescent-shaped. The new growth is the part of the plant most damaged by this pest so only the new growth would typically be treated with insecticide. Fortunately, these insects vary from year to year in their abundance so fewer may be seen next year which will mean less damage. For the average homeowner, it is only a cosmetic issue and probably doesn’t require treatment.
The Black vine weevil can be found throughout North America and can cause extensive damage in the warmer regions. They overwinter in the grub stage in the soil. In the spring they wake up when the soil warms and they begin to feed. When they are fully grown they burrow deeper in the soil and pupate. The adults hatch in 2-3 weeks. Adults lay their eggs near the base of the host plants late summer and the cycle continues until the weather becomes cooler. Adults feed on the leaves making large notch like holes. Plants which have large numbers of grubs feeding on them can eventually die.
Adult control is best done by using sticky traps. Place the traps on the ground and shake the limbs of the shrub or tree. The insects will fall to the ground and get stuck in the traps. Dig lightly around the soil if you see vine weevils and pick out the small grubs. Drop them in hot soapy water. Vine weevils hide in garden debris during the day so it is a good idea to keep your garden clean and free of leaf and twig litter. Bt used correctly will kill the grubs in the soil. Remember to follow the directions on the label.