Little Holes and White Bugs on the Leaves of Roses
- Rose aphids are tiny white insects with slightly oval and flattened bodies. Aphids punch tiny holes in leaves as they feed on the sap inside. They can cause stippling and distortion of young leaves and flower buds. In small numbers, aphids are usually nothing to worry about, but large numbers can be devastating. Natural controls include lady beetles, soldier beetles and syrphid flies. Regularly knocking aphids off plants with a spray of water in the mornings can also help keep their numbers in check.
- Soft and gray-bodied mealybugs are usually covered in a cottony white wax that gives them the appearance of tiny cotton balls. Mealybugs congregate in masses and feed on leaves and buds and can cause them to die and drop off plants. They don't necessarily cause holes, but they can cause serious damage to foliage. Insecticides are not generally effective against mealybugs, according to the University of California, but insecticidal soaps and oils can help managing populations. Also, a simple jet of water from the hose can keep mealybugs in check.
- These caterpillars will certainly chew holes in rose leaves. They are about an inch long and have a furry, white body. The hairs that cover puss caterpillars contain venom, so never remove them from plants by hand without gloves. Insecticidal sprays containing Bacillus thuringiensis are effective, as are insecticidal oils like neem oil. Applying granular disulfoton to the soil around your roses will provide the longest lasting control.
- The rose slug is the larval form of the sawfly. It is black to very pale green and chews holes in foliage. They do have many natural enemies, which keep populations in check, but if you need to control them, a strong jet of water from a hose will work. Insecticidal soap or spinosad will also kill rose slugs.