Rose bushes are susceptible to many insects, so when you notice damage to flowers or foliage, identify the invaders. Many can be removed by hand or with a strong jet of water from a hose. For severe infestations of multiple pests, rosarians may consider a systemic control. Handle with care: Insecticidal chemicals are toxic not just to pests but to beneficial insects like bees, as well as to humans.
Integrated Pest Management (IPM) is a hybrid solution to organic and chemical spray control of rose pests. It starts with the least harmful method of control for wildlife, man and the environment. Gardeners are urged to tolerate some natural damage since beneficial insects mix with destructive pests and both are killed.
Learn to identify the insects invading your roses. If there are only a few insects of one type, pick them off and remove any affected leaves to destroy eggs or larvae. Wash large infestations off rose bushes with soapy water or a stream of water from your garden hose.
Biological controls such as ladybugs to control aphids are effective and non-toxic. Natural controls including pyrethrins and sex pheromones that lure pests to control materials are effective. Toxic chemicals, either contact or systemic, are the final step to be used in severe infestations of multiple pests only until such pests are brought under control.
When you water your rose bush, the systemic is absorbed by the roots and is carried throughout the plant. Some systemics combine fertilizer with insecticide. This produces a healthy rose and a barrier against harmful insects like aphids, birch leafminers, lacebugs, spider mites, thrips and whiteflies.
Systemic insecticides are blind: They kill beneficial insects and wildlife as well as pests. They have been linked to the collapse of bee hives and colonies when drones are exposed to the toxins and carry them back to the hive. They are also suspected in the reduction of songbirds who depend on rose hips for winter feed.
Systemics are a hazard to humans and animals. Keep them out of the reach of small children and animals. The chemicals can be fatal if swallowed. Wash hands after handling and do not inhale fumes. Do not allow residue in rinse water to spread to ponds, rivers or lakes. Follow label instructions carefully to protect your own health and the environment.