Cosmetic Flower Damage

• Many insects rely on the flower of the rose plant as a food source. Popillia japonica, or the Japanese beetle, causes cosmetic damage to roses. These insects eat large round holes in the flowers of the rose, particularly in paler-colored rose blooms. Two kinds of thrips, both Anaphothrips obscurus and Frankliniella tritici, suck the sap out of young buds. Rose maggots eat the young buds in early spring. Rose weevils lay their eggs in rose hips, who then feed on the reproductive parts of the rose as they grow. Adult rose weevils then eat the rose bloom, leaving small holes drilled into the petals.
  
  

Cosmetic Leaf Damage

• Other insects neglect the flower while eating rose foliage. The rose leafhopper feeds on the chlorophyll and sap present in rose leaves, causing leaves to turn brown or yellow and curl inward. The bristly roseslug, curled rose sawfly and roseslug devour leaves during their larval stage. Spittle bugs create foamy nests in the stems and leaves of rose bushes for several weeks during the nymph stage, but rose plants recover quickly once the insects develop into adults. Leaf cutter bees cut semicircular holes in rose leaves, but the damage rarely hurts the health or future growth of the plant.
  
  

Severe Tissue Damage

• Many insects puncture the soft tissues of leaves, stems or flowers and suck out the sap or moisture from the rose bush. This type of damage can seriously harm roses by preventing new growth. Plant lice, or Macrosiphum rosae, can kill a young rose plant through this feeding method. In addition, many sucking insects leave behind a waste product that attracts mold, fungus and ants. Sawfly and carpenter bees lay eggs on the ends of pruned rose stems. The larvae tunnels into the stem, eating tissue and killing the rose at it progresses.
  
  

Prevention/Solution

• Rose gardeners can use integrated pest management, or IPM, to help manage insect damage. According to the U.S. Environmental Protection Agency, IPM guides gardeners in evaluating the situation and choosing a solution that poses minimal risk to the environment and people in a cost-effective way. Prevention methods include minimizing characteristics of the garden that encourage pests and choosing insect-resistant species. Planting catnip or geraniums near rose bushes discourages the presence of insects such as the Japanese beetle. IPM solutions ask the gardener to consider the least risky solutions first. Rose gardeners can remove larger insects by hand and drown the pests in soapy water. A hard jet of water sprayed from a garden hose often dislodges smaller insects from rose bushes. Ladybugs and nematodes eat insects such as thrips, aphids and beetles. When all else fail, commercial insecticidal soaps and insecticides target and kill the insects that damage roses.