Rose Diseases

Are preventable.  Time of occurrence and prevention are listed below. For these diseases, see also the section on Spraying Recommendations.

1. BLACKSPOT -  A common problem with roses, it is a fungus disease that causes black spots on the foliage that cause the leaves to turn yellow and fall off.  Roses must be sprayed or Blackspot will be serious by mid summer.  Blackspot can not be cured, only prevented.  It is important to remove any infected leaves from the plant and the garden.  Throw them in the garbage, not the compost pile.  Spray with a recommended fungicide following label directions for Blackspot control.
2. POWDERY MILDEW - Mildew is also a fungus.  It grows over the upper leaf surface and is easily identified by the white powdery blotches it forms.  Severely infected leaves become brittle, wither and die.  Infected stem tissue has a withered and spindly appearance and is covered with white  powdery blotches. Powdery Mildew loves warm days and cool, dewy nights.

Rose Insects

For these insects, see also the section on Spraying Recommendations.

1. APHIDS - Aphids are brown or green insects that cluster on new and tender growth and suck plant juices.  That causes stunted growth and deformation.  They generally appear in early spring and summer.
2. RED SPIDER MITES - Minute pests that suck plant juices from the underside of the leaves.  This turns the leaves reddish-brown and dry.  They love hot, dry weather and multiply like mad.  Use your garden hose and a forceful spray on the underside of the leaves daily for 7 days when you see Red Spider Mites or their evidence.  This will interrupt their breeding cycle.
3. THRIPS - Thrip is a very tiny insect that is found in the base of the flower bloom.  It leaves the bloom speckled and deformed.  They appear in late June and stay the rest of the year.  Cut off and dispose of  the affected blooms.
4. BEETLES (JAPANESE) - Green and bronze, 3/8" flying beetle that makes its first appearance in the Erie-Niagara-Chautauqua counties in the beginning of July. They are initially attracted to light colored, fragrant rose blooms, but will eat anything when hungry, even privet hedges.  They stay till the second half of August. The warmer the temperature, the more active these beetles are.  They chew flowers, leaves and stems.  Looks like holes have been drilled in the bloom after they've been there.  The leaves look lacy after the beetles have fed on them.  Pick the beetles off and squash them, or knock them off the plant into a can of oil or sudsy water.  Using a beetle trap only attracts them to the area.
5. ROSE MIDGE - Suck the juices from the new buds turning the stem tips black, shriveled dry and burnt in appearance. MUST be prevented.


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