A Gardeners Forum Forums General Discussion Plant pests and problems Pests on Rose Bushes

I bought two new rose bushes from a store and planted them over a week ago. They have been doing all right, except I noticed a folded leaf on the John F. Kennedy rose. When I peeled it open, there was a green worm barely a half-inch long wiggling around on the inside! I immediately plucked the leaf and threw it away. That was a few days ago.

Today, when I was spraying down my roses to treat for blackspot, I noticed a folded leaf on another of the new roses (an Irish Gold). When I peeled it open, I saw strands like a spiderweb, but no worm. I plucked it off and tossed it. I checked on my JFK and saw no folded leaves but a lot of the leaves near the bottom of the plant have turned bright yellow! It's the only one doing that and wasn't doing that on Saturday, so it must have just done that either yesterday or today.

Anyone have any idea what could be going on? I plan on buying some pesticide when I can afford to but I want to know exactly what is happening so I know what I should buy.

I think your plant is affected by Powdery mildew.It is a fungus disease that affects young leaves, causing them to curl and twist and develop a purple coloration. As the disease progresses, leaves become covered with white powdery fuzz. Whereas blackspot is usually most severe on the lower part of the plant, mildew affects the top part of the plant. Mature leaves are less likely to be affected. Mildew is spread by wind and develops rapidly during periods of warm, dry days followed by cool, humid nights. Infections of mildew are actually discouraged by the presence of water on the leaves. However, keeping plants wet all night to avoid mildew provides an environment that allows other diseases to develop. Infection can be reduced through sanitation and fungicide spray programs. Prune out all dead and diseased canes to reduce initial fungus infection. Because new growth is especially susceptible, thorough coverage of new growth with fungicide is important. Plant roses in areas where they receive good air circulation and where the foliage can dry off rapidly in the early morning to prevent many types of diseases.