|
|
Black spot (fungus) |
General and serious. Leaves have black spots with irregular margins. Leaflets yellow and drop off. |
If problem is serious and recurrent yearly, consider planting resistant varieties. Collect and remove fallen leaves. Susceptible varieties must be protected with fungicides before disease is present for good control. Begin applying fungicide in spring as leaves expand. Continue at 10- to 14-day intervals. Use azoxystrobin, coppers, chlorothalonil, fenarimol, mancozeb, maneb, myclobutanil, neem oil, propiconizole, sulfur, thiophanate-methy or triforine. |
|
|
Cankers of canes (fungus) |
Girdling cankers on canes. |
Prune diseased and dead canes. Avoid spring pruning until after danger of freeze injury is past. |
|
|
Powdery mildew (fungus) |
Whitish patches on leaves. Seldom a problem, except on miniature roses. |
Start fungicide applications in spring as leaves expand. Continue at 10- to 14-day intervals. Use fenarimol, propiconizole, sulfur, thiophanate-methyl, thiophanate-methyl plus mancozeb, triadimefon, triflumizole or triforine. Resistant varieties are available. |
|
| University Outreach and Extension does not endorse commercial products. Follow the label on all pesticides. |
