پزشکان گیاهان

Fungicides registered for black spot control should be applied preventatively to susceptible roses starting in spring before the new leaves become spotted. From this time through frost, the plants should never pass through a rainy period without a protective coating of fungicide on the leaves. Fungicides registered for black spot control include propiconazole (e.g. Banner), thiophanane methyl (e.g. Cleary 3336), chlorothalonil (e.g. Daconil 2787), mancozeb (e.g. Fore, Dithane, or Maneb), thiophanate methyl + mancozeb (e.g. Zyban), trifloxystrobin (e.g. Compass) and myclobutanil (e.g. Systhane). Most of these fungicides can be sprayed at 7-10 day intervals when rains are infrequent. During rainy weather, it may be necessary to spray the plants more frequently. Details on rates and timing of application can be found the current Virginia Pest Management Guide for Home Grounds and Animals (VCE Publication 456-018) or the Virginia Pest Management Guide for Horticultural and Forest Crops (VCE Publication 456-017), http://www.ext.vt.edu/pubs/pmg/. For information on the proper use of pesticides and fungicides, refer to any current VCE pest management guide