There is a bad side to the rainy season and that is fungus diseases of roses. Our beloved roses are susceptible to several types of fungi. Botritus, also known as grey mold, is shown in today’s photos.
During the growing season, the disease affects rose buds and petals – you may see spotted flower petals or the tips and edges of the petals turn soft and brown. The spots look like water spots on the petals, however, the spots are actually caused by the plants’ reaction to the invasion of the fungus at the spot where the petal has been damp. Other times, the flowers simply fail to open, or result in a shattered mess of brown petals. This can be followed by wooly gray fungal spores on decaying tissue. The brown rot is botritus. I will remove as much as possible then spray with a combination of lime sulfur and horticultural oil to kill any spores and to discourage spores from wintering over.