**3. Diseases of vegetables**

172 Fungicides for Plant and Animal Diseases

Fig. 4. Light microscope photographs of *Diplocarpon rosae* growing on artificial malt agar medium: (A) *D. rosae* two-celled conidial structures before and during germination.

Control practices start with planting resistant rose varieties where available. Good sanitation is key to keeping the rose disease free. Recommended cultural practices are: All infected debris should be collected and burnt or buried; all infected canes must be pruned; overhead irrigation must be avoided because it tends to splash conidia from infected to non-infected parts of the plants. It recommended to water plants at the base; the plants should be preferably watered in the morning as opposed to the evening, because the conidia require several hours of wetness to cause infection, therefore watering in the morning reduces the hours of leaf wetness. In addition, plants should be well spaced and kept weed free to allow for aeration. Furthermore, one must avoid planting susceptible plants under the shade. When blackspot disease is establish, its control relies heavily on fungicides. In Table 1, the

Mode of Action Target site and code Group name Chemical group Common name FRAC\*

Triazoles

Thiophanates

**DMI**-fungicides (**D**e**M**ethylation **I**nhibitors) (SBI: Class I)

**DMI**-fungicides (**D**e**M**ethylation **I**nhibitors) (SBI: Class I)

**MBC**-Fungicides (**M**ethyl **B**enzimidazole **C**arbamates)

Table 1. Fungicides labeled for the control of powdery mildew on roses.

activity Inorganic Inorganic Copper

contact activity Inorganic Inorganic Sulphur M2

code

3

1

Myclobutanil (Immunox) Propiconazole (Banner Maxx) tebuconazole

Thiophanatemethyl 3336 4.5 F 3336 50W Halt

(different salts) M1

Piperazines Triforine 3

(B) Three day-old conidium germination. (Courtesy of E. W. Gachomo).

fungicides recommended in blacksopt disease management are listed.

C14-Demethylase in sterol biosynthesis *(erg11/cyp51)*

C14-Demethylase in sterol biosynthesis *(erg11/cyp51)*

ß-tubuline assembly in mitosis

multi-site

multi-site contact

\*FRAC (Fungicides Resistance Action Committee)

**2.6.2 Control of blackspot disease** 

sterol biosynthesis in membranes

sterol biosynthesis in membranes

mitosis and cell division

activity

activity

Multi-site contact

Multi-site contact
