Maybe this would be of some aid;
Cercospora leaf spot (Cercospora cannabis) symptoms
Mycosphaerellaceae
Kingdom: Fungi
Phylum: Ascomycota
Subphylum: Pezizomycotina
Class: Dothideomycetes
Subclass: Dothideomycetidae
Order: Capnodiales
Family: Mycosphaerellaceae
Cercospora leaf spot is a fungal disease caused by the pathogen Cercospora cannabis that affects cannabis plants. It is characterized by the appearance of small, circular, grayish spots on the leaves, which later turn brown and develop a yellow halo. Over time, the spots coalesce and cause extensive damage to the foliage, reducing the plant's photosynthetic capacity and affecting its overall health and productivity.
Cercospora leaf spot is a common disease in cannabis plants and can occur in both indoor and outdoor cultivation environments. The fungus can spread rapidly under warm and humid conditions and can be transmitted through spores that are dispersed by wind or water. The disease is more common in crowded and humid growing conditions, as it can quickly spread from plant to plant.
Preventing Cercospora leaf spot requires proper plant care and good hygiene practices. This includes maintaining good air circulation, avoiding overwatering, and keeping the grow environment clean and free from debris. Early detection and treatment are critical to prevent the spread of Cercospora leaf spot and limit its impact on cannabis plant health and productivity.
There are several treatment options available for controlling Cercospora leaf spot in cannabis plants. These include:
Fungicides: Applying a fungicide to the affected plants can help control the spread of the disease. However, it is important to select a fungicide that is labeled for use on cannabis plants, and to follow the label instructions carefully.
Cultural controls: Good cultural practices can help prevent the spread of Cercospora leaf spot. This includes removing infected leaves and debris from the growing area, ensuring proper air circulation, and avoiding overwatering.
Biological controls: Using beneficial microorganisms, such as Trichoderma, can help prevent the growth of Cercospora fungus and other harmful pathogens.
Resistance breeding: Some cannabis strains are naturally resistant to Cercospora leaf spot. Therefore, selecting resistant strains for cultivation can be an effective long-term strategy for preventing the disease.
Integrated pest management: Combining multiple control methods, such as cultural controls, biological controls, and resistance breeding.
It is important to note that early detection and prevention are key to controlling Cercospora leaf spot.
Below is an example of Cercospora leaf spot;