Chrysanthemum plants are susceptible to various types of fungal, bacterial, and viral plant pathogens. Among them, fungal leaf spot disease is the major economic important disease of Chrysanthemum. In this post, we will discuss causes of chrysanthemum leaf spot/ blight disease, symptoms, chemical control, and organic control of chrysanthemum leaf spot/ blight disease
Cause of Chrysanthemum leaf spot disease
The disease is caused by various fungal pathogens viz., Septoria chrysanthemi, Septoria chrysanthemella, Alternaria species, and Cercospora chrysanthemi.
Symptoms of Chrysanthemum leaf spot/ blight disease
They initially appear as yellow spots that turn brown to black in later stages. The spots often occur on lower leaves first and coalesce into large necrotic areas and finally death of the entire leaf causing blight symptoms. Small black fruiting bodies are also seen on the lesions of some leaf spot fungi. Leaf spot diseases are favored by prolonged periods of leaf wetness and high atmospheric relative humidity.
Cultural control of Chrysanthemum leaf spot/ blight disease
- Maintain proper sanitation in the chrysanthemum fields.
- Rogue out and destroy the infested plants away from the main field.
- Avoid overhead sprinkler irrigation methods.
Organic control of Chrysanthemum leaf spot/ blight disease
- Spray bio fungicides such as Trichoderma @5-10 ml/ lt water.
Chemical control of Chrysanthemum leaf spot/ blight disease:
Spray any of the following fungicides at weekly or 15 days intervals
- Azoxystrobin 23% SC @ 1ml/ lt water,
- Azoxystrobin 4.8% w/w + Chlorothalonil 40% w/w SC @ 1.5 ml/lt water.
- Chlorothalonil 75% WP @ 1.5 ml/lt water.
- Copper Oxychloride 50% WG @ 2.5gm/lt water.
- Copper oxychloride 50% WP @ 2.5gm/lt water.
- Fludioxonil @1ml/lt water,
- Mancozeb 35% SC @5ml/lt water
- Mancozeb 75% WG @ 2.5 gm/lt water.
- Myclobutanil 10% WP @ 0.4gm/lt water.
- Propiconazole 25% EC @1gm/lt water.
- Thiophanate Methyl 70% WP @1gm/lt water.
This is all about Chrysanthemum leaf spot/ blight disease chemical and organic management control practices. If you have any other queries regarding the plant disease organic and chemical control, comment below.