Septoria Leaf Spot

Septoria spp.

General Symptoms

Septoria symptoms can vary between plants, but generally begin as small dark leaf spots that grow and spread. Spots have reddish-brown margins and tawny light brown to pale grey coloured centres. The spots may join up to form large blotches. Fungus fruiting bodies may be visible as small black dots on the spots.

Tomato Symptoms of Septoria lycopersici

In midsummer during rainy periods, numerous small dark spots appear on the lower leaves and spread upwards, towards the new growth. Spots can develop light brownish centres. Black specks (these are the fruiting bodies, or 'pycnidia' of the fungus) may be visible in the spots. The spots can expand and if they’re left untreated, cause leaves to yellow, wither and drop off.

Tomato fruit don’t show symptoms (black spots on tomato fruits are caused by anthracnose). Although the fruits of affected plants remain edible, the disease severely weakens tomato plants, so fruit quality and quantity may be compromised.

Lesions on a passionfruit leaf, showing the 'pycnidia' fungal fruiting bodies

 Passionfruit Symptoms of Septoria passifloricola

Symptoms begin with small, light brown spots stippling passionfruit leaves, stems and fruit. Spots can also be surrounded with brown rings (halos) of dead tissue. Tiny black dots (fungal fruiting bodies, that produce spores) may be visible on the spots. 

On fruits, Septoria spots develop into larger patches, eventually covering most of the surface area. Symptoms on fruits can look very similar to brown spot (Alternaria passiflorae), but Septoria spots aren’t as sunken-looking or wrinkly as Alternaria spots. Although affected passionfruit pulp remains edible, it may ripen unevenly. 

To control leaf spot, apply Yates Nature's Way Fungus Spray at 10-14 day intervals.

 Celery Symptoms of Septoria apiicola

Small brown spots begin on the outermost lower leaves, then spread to the rest of the plant, including the stems. The spots can combine and enlarge, causing entire leaves to collapse and wither.

How to Protect Your Plants

Remove all diseased plants. Practice crop rotation, avoiding planting in the same spot for 3-4 years. Avoid overhead watering and ensure there’s enough spacing between plants. Treat the disease with a suitable fungicide as soon as you see it, then continue to repeat treatments regularly, while conditions remain moist and humid.

• Vegetables, including Tomato, Lettuce and Celery: apply Yates Copper Oxychloride as a preventative barrier, at 14 day intervals.
• Passionfruit and Citrus: apply Yates Nature's Way Fungus Spray at 10-14 day intervals.
• Ornamental plants, including Chrysanthemum and Gerbera: apply Yates Liquid Copper Fungicide at first sign of disease and repeat every 10 -14 days as required.

Lesions on a celery leaf, showing the 'pycnidia' fungus fruiting bodies

Plants Impacted:

• Tomato
• Citrus
• Passionfruit
• Celery
• Lettuce
• Blackcurrant
• Chrysanthemum
• Gerbera