As the temperature and humidity rises here on the Coffs Coast foliage diseases start to appear. The trick is to try and catch them before they take hold and set your plants back on their heels!
Get into the habit of walking around every few days to remove anything that looks a bit dodgy, spotty or weird – these are usually found on the older leaves and toss them into your general waste bin – not into compost bins. This not only keeps things looking tidy but it also eliminates a major source of fungal spores that would otherwise spread. Avoid wetting the foliage when watering as this splashes spores about the creates ideal conditions for foliage diseases to flourish.
If disease is getting away from you – despite your best efforts to remove damaged material, consider applying an organic fungicide to the remaining healthy unaffected foliage to help contain outbreaks. Fungicides add a layer of protection to the leaf, preventing fungal spores from germinating. Copper hydroxide can be applied to tomatoes to assist in managing septoria leaf spot. Organic products based on potassium bicarbonate effectively shield zucchini foliage from powdery mildew and kill existing fungal spores as well. Reapply fungicides after rain and always follow directions on the product label.