Downy mildew of Spinach and Baby Spinach

Initial symptoms of P. farinosa f.sp. spinaciae appear as slightly yellow, irregular chlorotic lesions on leaves. Lesions can expand, become necrotic and/or desiccate. Heavily infected leaves can appear curled and distorted. Under wet conditions or conditions of high relative humidity, sporangiophores and sporangia can be observed as a blue-grey mass on the underside of the leaf surface and occasionally on the upper leaf surface. Under conditions that are highly favourable for the fungus, sporulation can be observed in the absence of any distinct lesions. Lesions and sporulation can also be observed on the inflorescence of flowering spinach.