Jul 13, 2023 · Rhubarb leaf spot is a common fungal disease caused by the fungi Mycosphaerella pontederiae and Ramularia rhei. It primarily affects the leaves of the rhubarb plant. Symptoms: Infected leaves develop small reddish-brown spots that gradually enlarge over time.

Nov 29, 2022 · Ascochyta leaf spot is first seen as small, greenish-yellow blotches, less than ½ inch (1 cm.) across, on the upper surface of the leaves. Gradually, the blotches develop white centers surrounded by a reddish border further bordered by a grayish-green area.

Ascochyta leaf spot - leaf infection first appears as small, green-yellow, irregular spots less than one half inch in diameter on the upper leaf surface. The leaf develops a mosaic appearance as the lesions unite.

Jul 2, 2008 · The best way to control leaf spot is to remove all infected leaves as soon as you notice the blemishes (do not throw them in a compost).

Jul 23, 2021 · By understanding the causes and symptoms of these diseases, as well as implementing proper cultural practices, you can prevent and treat rhubarb leaf spots and ensure a healthy and productive rhubarb harvest.

Leaf Spot. These fungi cause circular, or angular spots, variable in size having beige centers surrounded by a red zone. When affected tissue dies, it may drop out, leaving large ragged holes in the foliage. Fungi overwinter in infected plant debris …

Leaf spots are common on field-grown rhubarb west of the Cascade Range due to frequent rains in March and April when leaves and stalks are actively growing. Both pathogens produce spores that move by wind and splashing water. Ramularia …

Jun 29, 2023 · Leaf Spot: Leaf spot is characterized by dark brown or black spots on the leaves of the plant. These spots may enlarge over time and cause defoliation. Crown Rot: Crown rot affects the crown and roots of the rhubarb plant, causing wilting, yellowing leaves, and …

May 16, 2023 · Rhubarb Leaf Spot: Leaf spot is a common foliar disease in rhubarb plants, caused by fungal pathogens such as Septoria spp. and Colletotrichum spp. It appears as small, circular spots on the leaves that gradually expand and develop a dark brown or purple color.

This fungal disease is called “leaf spot” because it starts by affecting the leaves. But ramularia will quickly spread to the stalks as well. As with ascochyta leaf spot, ramularia starts with quickly growing spots on affected leaves.