Phomopsis obscurans
Encyclopedia
Phomopsis obscurans is a common disease-causing fungus
affecting strawberry
plants. Although the fungus infects leaves early in the growing season, leaf blight symptoms are most apparent on older leaves near or after harvest. The disease can weaken strawberry plants through the destruction of older foliage. Weakened plants can result in reduced yields the following year. In years highly favorable for disease development, leaf blight can cause defoliation and, in some cases, death of plants.
The fungus can also cause a fruit rot called soft rot, especially in warmer climates, which can result in serious losses.
trusses and petiole
s may become infected which may girdle and kill the stem
.
V-shaped lesion on a strawberry leaf
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
affecting strawberry
Strawberry
Fragaria is a genus of flowering plants in the rose family, Rosaceae, commonly known as strawberries for their edible fruits. Although it is commonly thought that strawberries get their name from straw being used as a mulch in cultivating the plants, the etymology of the word is uncertain. There...
plants. Although the fungus infects leaves early in the growing season, leaf blight symptoms are most apparent on older leaves near or after harvest. The disease can weaken strawberry plants through the destruction of older foliage. Weakened plants can result in reduced yields the following year. In years highly favorable for disease development, leaf blight can cause defoliation and, in some cases, death of plants.
The fungus can also cause a fruit rot called soft rot, especially in warmer climates, which can result in serious losses.
Symptoms
Symptoms of leaf blight infections begin as one to several circular reddish-purple spots on a leaflet. Spots enlarge to V-shaped lesions with a light brown inner zone and dark brown outer zone. Lesions follow major veins progressing inward. The whole leaflet may turn brown. In severe cases, stolons, fruitFruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
trusses and petiole
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
s may become infected which may girdle and kill the stem
Plant stem
A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...
.
Prevention and control
There are no varieties with reported resistance to leaf blight but these cultural practices should help reduce infection:- Remove the older and infected leaves from runner plants before setting.
- Take care in spacing runner plants in matted-row culture.
- Plant in light, well-drained soil in a location exposed to all-day sun and good air circulation.
- Control weeds in the planting. Weeds reduce air circulation and increase drying time for leaves. (Leaves stay wet longer in weedy plantings.)
- Removing infected leaves after harvest (during renovation) is helpful in reducing inoculum and controlling leaf diseases.
V-shaped lesion on a strawberry leaf