Phomopsis blight



Phomopsis blight is caused by a number of plant pathogens of the Phomopsis genus. Symptoms vary depending on the strain of disease and variety of plant infected.

Important species
Important species susceptible to phomopsis blight:
 * Asparagus (Phomopsis asparagi, Phomopsis asparagicola, Phomopsis javanica)
 * Aubergine (Phomopsis vexans)
 * Cucurbits purple stem (Phomopsis cucurbitae) black stem (Phomopsis sclerotioides)
 * Grape cane and leaf spot (Phomopsis viticota)
 * Strawberry leaf blight (Phomopsis obscurans)

Aubergine
Leaf spots first appear as small (less than 0.4 inches) gray to brown lesions with light centers. Lesions often become numerous and cover large areas of leaves. Severely infected leaves become torn, yellow and wither. Small black dots, the fungal fruiting bodies called pycnidia, are often apparent on older leaf, stem, and fruit lesions. Stems and branches may develop dry, brown, cracked and sunken cankers. If a canker develops at the base of a stem, it can girdle and kill the stem. Fruit lesions are sunken, discolored, and soft with a surrounding margin of black fruit bodies. If conditions become dry, infected fruit become shriveled, dry, and form black mummies.

Biological
No biological control strategies have been developed for Phomopsis blight.

Chemical
If disease is identified in the field treatment with a recommend fungicide is advisable. Newer fungicides such as Cabrio, Quadris, and Endura are registered for use on aubergine, but their efficacy against Phomopsis fruit rot is unknown. Fungicides are most effective when combined with cultural control strategies.

Prevention
Plant only high quality seed and transplants free from the Phomopsis blight fungus. Plant resistant varieties if available and suitable for your marketing needs. Practice a three-year or longer crop rotation between crops. Destroy crop residues after harvest by deep plowing to reduce over wintering of the pathogen. Promote rapid leaf drying by timing irrigations to end before dusk, spacing plants farther apart in and between rows, and planting parallel to the prevailing wind direction.