Diseases of Fruit Plantation Medicinal and Aromatic Crops

Anthracnose/bird eye spot disease

Causal Organism

• The anthracnose of grapes is caused by Gloeosporium ampelophagum (Pars.) Sacc. {Elsinoe amphelina (de bary) Shear –perfect stage}.
• Conidial stage is Sphaceloma ampelina de Bary . Conidia formed in pink acervuli and are hyaline, single celled, oblong or ovoid . Perithecia (Pseudothecia) are small and unconspicuous. Asci are globular where as ascospores are hyaline, 3-celled.
• The disease has been common in Europe since ancient times, however, in India, the disease was first recorded in 1903 near Poona and is now widely prevalent in Rajasthan, Uttar Pradesh, Punjab, Haryana, Andhra Pradesh, Karnataka and Tamil Nadu. Under north Indian conditions, the disease appears only during rainy season where as in the southern India, the berries escape infection as the crop matures before onset of the rains.
Symptoms

• The fungus attacks shoots, tendrils, petioles, leaves, stems and also the inflorescence and berries.
• Numerous spots occur on young shoots. These spots may unite to girdle the stem and cause death of the tips and may also cause die-back symptoms.
• Spots also appear on new shoots and fruits. Spots on petioles and leaves cause them to curl or become distorted.
• On berries, characteristic round, brown sunken spots resembling “Birds Eye” appear and hence the name of the disease.
• On leaves it appears as small, irregular, dark brown spots. The central tissue turn grey and falls. The disease appears as dark red spots on the berry.
• Later on these spots turn circular, sunken, ashy grey and surrounded by a dark margin which gives it the bird’s eye appearance.
• The spots are 7mm in dia but these may involve about half of the fruit.
 


Epidemiology

• The disease is severe during July- Aug and Nov- Dec months. Infection in new sprouts takes place during rainy season.
• Heavy rains after pruning leads to more incidence.

Mode of spread and survival

• The pathogen survives as dormant mycelium in the cankers on the stem and on infected twigs.
• Secondary spread is through conidia which are carried by wind and rain water.
Management
Cultural practices
• Training of vines should be done in a manner that water splashes should not reach the foliage, canes and branches during rainy season.
• Ground level canes and branches should be removed. All cankerous canes should be pruned and burnt to remove primary inoculum.
Chemical control
• Spray vineyards at the time of leaf emergence with Thiophanate methyl (0.1%), bitertanol (0.1%), benomyl (0.1%), carbendazim (0.1%), or Bordeaux mixture (1.0%).
• At least four sprays of fungicides should be given during rainy season at fortnightly intervals. Care should be taken not to spray the same fungicide regularly.
Varietal Resistance
• Verieties like Muscadine has been found to be immune, Champane as highly resistant, Concord moderately resistant and other varieties highly susceptible to the disease
• Variety Delight is tolerant whereas, Bharat Early and Hussaini are resistant