- The scientific name : Stone fruit rust
- The causative fungus : Tranzschelia discolor Tranz . et Litv
and Tranzschelia pruni-spinosae Diet.
- Symptoms of the disease :
- Rusty brown pustules appear as small circular to pale yellow, angular spots on both surfaces of leaves.
- The spots on the lower leaf surface developed rusty brown blisters
- Leaves bearing rust pustules turn yellow or red, resulting in severe defoliation
- The branches show symptoms in the form of mild swelling.
- On the lower surface are the uridine spores, carried on short stalks, interspersed with hyaline-headed hemispheres and light brown in color, obovate to interconnected in shape.
- The causes of disease :
- The host requires warm and humid conditions for periods long enough to develop (ideal temperatures (15-24°C). Spores will not germinate when temperatures are above 30°C or in the absence of moisture)
- Conditions suitable for the spread of infection are more dangerous for early varieties
- It is spread by wind or rain spray from infected leaves from the previous season that remained attached to the tree over the winter
- Disease development cycle :
The fungus that causes long-rotating rusts is bi-host, and its alternate host is the anemone plant.
- The disease is renewed annually by uremic spores found on infected and fallen leaves, or by mycelium resident in infected branches. In addition to the ascidian spores formed on the alternate host. This disease is suitable for warm, humid weather...
- The period from infection to the appearance of symptoms is 7-10 days under appropriate conditions.
- Losses of disease spread
- Severe premature leaf fall, leading to a decrease in the quality of the crop and fruit.
- Poor growth of shoots the following year and thus lower yield
- Control strategy
- Preventive measures to prevent the occurrence of the disease
- Remove all diseased wood and burn it.
- Planting resistant varieties
- Proper pruning
- In valleys, it helps diseases develop, so avoid planting in valleys if possible
- Plant trees in a design that allows maximum airflow through the orchard allowing rapid drying of foliage
- Chemical and organic control recommendations
- Organic control: extermination of anemones. In dry areas, the infestation is minimal, so trees must be monitored if the pest appears and we can fight it. In wet areas, treatment must be preventive and regular
- Chemical control: Wettable sulfur, tebuconazole, or azoxystrobin, applied after discovering stem lesion (ASLD) and before expected rain.
- strobilurin fungicides (eg azoxystrobin)
- Bordeaux mixture or 1-20 lime sulfur is applied in late bud swelling.
- References
- SOTO-ESTRADA, A., et al. New fungicides and application strategies based on inoculum and precipitation for managing stone fruit rust on peach in California. Plant Disease, 2003, 87.9: 1094-1101
- Hutton, K. E. (1950). Rust of stone fruit trees. Agricultural Gazette of New South Wales, 61(3).
- RAM, Ved; BHARDWAJ, LN Stone fruit diseases and their management. In: Diseases of Fruits and Vegetables: Volume II: Diagnosis and Management. Dordrecht: Springer Netherlands, 2004. P. 485-510
- Bhat, M.A., Khan, N.A., & Qazi, A. (2014). First record of rust caused by Tranzschelia discolor (Fuckel) Tranz. &Litv. On stone fruits in Jammu & Kashmir (India). Applied Biological Research, 16(2), 264-265
- Herbiguide (Viewed Nov 2019), 'Rust of Stone Fruit',
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