Abstract:
In 1981, in the apricot orchards belonging to the Research Station Baneasa-Bucuresti a very serious attack on leaves was caused by Alternaria tenuissima.
This attack could be the result of application of fungicides.
The disease appeared on leaves as of irregular spots of grey-whitish colour which in the end perforates the leaves and cause an early leaf drop.
The fungus develops at temperatures between 18–34°C, generally at a relative humidity above 72.4%. In this case, the incubation time lasts 3 days irrespective of the leaf age.
The behaviour of some apricot hybrids and varieties to this disease was evaluated.
The following varieties and hybrids: Callatis, Saturn, Olimp, Condor, Neptun, Cannette, Cafona, Wenatchee, Early Orange, Mekteb, Skaha, Early Bee, M 22/4, M 55/6, M 37/26, B 33/13 were resistant.
In order to prevent and control the disease, it is suggested to apply several treatments with Thiuram 75 UP (0.3%) when the first disease spots occurred.
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