Articles
Occurrence of bitter rot disease in Illinois commercial apple orchards in USA
Article number
1449_32
Pages
241 – 248
Language
English
Abstract
This study was conducted to determine the incidence of bitter rot disease in in Illinois apple orchards and the causal agents of the disease.
Orchard surveys were conducted within three weeks prior to fruit harvest in 2020 and 2021 to assess the incidence of fruit rot.
Five trees of each cultivar were randomly selected and 60 fruits (five fruits in each of the upper, middle, and lower canopies of eastern, northern, western, and southern sides) per tree, were examined for fruit rot symptoms.
Results showed that 20 of 30 orchards and 21 of 33 orchards had symptomatic fruit rot in 2020 and 2021, respectively.
Incidence of the symptomatic fruits ranged from 1 to 100% (mean 27%) in 2020 and from 0.7 to 100% (mean 20%) in 2021. Symptomatic fruits were observed in most of the orchards in central and southern Illinois.
The incidence of fruits with bitter rot symptoms in ‘Empire’, ‘Golden Delicious’, ‘Honeycrisp’, and ‘Jonathan’ apples was higher than the rots in other apple cultivars.
Symptomatic fruits were collected from ‘Braeburn’, ‘Cortland’, ‘Empire’, ‘Fuji’, ‘Gala’, ‘Golden Delicious’, ‘Goldrush’, ‘Granny Smith’, ‘Honeycrisp’, ‘Jonagold’, ‘Jonathan’, ‘McIntosh’, ‘Red Delicious’, apples and one unknown cultivar at 33 different orchards across the state.
Infected tissues were cultured on potato dextrose agar medium, and the pathogens were isolated.
Based on the cultural characteristics and sequences of the glyceraldehydes-3-phosphate dehydrogenase (GAPDH) and
-tubulin 2 (TUB2) genes of 190 isolates, 86, 99, and 5 isolates were identified as Colletotrichum fioriniae, C. siamense, and C. chrysophilum, respectively.
Orchard surveys were conducted within three weeks prior to fruit harvest in 2020 and 2021 to assess the incidence of fruit rot.
Five trees of each cultivar were randomly selected and 60 fruits (five fruits in each of the upper, middle, and lower canopies of eastern, northern, western, and southern sides) per tree, were examined for fruit rot symptoms.
Results showed that 20 of 30 orchards and 21 of 33 orchards had symptomatic fruit rot in 2020 and 2021, respectively.
Incidence of the symptomatic fruits ranged from 1 to 100% (mean 27%) in 2020 and from 0.7 to 100% (mean 20%) in 2021. Symptomatic fruits were observed in most of the orchards in central and southern Illinois.
The incidence of fruits with bitter rot symptoms in ‘Empire’, ‘Golden Delicious’, ‘Honeycrisp’, and ‘Jonathan’ apples was higher than the rots in other apple cultivars.
Symptomatic fruits were collected from ‘Braeburn’, ‘Cortland’, ‘Empire’, ‘Fuji’, ‘Gala’, ‘Golden Delicious’, ‘Goldrush’, ‘Granny Smith’, ‘Honeycrisp’, ‘Jonagold’, ‘Jonathan’, ‘McIntosh’, ‘Red Delicious’, apples and one unknown cultivar at 33 different orchards across the state.
Infected tissues were cultured on potato dextrose agar medium, and the pathogens were isolated.
Based on the cultural characteristics and sequences of the glyceraldehydes-3-phosphate dehydrogenase (GAPDH) and
-tubulin 2 (TUB2) genes of 190 isolates, 86, 99, and 5 isolates were identified as Colletotrichum fioriniae, C. siamense, and C. chrysophilum, respectively.
Publication
Authors
F. Acheampong, A.N. Miller, M. Babadoost
Keywords
summer diseases, fungal diseases, fruit rot, Colletotrichum species, molecular identification
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