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Production of conidia by Peronosclerospora sorghi on sorghum crops in Zimbabwe
Author(s) -
Bock C. H.,
Jeger M. J.,
Mughogho L. K.,
Mtisi E.,
Cardwell K. F.
Publication year - 1998
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1046/j.1365-3059.1998.00235.x
Subject(s) - conidium , sorghum , downy mildew , biology , agronomy , horticulture , botany
Factors affecting the production of conidia of Peronosclerospora sorghi , causing sorghum downy mildew (SDM), were investigated during 1993 and 1994 in Zimbabwe. In the field conidia were detected on nights when the minimum temperature was in the range 10–19°C. On 73% of nights when conidia were detected rain had fallen within the previous 72 h and on 64% of nights wind speed was < 2.0 m s −1 . The time period over which conidia were detected was 2–9 h. Using incubated leaf material, conidia were produced in the temperature range 10–26°C. Local lesions and systemically infected leaf material produced 2.4–5.7 × 10 3 conidia per cm 2 . Under controlled conditions conidia were released from conidiophores for 2.5 h after maturation and were shown to be well adapted to wind dispersal, having a settling velocity of 1.5 × 10 −4 m s −1 . Conditions that are suitable for conidia production occur in Zimbabwe and other semi‐arid regions of southern Africa during the cropping season.