Effect of cultural methods on leaf spot (Mycosphaerella fragariae) and gray mold (Botrytis cinerea) damage in strawberries

Summary

Damage of leaf spot, caused by Mycosphaerella fragariae and gray mold also called Botrytis fruit rot, caused by Botrytis cinerea, average fruit weight and yield were evaluated with regard to cultural methods over two years. Leaf spot damage decreased significantly by around 90 % due to leaf sanitation (removal of dead and leaf spot infected leaves in early spring) and by 50 % due to plantation in a one-row-system instead of a two-row-system. When all leaves including the healthy green ones were removed in early spring average fruit weight decreased significantly by 10 %. Fruit sanitation - the third treatment – did not influence any of the measured parameters.
Neither leaf sanitation nor fruit sanitation (removal of damaged fruits during harvest) reduced B. cinerea damage significant. Only the combination of a one-row-system, leaf sanitation and fruit sanitation almost halved (not significantly) B. cinerea damage in the first crop year compared to a two-row-system without leaf and fruit sanitation. B. cinerea damage correlated significant positive with the biomass of plants by R2= 0.47. According this study and the cited literature it is suggest for humid Central European conditions to apply a one-row system combined with leaf sanitation in early spring and fruit sanitation during harvest if fruit density is high to reduce the risk of damages in larger dimension caused by M. fragariae and B. cinerea.