|Title||Epidemiology and biological control of grey mould in annual strawberry crops|
|Source||Wageningen University. Promotor(en): A.H.C. Van Bruggen; J. Koehl. - S.l. : S.n. - ISBN 9789058083654 - 128|
Biological Farming Systems
|Publication type||Dissertation, internally prepared|
|Keyword(s)||aardbeien - fragaria - botrytis cinerea - teeltsystemen - schimmel - biologische bestrijding - epidemiologie - vruchtrot - bloei - bloemen - bloemkroon - plantenziekten - strawberries - fragaria - botrytis cinerea - plant diseases - cropping systems - moulds - biological control - epidemiology - fruit rots - flowering - flowers - corolla|
|Categories||Epidemiology of Plant Pests and Diseases / Biological Control of Diseases / Small Fruits|
Intensive crop production has led to various undesirable side effects. Strawberry production is typically very input-intensive, in particular with respect to fungicides. In this thesis we attempt to develop a control strategy for strawberry grey mould caused by Botrytis cinerea Pers. using an ecological approach. The epidemiology and biological control of grey mould using the antagonist Ulocladium atrum Preuss was studied during four years in an annual cropping system under field conditions. U. atrum sprayed throughout the season controlled grey mould on fruits effectively in five of eight experiments. On the phylloplane, U. atrum spore density declined exponentially with a relative rate of -0.10 day -1. This means that sprays would need to be applied once a week for U. atrum to compete effectively with B. cinerea in dead leaf tissue. However, very little leaf debris was formed in annual strawberry and the pathogen sporulated on a maximum of 15.5 cm² of leaf area per plant. Crop sanitation by removing dead leaves did not affect the level of grey mould. These results demonstrate that crop debris was not a significant inoculum source for B. cinerea in this strawberry system. The presence of petals can facilitate the establishment of infection of B. cinerea on fruits, considering that 65-85% of them exhibited pathogen sporulation, and petal retention during fruit development was associated with 50% of the total grey mould. Therefore targeting the infection of B. cinerea on flower parts is more efficient for the control of grey mould than suppressing sporulation of the pathogen on crop debris. Spraying U. atrum during flowering was as effective as spraying from transplanting. A single application of U. atrum was effective in reducing grey mould when introduced at late flower- or early fruit stages. Multiple applications during flowering showed that twice weekly sprays gave better control than weekly sprays. The conidium concentration of U. atrum can be as low as 0.5 x 10 6conidia ml -1when applied at flowering.