An Ecological Study on Red Sorrel (Rumex acetosella L.) in Wild Blueberry Fields in Nova Scotia by Angela D. Hughes Submitted in partial fulfilment of the requirements for the degree of Master of Science at Dalhousie University Halifax, Nova Scotia in co-operation with Nova Scotia Agricultural College Truro, Nova Scotia April 2012 © Copyright by Angela D. Hughes, 2012 DALHOUSIE UNIVERSITY NOVA SCOTIA AGRICULTURAL COLLEGE The undersigned hereby certify that they have read and recommend to the Faculty of Graduate Studies for acceptance a thesis entitled “An Ecological Study on Red Sorrel (Rumex acetosella L.) in Wild Blueberry Fields in Nova Scotia” by Angela D. Hughes in partial fulfilment of the requirements for the degree of Master of Science. Dated: April 18 2012 Supervisor: _________________________________ Readers: _________________________________ _________________________________ _________________________________ ii DALHOUSIE UNIVERSITY AND NOVA SCOTIA AGRICULTURAL COLLEGE DATE: April 18, 2012 AUTHOR: Angela D. Hughes TITLE: An Ecological Study on Red Sorrel (Rumex acetosella L.) in Wild Blueberry Fields in Nova Scotia DEPARTMENT OR SCHOOL: Department of Environmental Sciences DEGREE: MSc CONVOCATION: October YEAR: 2012 Permission is herewith granted to Dalhousie University to circulate and to have copied for non-commercial purposes, at its discretion, the above title upon the request of individuals or institutions. I understand that my thesis will be electronically available to the public. The author reserves other publication rights, and neither the thesis nor extensive extracts from it may be printed or otherwise reproduced without the author’s written permission. The author attests that permission has been obtained for the use of any copyrighted material appearing in the thesis (other than the brief excerpts requiring only proper acknowledgement in scholarly writing), and that all such use is clearly acknowledged. _______________________________ Signature of Author iii Table of Contents List of Tables ..................................................................................................................... vi List of Figures .................................................................................................................. vii Abstract ........................................................................................................................... viii List of Abbreviations and Symbols Used .......................................................................... ix Acknowledgments .............................................................................................................. x Chapter 1 Introduction ....................................................................................................... 1 1.1 Introduction to the Problem .......................................................................................... 1 1.2 Wild Blueberry History ................................................................................................ 3 1.2.1 Species ................................................................................................................... 4 1.2.2 Blueberry Management ......................................................................................... 4 1.3 Weeds in Blueberries ................................................................................................... 5 1.3.1 General Weed Management .................................................................................. 5 1.4. Red Sorrel .................................................................................................................... 7 1.4.1 Species ................................................................................................................... 7 1.4.2 Management .......................................................................................................... 8 1.5 Botrytis Blight .............................................................................................................. 9 1.5.1 Pruning ................................................................................................................ 11 1.5.2 Impact of Weeds on Disease ............................................................................... 12 1.6 Honey bee ................................................................................................................... 13 1.6.1 Species ................................................................................................................. 13 1.6.2 Foraging............................................................................................................... 15 1.6.3 Foraging on Non-Native Weeds .......................................................................... 16 1.6.4 Management ........................................................................................................ 17 Chapter 2 Red Sorrel Management with Pronamide ........................................................ 20 2.1 Introduction ................................................................................................................ 20 2.2 Material & Methods ................................................................................................... 22 2.2.1 Study Sites ........................................................................................................... 22 2.2.2 Experimental Design ........................................................................................... 22 2.3 Statistical Analysis ..................................................................................................... 24 2.4 Results & Discussion ................................................................................................. 24 2.4.1 Impact of Kerb Applications on Blueberries ....................................................... 24 2.5 Conclusions ................................................................................................................ 29 iv Chapter 3 The Impact of Red Sorrel (Rumex acetosella L.) on Honey Bee (Apis mellifera L.) Activity and Botrytis cinerea Spore Germination in a Wild Blueberry Field ................................................................................................................ 30 3.1 Introduction ................................................................................................................ 30 3.2 Materials & Methods .................................................................................................. 33 3.2.1 Study Sites ........................................................................................................... 33 3.2.2 Timing of Blueberry & Red Sorrel Flowering and Sorrel Pollen Release .......... 33 3.2.3 Impact of Red Sorrel Density on Pollinator Activity .......................................... 35 3.2.4 Effect of Red Sorrel Pollen on B. cinerea Spore Germination and Floral Infection........................................................................................................................ 36 3.2.4.2 Effect of Red Sorrel Pollen on Infection of Wild Blueberry Flowers by B. cinerea............................................................................................................. 37 3.3 Statistical Methods ..................................................................................................... 38 3.4 Results and Discussion ............................................................................................... 38 3.4.1 Timing of Blueberry and Red Sorrel Flowering and Sorrel Pollen Release ....... 38 3.4.3 In Vitro Germination of Botrytis cinerea Spores and Red Sorrel Pollen ............ 45 3.4.4 Infection of Mature and Immature Blueberry Flowers by B. cinerea Spores and Red Sorrel Pollen ....................................................................................... 46 3.4.5 Honey Bee Observations ..................................................................................... 48 3.5 Conclusions ................................................................................................................ 56 Chapter 4 Conclusions ..................................................................................................... 58 4.1 Overall Conclusions ................................................................................................... 58 4.2 Recommendations ...................................................................................................... 61 4.3 Management recommendations .................................................................................. 62 References ........................................................................................................................ 64 v List of Tables Table 2.1 Average blueberry stem height and floral bud counts at Mt. Thom and Kemptown Nova Scotia in 2009 and 2010….............. 24 Table 2.2 Density and biomass of red sorrel ramets and blueberry stems at two sites for the 2-year blueberry production cycle in Nova Scotia…………………………………………………………… 26 Table 2.3 Percent ground cover of blueberry and red sorrel in two Nova Scotia fields in 2009 and 2010………………............................. 27 Table 2.4 Blueberry yield and profit after applications of Kerb in the fall and sprout year at two crop year fields in Nova Scotia………… 29 Table 3.1 Crop year blueberry stem density counts in plots with and without red sorrel in a Nova Scotia blueberry field…………….. 54 vi List of Figures