POTENTXAL OF PHYSICAL BARRIERS FOR ROOT WEEVIL MANAGEMENT IN NURSERIES Michael K. Bomford B. Sc.(&.), University of British Columbia, 1995 THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF PEST MANAGEMENT in the Department of Biological Sciences Michael Bomford SIMON FRASER UNIVERSITY Apri.19, 1998 AU rights reserved. This work may not be reproduced in whale or in part, by photocopy or other means, without permission of the author. National Library Bibliothèque nationale 1*1 ofCanada du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395, rue Wellington Otiawa ON K1 A ON4 Ottawa ON KIA ON4 Canada Canada The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or sel1 reproduire, prêter, distribuer ou copies of this thesis in rnicrofonn, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/film, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. Abstract Aîthough physical exclusion shows some potential as a novel root weevil control strategy, it has received iittle research attention. Several studies were undertaken in 1997 to assess the potentiai of two physical barriers, alumirium fences and extruded plastic trenches, for root weevil management in local nursery crops. In laboratory tests, fluon and powdered talc both reduced the climbing ability of adult root weevils. In field studies, trenches and fences with Teflon added reduced pooled root weevil immigration into plots of strawbemes by up to 67%. Immigration of the two most commody captured weevils, Nemocestes incomptus (Hom) and Barypeithes pellucidus (Boh.),was reduced by up to 84 and 7396, respectively. Concurrent increases in strawberry plant mass and suxvival were observed. Adding diatomaceous earth to trenches did not increase their efficacy, and fences without Teflon were not effective bamiers. Immigration of carabids < 1 and > 1 cm long, respectively, was reduced by up to 84 and 54% by trenches, and 58 and 99% by fences. Adding diatomaceous earth to trenches or Teflon to fences had no effect on carabid immigration. Field trials with pardel trenches revealed up to 100% weevil escape rates, yet trenches proved a more reliable method of monitoring weevils than pitfall traps, catching larger numbers and a wider variety of curculionid species. Smaii-sale field and laboratoxy trials suggested that surfaces which root weevils cannot climb when dry are made climbable by condensation. Fences weathered field conditions well adare made of comxnerciaUy available components, but their practical potential is limited by their height and considerable labor requirements. Trenches have many disadvantages, includùlg a tendency to trap beneficial insects, shallow soii penetration, and a tendency to crack, bend, and twist under UV exposure and temperature variation. However, most of these problems could be overcome through simple design modifications, their low profile makes them compatible with wheeled farm machinery, and they could potentially kiU root weevils, instead of just excluding them. Both barriers wodd be lesexpensive than chernical controls if used to protect large areas for several years. iii Acknowledgements 1 th&: Jeff Hicks, Pickett's Nurseries and John Traas, Traas Rootstock Nursery, for providing field space and advice; Murray Isman for providing laboratory and field space and computer access; Lynne GLli.net for ofFehg her yard as a weevil collection site, and helping to coiiect specimens; John Borden for advice, assistance, and review of this manuscript; Mark Bomford, Sharon Coliman, Natasha Bassagnova, Richard Cowles, Adony Melathopolous, Linda Gilkeson, Hanna Mathers and Dave Raworth for advice and encouragement. Bob Vernon deserves especidy heartfelt thanks for the enthusiasm, encouragement, knowledge, and support he offered throughout the course of this work. He struck a careful balance between being always available for help, yet offering me enough independence to create my own project and make my own mistakes. His confidence in me gave me confidence in myself. Thanks to my partner, Ga Ching Kong, for listening to me say far more about weevils than she ever wanted to know, and still continuhg to offer support and encouragement. 1 would also like to thank my parents, for supporting me throughout my Me-long education, and continuhg to do so with this project. Their loan of a vehicle when mine broke down proved especially invaluable. This work was supported in paxt by the BC Nursery Trades Association, Agriculture and Agri-Foods Canada, three SFU Graduate Fellowships, the H.R. MacCarthy Graduate Bursary, the Thelma Finlayson Graduate Fellowship, and the BC Councii of Garden Clubs Pxize. Table of Contents APPROVAL ............................................................................................................. i ABSTRACT ............................................................................................................ ii ACKNOWLEDGEMENTS.... ........................... .... ...................................................... iv TABLE OF C0NTENTSaeo.o. ...........b.~*b.~wm.~....w..........~...*..........~~* *.**v LIST OF TABLES .......................... ................... W LIST OF FIGURES .............................m...................................................................ix 1.0 INTRODUCTION ............................................................................................... 1 1.1 Rom WEEWLS .............................................................................................................1 1.1.1 Black vine weeuil .................................................................................................1 1.1.2 Strawberry root weevil, rough strawbeny roof weeuil. and clay colored weevil .... 4 1.1.3 Woods weevil .................................................................................................... 7 1.1.4 Ban/peieithespellucidus ........................................................................................8 1.1.5 Increasing impact ................................................................................................8 L 1.1.6 Control Options .................................................................................................... 9 1.1 . 7 Examples of p hysical crintrols............................................................................ 12 1.1.8 Potential for root weevil management using physid control ..............................14 1.2 OWECTNES.............................................................................................................. 15 2.0 MATERIALS AND MJ3THODS ............................... .......... ............................ 17 2.1 EFFECTOF POWDER AND FLUON ON WEEVIL CLIMBING ABILiTY ...........................................17 2.2 TEST OF PHYSICAL BARRIERS SURROUNDINC) SMALL PLOTS OF RHODODENDRONS AND AZALEAS 18 2.3 PHYSICALBARRIERS SURROUNDINO SMALL PLOTS OF STRAWBERRIES ................................. 2 1 2.4 ESCAPEFROM PARALLEL TRENCHES ...............................................................................23 2.5 BLACKVINE WEEVIL CONTAINMENT IN SMALL ENCLOSURES .......................................... 24 2.6 EFFECTOF CONDENSATION ON BLACK VINE WEEVIL ESCAPES ............................................28 3.0 RESULTS ....................................................................................................... 29 3.1 EFFECT OF POWDER AND FLUON ON WEEVIL CLIMBINO ABILITY ........................................... 29 3.2 PHYSICALBARRIERS SURROUNDING SMALL PLOTS OF RHODODENDRONS AND AZALEAS ..........-29 3.3 TEST OF PHYSICAL BARRIERS SURROUNDING SMALL PLOTS OF STRAWBERRIES .......................34 3.3.1 Weevil catches ...................................................................................................34 3.3.2 Ground beetle catches .......................................................................................39 3.3.3 Plant health ....................................................................................................... 42 3.3.4 Bam'er tueuthering ............................................................................................42 3.4 ESCAPERATE FROM PARALLEL TRENCHES ....................................................................... 45 3.4.1 Pitfall trap catches ............................................................................................. 45 3.4.2 nench catches .................................................................................................49 3.4.3 Trench weathering .............................................................................................49 3.5 BLACKVINE WEEVIL CONTAINMENT WiTHIN SMALL ENCLOSURES ......................................... 54 3.6 EFFECTOF CONDENSATION ON BLACK VINE WEEWL ABILITY TO ESCAPE SMALL CANNISTERS ....-55 4.0 DISCUSSION ................................. ............ .................................................*.*57