EARLY DETECTION, MONITORING AND CONTROL OF GREENHOUSE WHITEFLIES ON CUCUMBER USING YELLOW STICKY TRAPS AND ENCARSIA FORMOSA DQNALD QU I R I NG B.Sc., U.B.C., 1981 PROFESSIONAL PAPER SUBMITTED IN PARTIAL FULFILLMENT 3F THE REQUIREMENTS FOR THE DEGREE OF MASTER OF PEST MANAGEMENT in the Department of BIOLOGICAL SCIENCES @ DONALD QUIRING 1986 SIMON FRASER UNIVERSITY August 1986 All rights reserved, This work may not be reproduced in whole or in part, by photocopy or other means, without permission of the author. Approval Name : Dona1d J .M. Quiri ng Degree: Master of Pest Management Title of Professional Paper: Early detection, monitoring and control of greenhouse whiteflies on cucumber using yellow sticky traps and Encarsia formosa. f Exami ning Committee: Chai rman: Dr. B. Roitberg -- Prof. T. Finlayson, ProfesZ'or-Emerita, Senior Su pe rvisor \ Dr. Jl Borden, Professor ~r.a. Gil lespi e, ~esea7ch~ci inti f t, Research & Plant Quarantine Station I Dr. R.A. Costel lo, O.C. Ministry of Agriculture and Food, External Exami ner August 14, 1986 Date approved ii PARTIAL COPYR l GHT LICENSE I hereby grant to Simon Fraser Unlverslty the right to lend my thesis, proJect or extended essay (the fltle of whlch is shown below) to users of the Simn Fraser Unlversl ty LI br;ry, and to make partial or . single copies only for such users or In response to a request from the I ibrary of any other unlversity, or other educatlona I Instltut Ion, on its own behalf or for one of Its users. I further agree that permission for multiple copylng of thls work for scholarly purposes may be granted by me or the Dean of Graduate Studies. It Is understood that copying or publication of thls work for flnanclal gafn shall not be allowed without my written permisston. T lt l e of Thes ls/ProJect/Extended Essay Early detection, monitoring and control of greenhouse whiteflies on cucumber - using yellow sticky traps and Encarsia formosa. Donald J.M. Quiring (name &t.q, 14/r6 0 (date) . ABSTRACT A review of the literature on the greenhouse whitefly, Tri a1 eurodes vaporari orum (Westwood) and its parasite, Encarsi a formosa (Gahan), revealed that a major reason for the failure of E. formosa to control whitefly populations in greenhouses on cucumber is that introductions are made when whitefly numbers are too high to be controlled below tolerable levels. A yellow trap coated with Stiky Stuff@, was developed for early detection, monitoring and control of whitefly adults. f Although a bright yellow paint was the most attractive color to T. vaporariorum of those tested under laboratory conditions, no color was significantly more attractive than the others under greenhouse conditions. Traps hung at the level of the top of the canopy caught significantly more whiteflies than those hung 30 cm above or below that level.. In trials conducted in a small greenhouse, traps placed at a density of 1 per plant caught 62 per cent of whitefly adults introduced. Traps introduced at this density into a heavily-infested crop reduced whitefly numbers in the greenhouse by 71 per cent in 28 days. Trials in a large commercial greenhouse showed that whitefly adults could be detected on traps hung at densities of 1 per 2 plants, 1 per 5 plants and 1 per 10 plants before they could be found on the plants. Traps at a density of 1 per 2 plants also provided accurate estimates of the numbers of whiteflies on the tops of the plants. A regression equation was calculated between the numbers of whiteflies on the traps and the numbers of whiteflies on 9 upper leaves below each trap each week. Traps at a density of 1 per 2 plants in conjunction with E. formosa were most effective at controlling whiteflies at low levels when traps were introduced before whiteflies had become established on the crop. When introductions were made into progressively larger whitefly infestations, whitefly numbers increased at progressively faster rates. Small infestations could be reduced by a complete inundation of traps into the area. However, a large whitefly pspulation in the greenhouse could not be controlled by traps placed at a density of 1 per 2 plants. Management practices also affected whitefly control. The removal from the greenhouse of leaves and shoots bearing parasitized whitefly scales in spring and an insecticide application for thrips in summer severely reduced E. formosa numbers. An examination of leaves and shoots 5or presence of parasites prior to removal from the greenhouse are recommended to reduce such losses. Preventative measures such as removal of non-crop plants from inside and immediately around the greenhouse can be taken to reduce the risk of whitefly infestations early in the season. ACKNOWLEDGEMENTS I thank the following people for their assistance during this study: Mr. Ludwig DeJong for the use of his greenhouse; the B.C. Greenhouse Growers' Research Committee for funding this study; Mr. Brian Mauza for introducing me to the growers and for his interest in the project; Mr. Don Elliott for his advice and for supplying the biological control agents; my parents, Mr. and Mrs. John Quiring, who helped to construct cages and the small greenhouse; Dr. J.H. Borden for his review of the manuscript; and Dr. D.R. Gillespie for valuable discussions throughout this study. I particularly wish to thank my senior supervisor, Prof. T. Finlayson for her encouragement and support throughout this study. TABLE OF CONTENTS Approval .................................................... ii ABSTRACT ................................................... iii ACKNOWLEDGEMENTS ............................................ v List of Tables .............................................. ix List of Figures ........................................... x INTRODUCTION .....................,.....*.*.**t... m.1 A . LITERATURE REVIEW .....................*..................4 1 . TRIALEURODES VAPORARIORUM .......................... 5 Systematics. Origin and Distribution ............... 5 Biology and Description of Life Stages ............. 6 Ecology ........................................... 11 Distribution .................................... 11 Host Selection .................................. 11 Cmtrols .......................................... i3 History of Chemical Control ..................... 13 History of Biological Control ................... 15 Integrated Control .............................. 16 PI . EKARSIA FORMOSA .................................. 17 Systematics. Origin and Distribution .............. 17 Biology and Life History .......................... 17 Ecology ........................................... 20 Introduction Methods .............................. 22 Pest-in-First Method ............................ 22 Banker Plants ................................... 23 Multiple Release Methods ........................ 24 I11 . FACTORS AFFECTING THE PARASITE-HOST INTERACTION ... 27 Timing ............................................ 27 Number. Frequency and Rate of Parasite Introductions ................................... 28 Environmental Conditions .......................... 30 Temperature ..................................... 30 Light .......................................... 31 ~umidity ........................................ 32 Plant Type ........................................ 32 Insecticides ...................................... 33 OTHER CONTROLS ................................... 34 Plant Resistance .................................. 34 Other Parasites ................................... 34 Insect Parasites ................................ 34 Fungal Pathogens ................................ 35 Predators .......................................... 36 Traps ............................................. 36 B . EFFICACY OF YELLOW STICKY TRAPS FOR MONITORING AND CONTROL OF THE GREENHOUSE WHITEFLY ...................... 38 V . INTRODUCTION ...................................... 39 VI . TRAP DEVELOPMENT .................................. 40 Materials and Methods ............................. 40 Effect of color on trap catch ................... 43 Effect of shape on trap catch ................... 44 Effect of sticky substance on trap catch ........ 44 Effect of height on trap catch .................. 46 Results and Discussion ............................ 46 vii Effect of color on trap catch ................... 46 Effect of shape on trap catch ................... 53 Effect of sticky substance on trap catch ........ 53 Effect of trap height on whitefly catch ......... 57 VII . PRELIMINARY GREENHOUSE TRIALS ..................... 58 Materials and Methods ............................. 58 Prevention of whitefly establishment by traps ... 61 Efficacy of traps for control ................... 61 Results and isc cuss ion ............................ 61 Prevefition of whitefly establishment by traps ... 61 Efficacy of traps for control ................... 62 VIII . COMMERCIAL GREENHOUSE TRIALS ...................... 64 Materials and Methods ............................. 64 Efficacy of traps for early detection ........... 66 Efficacy of traps for monitoring ................ 66 Efficacy of traps for controi ................... 66 Results and Discussion ............................ 67 Grower ~eaction ................................. 67 Whitefly Population Trends ...................... 68 Efficacy of traps for early detection ............ 69 Efficacy of traps for monitoring ................ 71 Efficacy of traps for control ................... 73 Grower Practices ................................ 77 CONCLUSIONS ..............................................