Presented to Ehe Universily of Manitoba in Partial Fulfillment of the Requirements of the Degree Of
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INSECT PEST PROBLEI'ÍS OF SIJNFLOI'IER wITItPARTICI]LARREFERENCET0IIIESI]NFLOI^IER MANTTOBA BEETLE, ZYGOGRAMI'fA EXSLAI'IATIONTS (FABRfCTUS), rN by Yakub Daud Deedat A THESIS presented to Ehe Universily of Manitoba in Partial fulfillment of the requirements of the degree of MCTOR OT' PHILOSOPHY IN TIiE DEPARTMENT OF ENTOMOLOGY Winnipeg, ìfanitoba, 1987 (c) Yakub Daud Deedat Permission tras been granted L'autorisation a êtê accordêe to the National LlbrarY of à la BÍbliothèque nationale Canada to nicrofilm this du Canada de microfilner thesis and to lend or sell cette thèse et de Prêter ou copies of the film. de vendre des exemPlaires du film. The author (coPYright owner) Lrauteur (titulaire du droit has reserved other d'auteur ) se rêserve les publication rights, and autres droits de Publication; áe lther the thes is nor nl la thèse ni de longs extensive extracts from it extraits de celle-ci ne may be printed or otherwise doi vent être inPr i¡nêe ou reiroduðea witTrout his/her autrement reProduits sans aon written pernission. autorisatlon écrite r sBN 0-31-5-4 4L84-4 INSECT PESÎ PROBI.E}IS OF SIINFIOIIER IÍII.E PARTICTII.AR RET-BBSNCE T() TEE STII{FIOIiIER tdAt{I'fOBA BEETLE, zycocRAHuAZYGOGRÂÌíüA EXCI¡AHATIONIq (raBRICiltS), Itr BY YAKTIB DAI'D DEEIIAT A thesis sub¡¡rittcd to thc l--actrlty of cracltrate studies of the U¡riversity of Manitoba in partiat futfillnrent of tlte reqttirerttettts of the degree of DOCTOIì OF PHI LOSOPI-IY @ 1987 permissio¡r has bee¡r granted to tl¡e LIBRARY OF THE UNIVER- slTY OF MANTTOBA to tend or setl copies of this thesis, to tIrE NATIONAL LIBRARY OF CANADA tO MiCTOfiINT tITiS thesis a¡rd to tend or sell copies of the film, and UNIVERSITY MICROFILMS to pubtish an abstract of this thesis' the The author reserves ottrer pubticatio¡r rights, and neither thesis nor extensive extracts from it may be printed or other- wise reproduced without the author's written permission. This thesis is dedicated to my beloved mother, Khatija Daud Deedat, and my late father, Daud Hussien Deedat. lulay it also serve as a source of inspiration to my nephews, Daud, Mohmed and Z:ubair; and my nieces, Zaíntb, Summayya, Amina and Khatija. I]- Deedat , Yakub Daud, Ph. D. The University of Manitoba; 1987 Insect Pest Problems of Sunflower with Particular Reference to Èhe Sunflower Beetle, Zygogramma exclamationis ( Fabr icius ) , in Manitoba. Major Professor: Dr. P.A. MacKav ABSTRACT Data for this study rrere collected during the summers of i9B3 to 1985. Field and grower surveys were conducted to determine the status of the sunflower-insect pest complex as well as their management by growers. Sunflower beetle, sunflower midge, sunflorver maggot, banded sunflower moth and sunflower moth were the most prevalent species and found in at least 10 of the I2 fields that were surveyed. However, pests of primary concern to growers \¡Iere the sunflower beetle, the sunflower midge and cutworms. Cultural control did not play a major role in the management of these pests. lulore than 80% of the growers indicated that they use from the economic thresholds when available. However ' data field survey on sunflower beetle showed that growers applied insecticides at we1.1 below the currently recommended threshold values. Insect densities \^¡ere manipulated on individual Plants in caged and open studies to determine the effect of defoliation of sunflower bv sunflower beetle. Head ]-rr diameter, yield and seed weight decreased' whereas oi1 content increased with increasing beetle densities. A curvilinear relationship between pest density and yield was obtained for adults and larvae. These quadratic polynomial regressions were used to estimate Lhe economic thresholds which ranged from 2-3 adults and 5-10 larvae per plant. sunflower plants were artificially defoliated at five growth stages using four levels of defolíation Ëo simulate time of damage and time of insecticide application in relation to the sunflower beetle. Growth and yield componenrs generally decreased with increasing levels of defol iarion . Plants in their early growth stages ( v4-vB) were most sensitive to defoliation. Plants showed compensation at 1ow 1evels of defoliatíon. Depending on the duration of defol iation , a linear or a quadratic relationship between yield and defoliation was obtained. These relationships were used to calculate defoliation thresholds for indÍvidual growth stages. A sequential decision plan for the control of sunflower beetle larvae was developed from studies of larvaI dispersion in growers t fields. Iwao t s patchiness regression technique was used as a basis for the sequential model since it provided a consistently good fit to the data' The plan should mÍnimize sampling efforts and provide a reliable method of assessing whether control is required' iv ACKNOWLEDGEMEN TS The author expresses his sincere appreciation to Dr. guidance P. A. l'{acKay , Depar tment of Entomology, f or ' counsel, and encouragement given throught this study. I also thank Drs. L.D. Charlet, S.C. J.y, S.R. Rimmer and R'E' Roughley for helpful suggestions and for reviewing the manuscri pts. Thanks are due to Drs. N.J. Holliday and R.J. Lamb for assistance with statistical analysis, and Miss M.T. Sheridan for aid with computor programming. Appreciation is also given to A. Canvin, D. Po11ock, A. Szumigalski and D - \nlright for theír technical assistance as well as to the growers on whose farms the experirnents were conducted. Thanks are also extended to C. S. P. Foods, Altona, Manitoba Pool Elevators , l,,linnipeg, and Cargi1l, E1m Creek, f or their assistance and cooperation in the surveys. I am deeply appreciative of the hospitality, assistance, cooperation and interest taken in my work by friends and fe11ow graduate students of the Department of EntomologY. The Special Research Fellowship and the study leave granted by the University of Zambia as well as the financial assistance provided by Canadian International Development Agency, are sincerely appreciated. To my numerous friends Ín Zambia, and in particular, Ayyub Musa, Yousuf lulusa and Abdul Munshi, whose regular contact bridged the gap between Canada and Zambía, my gratitude is acknowledged. To my mother, my sister Memuna, and two brothers, supPort concern Yousu f and Ismail: your understanding ' ' confidence and love have been the strongest influences for the completion of this dissertation and of my graduate study program. I express my respect and indebtedness to you all. V1 TABLE OF CONTENTS Paoa ABSTRACT iÍ iu ACKN Ol^l LEDG EMEN TS L]ST OF TABLES viii LIST OF FIGURES x LIST OF APPENDICES xiíi Chapter 1. INTRODUCTION I i. t. Problems I I.2. 0bjectives 1.3. Thesis organization 1 2. LITERATURE REVIEI,J I 2.I. The Sunflower Plant B 2.I.1. Domestication and development 8 2.I.2. Culture and Production 10 2.1.3. Uses and f uture 13 2.2. The Sunflower BeetIe i6 2.2.I. Geographic distribution and status 16 2.2.2. Life historY and bÍo1ogY I7 2.2.3. Damage and control 1B 2.3. Economic Thresholds 22 ' 2.3.I. Definitions 22 2.3.2. Determination and use 24 2.4. Sequential Sampling 27 2.4 .1. Development 27 2.4.2. Application 31 3. EXPERIMENTAL STUDIES 34 SECTI0N I: Insect Pests of Sunf 1ot+er and their l"fanagement by Growers in Manitoba. 35 Introduction 37 Materials and Methods 3B Results 4T Discussion f4 vtl SECTION II: Damage Assessment and Economic Thresholds of the Sunflower Beetle, Zyeoqramrna exclamationis (Coleoptera : ffi;lGomãFdaeT; on F-fTower i n lulanitoba . 1'7 Introduction 79 Materials and llethods 80 Results and Discussion B4 SECTI0N III: Impact of Artificial Defoliation on Yield of Sunflower. to2 Introduction 104 Ivlaterials and Methods 105 Results 108 Discussion 115 SECTI0N IV: Spatial Dispersion and Sequential Sampling Plan for Larvae of Sunflower Beetle, Zygggramma exclamationis (Coleoptera: Chrysomelidae ) . r29 Introduction 131 Materials and Methods 132 Results and Discussion 135 4. GENERAL DTSCUSS]ON r49 q CONCLUSIONS l5B 6. R E FER EN CES 10u VII]- LIST OF TABLES CHAPTER 3, SECTION I: Table: F-Tccurrence of sunflower insect pests in twelve farms in Man i toba , 1 983 . 61 2. Duration, mean densities, and mean percent infestation of four sunflower insect pests in twelve farms in ManiLoba, 1983. 62 3. Dates and density aL which insecticides were applied to control sunflower beetle larvae in eleven farms in Manitoba, 1983. OJ 4. Sunflower insect pests, in order of importance to grower s in Man itoba , 1 983- f9B4 . 64 5. Adjustment of planting time, for the management of sunflower insect pests' by growers in Manitoba, 1983-1984. Áq 6. Awareness, use, and effectiveness of economic thresholds to sunflower growers in Manitoba, r983-1984. 66 CHAPTER 3, SECTION II: TabIe: Tl--Regression coefficients for the relationship between plant components (V) and sunflower beetle density (*) in Manitoba, 1984-f985. 96 2. Effect of four densities of sunflower beetle on sunflower yield in Manítoba , 1984-1985. 97 3. Rate of decline of sunflower beetle larvae in three studies at Glenlea, Manitoba , 1984. 98 4. Rate of decline of sunflower beetle larvae in three studíes at Glenlea, 14anitoba, 1985. 99 5. Plethod of insecticide spraying and economic thresholds for the sunflower beetle in IvlaniÈoba, 1984-1985. 100 ]-X CHAPTER 3, SECTION III: Table: 1. Regression coefficients relating percent defol iation ( * ) to groL¡th and yield components of sunflower ( y), for five growth stages, simulating time of damage. I22 2. Effect of four levels of defoliation aL five growLh stages, simulating time of damage, on yield of sunflower. 723 3. Regression eoefficients relating percent defoliation (x) to groh,th and yield components of sunflower (y), for five growth stages, simulating t.ime of insecticide application. I24 4.