Root-boring insects in Gutierrezia sarothrae Item Type text; Thesis-Reproduction (electronic) Authors Falkenhagen, Thomas Jay, 1952- Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 06/10/2021 09:28:59 Link to Item http://hdl.handle.net/10150/348286 ROOT-BORING INSECTS IN GUTIERREZIA SAROTHRAE' by Thomas Jay Falkenhagen A Thesis Submitted to the Faculty of the SCHOOL OF RENEWABLE NATURAL RESOURCES In Partial Fulfillment of the Requirements For the Degree of MASTER OF SCIENCE WITH A MAJOR IN WATERSHED MANAGEMENT In the Graduate College THE UNIVERSITY OF ARIZONA 1 9 7 8 STATEMENT BY AUTHOR This thesis has been submitted in partial fulfillment of re­ quirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library, Brief quotations from this thesis are allowable without special permission, provided that accurate acknowledgment of source is made, Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his judg­ ment the proposed use of the material is in the interests of scholar­ ship. In all other instances, however, permission must be obtained from the author. SIGNED: APPROVAL BY THESIS DIRECTOR This thesis has been approved on the date shown below: ( * ' ■ I i A \ AAX ^ / /\prd IZ , |. 0. KLEMMEDSON Date Professor of Range Management ACKNOWLEDGMENTS I would like to express my sincere appreciation to Dr. Robert Eye of the Agricultural Research Service for his support and guidance during this project, Dr. James Klemmedson for his assistance in orga­ nizing and preparing my graduate program and thesis, Dr. Malcolm Zwolinski and Dr. William Nutting for their review of this manuscript, and Dr. Floyd Werner for his assistance in identification of the in­ sects. I would also like to thank my wife, Kathy Peters, for her patience and assistance during my graduate work and the preparation of this thesis. iii TABLE OF CONTENTS Page LIST OF ILLUSTRATIONS . ........................................ v LIST OF TABLES QoooaOQOo oooooooo«o oo« VXil ABSTRACT @ <? <? & o » o & » » » <> <? <? © © » © © © © © © v n i 1© INTRODUG T10N © © © © © © © © © ©. © © © % © © © © © © © © * 1 2 a LITERATURE REVIEW © © © © © © © © © © © © © © © © © © © © © 3 3 & METHODS © © © © © © © © © © © © © © © © © © © © © © © © © © 10 Field Sampling Area © © © © © © © © © © © © © © © © © © 10 Plot Layout and Sampling Method © © © © © © © © © © © © 10 Inspection of Plants and Larvae © © © © © © © © © © © © 12 Rearing Field Gpllections * © © © © © © © © © © © © © 13 Oviposition by Myrm^x lineolata © © © © © © © © © © © © 15 4© RESULTS AND DISCUSSION © © © © © © © © © © » © © © © © © © 19 Identity and Description of Insects © © © © © © © © © © 19 Borers. © © © © © © © © © © © © © © © © © © © © © © 20 Other Root Inhabitants © © © © © © © © © © © © © © 29 Damage and Route of Travel © © © © © © © © © © © © © © 33 Imeplata © © © © © © © © © © © © © © © © © 33. Hi. Pponielas^ carol mens, is © © © © © © © © © © © © © © 37 ° ° ° 0 0 © © © © © © © © © © © 39 Borer Associations and Combined Effects © © © © © © 41 Field Density © © © © © © © © © © © © © © © © © © © © © 42 Borer/PIant Relationships © © © © © © © © © © © © © 42 Borer/Plant Height Relationships ©©©©©©©©© 47 Role of Borers as Weed Control Agents ©©»©,©©»» 52 LIST OF REFERENCES © © © © © © © ©.© © © © © © © © © © © © 58 IV LIST OF ILLUSTRATIONS Figure Page 1. Sampling area . 11 2„ Insectary rearing boxes 14 3o Oviposition chamber„» @ » op # » « » « » # » » -» op » # 16 4. Cup and stem arrangement (M=medium, S=stems) ...... 16 5. Myrmex lineolata (Pascoe) (== Qtldocephalus ). A, larva; B, pupa; C, adult ............. 21 6. Number of Myrmex lineolata pupating and emerging during 1976 ................ 23 7. Comparison of emergence by M„ lineolata with mean maximum soil temperatures for the sampling area from February, 1976 through January> 1977. ............. 25 8. Comparison of emergence by M. lineolata with mean moisture percent of G..sarothrae foots from February, 1976 through January, 1977 . ...... # . 26 9. Hippomelas carolinensls (Horn). A, larva; B, adult .-. ... O . 9 . O O . 9 9 9 . # . " 9 28 10. Chrysobothris arizonica (Chamberlain). Adult ...... 30 11. Agrilus glbbicollis (Fall). A, larva; B, adult ..... 30 12. Enoclerus laetus nexus (Barr). A, larva; B, adult . 32 13. Mordella species. A, larva; B, adult .......... 34 14. Route of travel and damage by Myrmex lineolata in Gutierrezia roots. A, longitudinal root section; B, cross“Sections ............. 35 v vi LIST OF ILLUSTRATIONS— Continued Figure Page 15. Route of travel and damage by Hippomelas carolinensis in Gutierrezia roots. A, longitudinal root section; B, cross- sections o O » O _ -O O e ff O G O o o o O ' o o o g o o o o 38 16. Route of travel and damage by Agrilus gibbicollis in Gutierrezia roots, A, longitudinal root section; B, cross- sections ...a,..,...,....,.,..,. 40 17. Percentage of plants infested with Myrmex lineolata over the sampling period .......... 43 LIST OF TABLES Table Page 1. Number and percentage of G. sarothrae plants infested by any borer 45 2. Number and percentage of G„ sarothrae plants infested by each borer species . , . ............ 45 3„ Mean number of each borer species per plant 46 4, Number and percentage of G« sarothrae plants in each of seven height classes and the number and percentage of these plants currently or formerly infested by borers ............ 48 5, Number and percentage of G„ sarothrae plants in each size class infested by M„ lineolata or H„ c^ai^^l^Ln(^^g^^^ @ @ @ * * * * * * * * 50 6. Mean and maximum numbers of M„ lineolata larvae and mean numbers of H„ carolinensiS larvae per plant in each size class of G, sarothrae . 51 vii ABSTRACT The purpose of this study was to investigate the biology of root-boring insects in Gutierrezia sarothrae, a range weed. This in­ cluded identifying major insects infesting the roots, documenting the approximate damage caused by each type of insect, and determining each insect's approximate life history and field density. Results reflect general trends for a specific area for a limited period of time and should hot be used in other areas without more extensive research. Plants in the field were sampled by a line transect method. Larvae were removed from the roots and reared to adults on artificial lima bean media in the laboratory. Field and laboratory data reflected emergence patterns. Four borer species were reared and identified. These included Myrmex lineolata (Pascoe) (sOtidocephaius) (Curculionidae), Hippomelas carolinensjs (Horn) (Buptestidae), Chrysobothris arizonica (Chamberlain) (Buprestidae), and Agrilus gibbicollis (Fall) (Buprestidae). Possible predators and other root inhabitants included Enoclerus laetus nexus (Barr) (Cleridae), Rhadalus testaceus (Le Conte) (Melyridae), Mordella species (Mordellidae), and Certainiops abdominalis (Brown) (Asilidae). Borers may reduce the ability of G. sarothrae plants to compete with desirable forage plants by damaging supporting tissues in the roots and lowering plant vigor. The potential for using these root-borers for controlling (3. sarothrae plants could not be assessed by the present study; however, further research is warranted. viii CHAPTER 1 INTRODUCTION The purpose of this study Was to investigate the biology of root-boring insects of Gutierrezia sarothrae«, This included identify­ ing major insects infesting the roots, documenting the approximate dam­ age caused by each insect, and determining each insect's approximate life history and field density. Hopefully this information will allow reasonable speculation on the feasibility of using these insects as biological control agents and will suggest further avenues of research to more accurately determine the precise role of foot-borers in damage and mortality of Gutierrezia. Thus, the ultimate objective of this study is to evaluate the capacity of insects to limit populations of G. sarothrae and to determine how these insects might be used to aug­ ment and sustain existing control measures. Preliminary investigations indicated that root-boring insects in Gutierrezia. as with many insect populations, tended to aggregate on certain plants in specific areas. Some plants had high numbers of larvae, while others had few or none. Also, large plants could physically support higher numbers of larvae than could smaller plants. These attributes of insects, the large variations in plant size, and limits of time and facilities, restricted this study to obtaining primarily qualitative information. Of necessity, sampling procedures 1 2 used here bore closer resemblance to a survey than a statistically accurate quantitative sampling scheme. Samples reflected general trends for a specific population, in a small area, for a relatively short period of time. Thus, care should be exercised in extending re­ sults to populations of insects in,Gutierrezia sarothrae in other areas. Such wide application requires extensive research over a wide variety of habitats and is beyond the scope of the present study. CHAPTER 2 LITERATURE REVIEW Gutierrezia