impact of common pesticides on beneficial arthropods in the almond orchard

85 Pages·2015·1.61 MB·English

by  Nathan Cannell

ABSTRACT
IMPACT OF COMMON PESTICIDES ON BENEFICIAL
ARTHROPODS IN THE ALMOND ORCHARD
Field and laboratory studies were conducted to assess the impact of
pesticides on pest mites and beneficial arthropods in an almond orchard. In the
field, the pesticides Brigade, Agrimek, Envidor, Onager and Zeal were applied in a
replicated design and weekly leaf samples were collected to assess pesticide
impact on the population dynamics of the insects. In the laboratory, the
aforementioned pesticides were tested against the beneficial arthropods Goniozus
legneri, Copidosompsis plethorica, Chrysoperla rufilabris, Scolothrips
sexmaculatus, and Aphytis melinus via direct and indirect bioassays to evaluate
lethal and sublethal effects. Field results were inconclusive, primarily due to a low
mite population, thereby reducing beneficial arthropod presence. In laboratory
bioassays, Brigade caused significantly higher mortality values against all
arthropods tested except C. rufilabris. Agrimek caused significantly higher
mortality rates in C. plethorica, A. melinus, and S. sexmaculatus, as well as
reduced parasitism rates by G. legneri. Envidor had little impact on C. plethorica
and S. sexmaculatus; similarly, Onager had little impact on A. melinus and C.
plethorica, and Zeal had little impact on S. sexmaculatus.
Nathan Curt Cannell
December 2015

IMPACT OF COMMON PESTICIDES ON BENEFICIAL
ARTHROPODS IN THE ALMOND ORCHARD

by
Nathan Curt Cannell

A thesis
submitted in partial
fulfillment of the requirements for the degree of
Master of Science in Plant Science
in the Jordan College of Agricultural Sciences and Technology
California State University, Fresno
December 2015
APPROVED
For the Department of Plant Science:

We, the undersigned, certify that the thesis of the following student
meets the required standards of scholarship, format, and style of the
university and the student's graduate degree program for the
awarding of the master's degree.

Nathan Curt Cannell
Thesis Author

Anil Shrestha (Chair) Plant Science

Andrew Lawson College of Science and Mathematics

Kent Daane Environmental Science, Policy and Management, UCB

For the University Graduate Committee:

Dean, Division of Graduate Studies
AUTHORIZATION FOR REPRODUCTION
OF MASTER’S THESIS

X I grant permission for the reproduction of this thesis in part or in
its entirety without further authorization from me, on the
condition that the person or agency requesting reproduction
absorbs the cost and provides proper acknowledgment of
authorship.

Permission to reproduce this thesis in part or in its entirety must
be obtained from me.

Signature of thesis author:
ACKNOWLEDGMENTS
I want to thank all of the people who contributed in one way or another in
the completion of this thesis. This would not have been possible without the
guidance, patience and wisdom of my thesis committee. Dr. Lawson, thank you so
much for always being there and answering every inquiry, be it large or small, as
well as assisting me throughout the graduate school process. Dr. Daane, thank you
for sharing your vast knowledge and contributing guidance throughout the years.
Dr. Shrestha, thank you for all your contributions in handling the data and editing
of the thesis. Additionally, I would like to thank Nichols farms and Lewis Wright
for giving me the resources to conduct my field trials, Gary Weinberger for help
with the field trials, Glenn Yokota and all the staff from the Daane Lab at the UC
KARE research station for helping me immensely with the lab portion of my
thesis, and the entire faculty associated with the Fresno State Plant Science
department. Finally, I’d like to thank my family who has been and always will be
there for me, Bowser for always being there and Amanda for helping me see the
light at the end of the tunnel. Isaac Newton said it best when he said "If I have
seen further than others, it is because I stand on the shoulders of giants".
TABLE OF CONTENTS
Page
LIST OF TABLES .................................................................................................. vi
LIST OF FIGURES ................................................................................................ vii
INTRODUCTION .................................................................................................... 1
LITERATURE REVIEW ......................................................................................... 4
Pests and their Natural Enemies ........................................................................ 4
Important Pest and Beneficial Arthropods in the Almond System ................... 6
Popular Pesticides Used in Almond Production ............................................. 12
POPULATION DYNAMICS OF PHYTOPHAGUS MITES AND
BENEFICIAL ARTHROPODS FOLLOWING PESTICIDE
APPLICATION IN A FIELD SETTING .................................................... 16
Abstract ........................................................................................................... 16
Introduction ..................................................................................................... 16
Materials and Methods .................................................................................... 19
Results ............................................................................................................. 23
Discussion ....................................................................................................... 27
LETHAL AND SUBLETHAL EFFECTS OF SEVERAL PESTICIDES ON
ALMOND BENEFICIAL ARTHROPODS ............................................... 30
Abstract ........................................................................................................... 30
Introduction ..................................................................................................... 30
Materials and Methods .................................................................................... 35
Results ............................................................................................................. 43
Discussion ....................................................................................................... 60
REFERENCES ....................................................................................................... 65
LIST OF TABLES
Page
Table 1. Chemicals tested for impacts upon arthropod population dynamics in
the almond systems .................................................................................. 21
Table 2: Chemicals used to test for lethal and sublethal effects in the
laboratory ................................................................................................. 37
LIST OF FIGURES
Page
Figure 1: Number of pest mites per leaf; values are mean mites per leaf pooled
across all treatments (Nichols plot, Hanford, CA).................................. 24
Figure 2: Number of beneficial arthropods per leaf (Nichols plot, Hanford,
CA) .......................................................................................................... 25
Figure 3: Ratio of beneficial arthropods to phytophagous mites per leaf
(Nichols plot, Hanford, CA) ................................................................... 25
Figure 4: Number of pest mites per 840 leaves sampled (Lewis plot, Reedley,
CA) .......................................................................................................... 26
Figure 5: Number of beneficial arthropods per 840 leaves sampled (Lewis
plot, Reedley, CA) .................................................................................. 27
Figure 6: Percentage mortality of directly treated C. rufilabris ............................. 44
Figure 7: Mean prey consumed by directly treated C. rufliabris ........................... 45
Figure 8: Percentage of adult emergence of directly treated C. rufilabris ............. 46
Figure 9: Percentage mortality of indirectly treated C. rufilabris .......................... 47
Figure 10: Mean prey consumed of indirectly treated C. rufilabris....................... 48
Figure 11: Adult emergence of directly treated C. rufilabris ................................. 48
Figure 12: Percentage mortality of directly treated G. legneri .............................. 49
Figure 13: Percentage parasitism of directly treated G. legneri ............................. 50
Figure 14: Mean offspring of directly treated G. legneri ....................................... 50
Figure 15: Progeny sex ratio of directly treated G. legneri .................................... 51
Figure 16: Percentage mortality of indirectly treated G. legneri ........................... 52
Figure 17: Percentage parasitism of indirectly treated G. legneri .......................... 53
Figure 18: Mean offspring of indirectly treated G. legneri .................................... 53
Figure 19: Progeny sex ratio of indirectly treated G. legneri ................................. 54
Figure 20: Percentage mortality of directly treated C. plethorica .......................... 55
Figure 21: Percentage mortality of indirectly treated C. plethorica ...................... 56
viii viii
Page
Figure 22: Percentage mortality of directly treated A. melinus .............................. 57
Figure 23: Percentage mortality of Indirectly Treated A. melinus ......................... 58
Figure 24: Percentage mortality of directly treated S. sexmaculatus ..................... 59
Figure 25: Mean eggs cosumed by directly treated S. sexmaculatus ..................... 59
Figure 26: Percentage mortality of indirectly treated S. sexmaculatus .................. 61
Figure 27: Mean eggs consumed by indirectly treated S. sexmaculatus ................ 61