DEVELOPMENT OF PHEROMONE-BASED MONITORING OF ORANGE WHEAT BLOSSOM MIDGE, Sitodiplosis mosellana (GEHIN) (DIPTERA: CECIDOMYIIDAE)

by Lucian Mircioiu B. Sc. (Silviculture), M. Sc. (Forestry) Universitatea "Transilvania" Brasov, ]997

THESIS SUBMITED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF

MASTER OF PEST MANAGEMENT

in the Department of Biological Sciences

© Lucian Mircioiu 2004

SlMON FRASER UNIVERSITY

Fall 2004

All rights reserved. This work may not be reproduced in whole or in part , by photocopy or other means, without permission of the author. IJ

APPROVAL

Name: Lucian Mircioiu

Degree: Master of Pest Management

Title of Thesis: Development of pheromone-based monitoring of orange wheat blossom midge, Sitodiplosis mosellana (Gehin) (Diptera: Cecidomyiidae)

Examining Committee: Chair:

Dr. G. Gries, Professor, Senior Supervisor Department of Biological Sciences, SFU

Dr. B. Roitberg, Professor Department of Biological Sciences, SFU

Dr. Owen Olfert, Research site manager Agriculture and Agri-Food Canada Saskatoon Research Center, Saskatoon, Saskatchewan

Dr. Sheila Fitzpatrick, Research Scientist Agriculture and Agri-Food Canada Pacific Agri-Food Research Center, Agassiz, B.C. Public examiner

Date Approved: / I SIMON FRASER UNIVERSITY

PARTIAL COPYRIGHT LICENCE

The author, whose copyright is declared on the title page of this work, has granted to Simon Fraser University the right to lend this thesis, project or extended essay to users of the Simon Fraser University Library, and to make partial or single copies only for such users or in response to a request from the library of any other university, or other educational institution, on its own behalf or for one of its users.

The author has further granted permission to Simon Fraser University to keep or make a digital copy for use in its circulatin g collection.

The author has further agreed that permission for multiple copying of this work for scholarly purposes may be granted by either the author or the Dean of Graduate Studies.

It is understood that copying or publication of this work for financial gain shall not be allowed without the author's written permission.\

Permission for public performance, or limited permission for private scholarly use, of any multimedia materials forming part of this work, may have been granted by the author. This information may be found on the separately catalogued multimedia material and in the signed Partial Copyright Licence.

The original Partial Copyright Licence attesting to these terms, and signed by this author, may be found in the original bound copy of this work, retained in the Simon Fraser University Archive.

W. A. C. Bennett Library Simon Fraser University Burnab y, BC,Canada 1lI

ABSTRACT

The orange wheat blossom midge, Sitodiplosis mosellana (Gehin) (Diptera:

Cecidomyiidae), is the key insect pest of spring wheat in North America. My research objectives were: 1) to assess parameters suitable for attracting and trapping male S. mosellana; and 2) to test predictive capabilities of pheromone-baited traps for crop damage. Green Delta traps affixed to stakes about 50 em above ground and baited with polyurethane type pheromone dispensers loaded with 50 ug of stereoisomeric 2,7­ nonanediyl dibutyrate produced in a 2-step synthesis were suitable parameters for capturing male S. mosellana. In wheat-on-wheat fields, we found positive significant relationships between percent of damaged kernels at harvest and captures of male S. mosellana cumulated (a) between the onset of flight and 1-4 days after the heading stage of wheat plants, or (b) between 5 days before and 1-3 days after the heading stage.

Numbers of overwintering larvae in soil were positively correlated with numbers of larvae per wheat head two weeks after anthesis of wheat plants, but not with percent of damaged kernels at harvest. A significant positive relationship was found between numbers of larvae per wheat head two weeks after anthesis and percent of damaged kernels at harvest. In wheat-on-nonwheat fields, no positive correlations were found between any criteria (see above). IV

DEDICATIE

Dedic aceasta lucrare familiei mele care mi-a fost alaturi pe tot parcursul vietii si cercetatorilor de la Institutul de Cercetari si Amenajari Silvice - Statiunea Brasov,

Romania, care mi-au dat incredere si mi-au indrumat pasii la inceputul carierei mele,

Ii sunt profund recunoscator sotiei rnele Bogdana, care a lucrat alaturi de mine pe teren si in laborator. In timpul acestui proiect s-a nascut fiica no astra, Mara, careia ii multumesc pentru bucuria sufleteasca pe care mi-o aduce in fiecare zi.

§

I dedicate this thesis to my family members who have supported me every day of my life and to the my former colleagues, researchers from Forest Re search and

Management Institute, Brasov Station, Romania, for their trust and guidance at the beginning of my career.

I am deeply indebted to my wife , Bogdana Mircioiu, who assisted me in the field and in the laboratory. During this project we were blessed with our daughter Mara who is giving us joy every moment of our lives. v

ACKNOWLEDGEMENTS

I would like to express my gratitude to my supervisor, Dr. Gerhard Gries, for his endless support, guidance, patience, and editing of an earlier draft of my thesis. I thank my committee member, Dr . Owen Olfert from Agriculture and Agri-Food Canada,

Saskatoon Research Center, for his advice and field support. I enjoyed joining his laboratory during two field seasons, learning from, and working with, his knowledgeable staff members Murray Braun and Lori-Ann Kaminski who also collected data for experiments 1-7. I also thank my committee member Dr. Bernard Roitberg for his careful review of my thesis. I am grateful to Regine Gries and Dr. Grigori Khaskin who were always there to listen to my stories, prepared the pheromones, and helped me produce the sticky inserts for the traps. I am indebted to my research assistants Bogdana Mircioiu,

Adela Danci, Dorin Danci, and Ion Molnar, for enduring the mo squitoes, the cold or hot weather of the prairies and the long hours of work. Special thanks go to my fellow students from the "Gries-lab" and MPM program who made graduate studies at SFU an inspirational academic experience. I am thankful to farmers from Saskatchewan near

Dundurn, Kamsack, Maidstone, Brandon, Marshal, Mikado, Veregin, Runnymede and

S askatoon, and from Alberta in or near Paradise Valley, Manville and Vermilion for allowing me to conduct the experiments on their land. I thank the agrologists Jim Broatch,

Stewart Brandt, Tim Nerbas, Wally Vanin and the private consultant Josie Van Lent who helped me find coll aborating farmers for my project.

This research was financially supported by a Graduate Research in Engineering and Technology (GREAT) Scholarship from the Science Council of British Columbia VI with contingent industrial support from Phero Tech Inc., by a Matching Investment

Initiative Grant from Agriculture and Agri-Food Canada with Phero Tech Inc. as the industrial sponsor, and by research grants from the Natural Sciences and Engineering

Research Council of Canada. VII

TABLE OF CONTENTS APPROVAL ii ABSTRACT iii DEDICATIE iv

ACKNOWLEDGEMENTS V TABLE OF CONTENTS vii LIST OF TABLES viii LIST OF FIGURES ix 1 INTRODUCTION 1 1.1 Biology of Sitodiplosis mosellana 1 1.2 Damage and Economic Impact 2 1.3 Current Tactics to Monitor and Control S. mosellana Populations 5 1.4 Objectives 9 2. FIELD TESTING PARAMETERS FOR PHEROMONE-BASED ATTRACTION AND TRAPPING OF MALE Sitodiplosis mosellana 10 2. 1 Introduction 10 2.2 Materials and Methods 12 2.3 Results 18 2.4 Discussions 23 3. DEVELOPMENT OF PHEROMONE-BASED MONITORING OF Sitodipl osis mosellana POPULATIONS 3 1 3.1. Introduction 31 3.2 MateriaJs and Methods 33 3.3 Results 35 3.3. 1 Wheat-on-wheat fields 35 3.3.2 Wheat-on-nonwheat fields 38 3.4 Discussion 48 REFERENCES 51 viu

LIST OF TABLES

Table 1. Total number of male Sitodiplosis mosellana captured in six pheromone­ baited green Delta traps in each of 27 wheat-on-wheat fields in Saskatchewan in 2002, and mean percent captures in two traps placed along each of row (Figure 4) 28 2 Table 2. For wheat-on-nonwheat fields, coefficients of determination (r ) and associated probabilities (P) between numbers of male Sitodiplosis mosellana captured in pheromone-baited traps and percent damaged kernels at harvest, in relation to the period during which trap captures were recorded. All data transformed by log, (x+1), except for percentage of damaged kernels transformed by arcsine J; prior to analysis 47 ix

LIST OF FIGURES

Figure 1. The life cycle of Sitodiplosis mosellana © Glogoza 2003, by permission 3 Figure 2. Forecast of wheat midge in Alberta and Saskatchewan for 2002 (Hartley et al. 200 1) © AAFC - Saskatoon Research Center, by permission 6 Figure 3. Green Delta trap (Phero Tech Inc., Delta, BC) affixed to the top of a pole - 40 cm above ground 13 Figure 4. Trap (Ll) deployment; three rows oftwo traps each were set up perpendicular to the edge of fields, with the central row along the field's middle transect, and side rows 100 m apart from it. Traps within the same row were 15-20 m apart...... 16 Figure 5. Mean (+SE) number of male Sitodiplosis mosellana captured in experiment 2 in Wing traps baited with three types of pheromone dispensers each impregnated with 50 ug of stereoisomeric 2,7-nonanediyl dibutyrate produced in a 5-step synthesis. Wheat-cultivated field near Dundurn, Saskatchewan. In each experiment, bars with different letter superscripts are significantly different, a = 0.05 19 Figure 6. Mean (+SE) number of male Sitodiplosis mosellana, or nontarget insects, captured in experiment 3 in Delta or Wing traps, unbaited or baited with a filter paper dispenser impregnated with 50 pg of stereoisomeric 2,7-nonanediyl dibutyrate produced in a 5-step synthesis. Wheat-cultivated field near Dundurn, Saskatchewan. Bars with different letter superscripts are significantly different, a = 0.05 21 Figure 7. Mean (+SE) number of male Sitodiplosis mosellana captured in experiment 4 in Wing traps placed 15,35, or 55 cm above ground and baited with 50 ug of stereoisomeric 2,7-nonanediyl dibutyrate produced in a 5-step synthesis. Wheat­ cultivated field near Dundurn, Saskatchewan. Bars with different letter superscripts are significantly different, a = 0.05 24 Figure 8. Mean (+SE) number of male Sitodiplosis mosellana captured in experiment 1 in green Delta traps baited with polyurethane-based pheromone dispensers loaded with 50 pg of stereoisomeric 2,7-nonanediyl dibutyrate produced in a 2-step or 5-step synthesis. Wheat field near Maidstone, Saskatchewan. Bars with the same letter superscripts are not significantly different; a = 0.05. The amount of active ingredient, (S,S)-2,7-nonanediyl dibutyrate, was identical in each lure 26 Figure 9. Relationships in 27 wheat-on-wheat fields in 2002 between (A, B) extrapolated numbers of cocooning Sitodiplosis mosellana larvae per m2 of soil per field and (A) the mean number of larvae per wheat head per field, or (B) percent damaged kernels per field; and between mean numbers of larvae per wheat head per field and percent damaged kernels per field (C). Spearman correlation coefficients x

(rs), or coefficient of determination (r\ and probability levels (P) are given for each relationship. All data transformed by log, (x+1), except for percentage of damaged kernels transformed by arcsine .j; prior to analysis 36 Figure 10. Relationship in 14 wheat-an-wheat fields in 2002 between cumulative numbers of male Sitodiplosis mosellana captured in pheromone-baited traps and the percentage of damaged kernels at harvest. Captures were recorded between the onset of the S. mosellana flight and one, two, three, four and five days after the heading stage of wheat plants. Captures of males transformed by log, (x+1) and percentage of damaged kernels transformed by arcsine .j; prior to analysis. At the time of trap placement, 13 out of 27 wheat-an-whet fields were already approaching the heading stage, and thus were not included in this analysis 39 Figure 11. Relationship in 12 wheat-an-wheat fields in 2002 between cumulative numbers of male Sitodiplosis mosellana captured in pheromone-baited traps and the percentage of damaged kernels at harvest. Captures were recorded over a period of time starting five days before the heading stage of wheat plants until one, two, three, four and five days after the heading stage of wheat plants. Captures of males transformed by log- (x+1) and percentage of damaged kernels transformed by arcsine .j; prior to analysis. At the time of captures recording, 15 out of 27 wheat-an-whet fields were already approaching the heading stage, and thus were not included in this analysis 41 Figure 12. Relationship in 27 wheat-an-wheat fields in 2002 between mean cumulative captures of male Sitodiplosis mosellana in pheromone-baited traps and the percentage of damaged kernels at harvest. Captures were recorded over a period of time starting at the heading stage of wheat plants and one, two, three, four and five days thereafter. Captures of males transformed by log- (x+1) and percentage of damaged kernels transformed by arcsine .j; prior to analysis...... 43 Figure 13. Relationship in 22 wheat-on-nonwheat fields near Kamsack (Saskatchewan) in 2002 between (A, B) extrapolated numbers of cocooning Sitodiplosis mosellana larvae in 1 m 2 of soil in the adjacent fields cultivated with wheat in 2001 and mean numbers of larvae per wheat head per field (A) , or percent damage kernels at harvest per field (B) , and (C) between mean numbers of larvae per wheat head per field and percent damaged kernels at harvest. Spearman correlation z), coefficients (rs), or coefficients of determination (r and probability levels (P) are given for each relationship. All data transformed by IOg2 (x+ 1), except for percentage of damaged kernels transformed by arcsine .j; prior to analysis...... 45

- 1 INTRODUCTION

1.1 Biology of Sitodiplosis mosellana

The orange wheat blossom midge, Sitodiplosis mosellana (Gehin) (Diptera:

Cecidomyiidae), is widely distributed around the world wherever wheat is grown

(Helenius and Kurppa 1989) . The midge was introduced into North America with early

European settlers, and first reported in Quebec in 1828 (Felt 1921 cited by Mukerji et al.

1988). By the early 1980s, it had become a key pest of spring wheat in western Canada

(Olfert et al. 1985) with widespread outbreaks in Saskatchewan and Manitoba (Barker et aJ. 1995).

Sitodiplosis mosellana is univoltine and short-lived (Barnes 1953). Adults (2-3 mrn in length) eclose in late June or early July (Mukerji et aJ. 1988) . Protandrous males may eclose several days before females (Pivnik and Labbe 1992), with a sex ratio eventually approaching 2 : 3 (0' : ~ ) (Lamb 2002; personal communication). Sexual communication and mating take place when the air temperature is > ] 5°C and the wind speed < 10 kmJh. To attract a male, females emit a sex pheromone (Pivnik and Labbe

1992; Pivnik 1993) , identified as (2S, 7S)-nonanediyl dibutyrate (Gries et aJ. 2000).

Mated females lay eggs singly or in groups of three to five on pre-flowering wheat heads, underneath the glume or the palea (Mukerji et al. 1988). On average, a female can lay 83.6 eggs over a 6-day period (Pivnik and Labbe 1993). Larvae hatch ca. 5 days later (Olfert et al. 1985) and feed on developing kernels for ca. 2-3 weeks. Mature 2 larvae remain quiescent in the wheat head, protected by a sheath-like skin (Mukerji et al.

1988). They exit heads that are moistened by rain , and burrow into the upper soil where they form overwintering cocoons (Olfert et al. 1985, Mukerji et al. ]988). In late spring of the next year, when soil-moisture conditions permit, larvae break diapause and move to the soil surface to pupate (Figure I).

Sitodiplosis mosellana can develop on wheat, rye and barley (Wright and Doane

1987). Both common (bread) wheat, Triticum aestivum L., and durum (pasta) wheat,

Triticum durum Desf. (Gramineae), are the principal hosts for S. mosellana (Smith and

Lamb 2001, Wright and Doane 1987) .

1.2 Damage and Economic Impact

Sitodiplosis mosellana greatly contribute to reduced yield of spring wheat in

Canadian prairies (Olfert et al. 1985). In addition, kernels fed on by larvae are inferior in milling quality and germination capacity (Miller and Halton] 96]). Grain yield decreases exponentially with the increase in larval infestations (Olfert et al. ]985). Infestations of

S. mosellana are also correlated with the presence of wheat scab, Fusarium graminearum, and glume blotch, Septoria nordorum (Berk.), suggesting that adults vector fungal spores

(Mongrain et al. ]997).

Several outbreaks of S. mosellana have been reported in North America since this exotic insect pest became established in 1800. Past population outbreaks in Quebec,

Nova Scotia and the Eastern USA (Lamb 2001), and more recent outbreaks in 3

Figure 1. The life cycle of Sitodiplosis mosellana © GJogoza 2003, by permission. Life Cycle of Orange Wheat Blossom Midge .l Sitodiplosis mosellana

adult

@ Larva- drop from heads after @ rain or heavy dew

cocoon larva o o cocoon o c@lIllllID o May ~une ~uly August

+:>- 5

Saskatchewan, Manitoba, Alberta, North Dakota, and Minnesota, have resulted in multi­ million dollar losses (Felt 1921, Reeher et al. 1945, Barnes 1956) . In 1983, for example,

S. mosellana reached epidemic populations in northeastern Saskatchewan, causing revenue losses of $30 million in the infested area (Olfert et al. 1985). Since then, S. mosellana populations have spread across the wheat-growing area of the Northern Plains

(Figure 2). In 1995, yield losses in Saskatchewan reached 30% in many fields and averaged 15% in the Red River Valley of North Dakota and Minnesota (Lamb et al.

1999). In the same year, total losses exceeded $50 million in Manitoba and $100 million in Saskatchewan. In North Dakota in 1995, wheat producers lost an estimated 7 million bushels in wheat yield, and $30 million in gross revenue due to S. mosellana. (K. McKay and P. Glogoza, personal communication).

1.3 Current Tactics to Monitor and Control S. mosel/ana Populations

Careful monitoring of wheat fields is required to identify S. mosellana infestations and to take appropriate control measures. Current assessments of S. mosellana populations are time-consuming, tedious and not user-friendly. These tactics include soil sampling for larvae, captures of adults in colored sticky traps, and recording numbers of eggs , larvae or adults on heads of wheat (Mukerji et al. 1988, Oakley et a1.

1994, Lamb et a1. 2002). Soil sampling provides information about population levels and percent parasitism. Colored traps afford many by-catches that are not readily distinguished from S. mosellana adults. Counts of eggs are laborious and require the use of a stereomicroscope. Counts of adults on wheat heads must be conducted in the evening and are confounded by the presence of "midge look-a-like" insects. Even though an 6

Figure 2. Forecast of wheat midge in Alberta and Saskatchewan for 2002 (Hartley et al.

2001) © AAFC - Saskatoon Research Center, by permission. at Mid eF recast 2002 L J/fl \) /-L .L-.I f-,_ \ i- "- \ ~~ .~ J ~ 'I ' .,' , '\

~ \

Midge per sq uare meter D No infestati on D < 600 D 600 <= 1200 I' l '-,""" 1200 < = 1800 f ~\-~,J ~ > 1800 I--:J-l rl _L.. --.) 8

action-threshold of one adult per four to five wheat spikes has been established

(Anonymous 1993), decisions are made with little confidence because no relationship has

been detected between the number of adults in the crop and subsequent densities of larvae

or damaged kernels (Oakley et al. 1998). Uncertain about their S. moseLlana population assessment, wheat producers often decide to apply unnecessary and costly "insurance sprays". Moreover, ill-timed insecticide applications are not cost-effective, environmentally unacceptable, and adversely affect biological control agents.

Cultural, biological and chemical control tactics are employed to manage S. mosellana populations. Cultural practices include crop rotation to non-preferred crops, seeding early or late (Knodel 1998), and selecting varieties with early seed maturation or antibiotic resistance to the larvae. Wheat cultivars resistant to S. mosellana would result in long-term reduction of damage (Barker and McKenzie 1996, Lamb et al. 2000), but are not yet available. Various biological control agents, such as spiders, mites, carabids and hymenopterous parasitoids, prey upon S. mosellana populations, but significant crop damage still occurs (Doane et al. 1989, Floate et al. 1990, Harris 1996). Insecticides remain the primary means of controlling S. mosellana. A single, well-timed application of an insecticide suppresses adult populations, improves crop yield, and increases the farmers' profit (Elliott 1998). 9

1.4 Objectives

My research objectives were:

1) to determine parameters (pheromone source, pheromone dispenser, and

vertical position of trap) suitable for a trapping system to be deployed for

pheromone-based monitoring of S. mosellana populations; and

2) to investigate whether captures of male S. mosellana in pheromone-baited

trap s are correlated with estimates of population densities and damaged

wheat kernels at harvest. 10

2. FIELD TESTING PARAMETERS FOR PHEROMONE­ BASED ATTRACTION AND TRAPPING OF MALE Sitodiplosis mosellana

2.1 Introduction

Pheromone-baited traps are an ideal tool for monitoring insect populations. The

technology is selective, user friendly and inexpensive (Wa111989), and works at low population densities. The efficacy of pheromone trap technology is based on the attractant(s), attractant dispenser, trap type and trap placement.

(25,75) - Nonanediyl dibutyrate constitutes the sex pheromone of 5. mosellana

(Gries et al. 2000), but a stereoisomeric mixture of all four stereoisomers (including the pheromone) is equally effective as a trap bait (Gries et al. 2000). However, synthesis even of the stereoisomeric mixture is prohibitively expensive and prompted development of a

2-step commercial synthesis (Khaskin et aI., unpublished). The end product of the commercial synthesis ("commercial pheromone") contained undesired contaminants, and thus needed to be field tested for its attractiveness.

Release characteristics of pheromones depend upon the dispenser type and materials, which may be based on filter paper, rubber septa, polyurethane, polyethylene, polyvinyl chloride or hollow fibers. Experiments were conducted to determine release rates of pheromone, or captures rates of insects, over the period of time traps were deployed in the field. For example, Wall and Greenway (1981) and Sanders (1984) 11 demonstrated consistent trap captures of Cydia nigricana when pheromone dispensers consisted of rubber or lactic capsules, whereas Bakke et al. (1983) concluded that lure attractiveness for the European spruce beetle, Ips typographus, had decreased to 50 % after 5-6 weeks of lure deployment.

Traps used for pheromone-based insect monitoring should be practical, efficient, inexpensive, and easy to examine and/or to empty (Wall 1990). Most types of monitoring traps hav e a simple design with sticky plates or strips to retain attracted insects.

Moreover, traps should minimize captures of non-target "by-catches" that may be difficult to discern from target insects, may complicate recordings of target insects, or may saturate a sticky traps' surface.

Trap placement (vertical position in vegetation) affects captures of target insects.

Traps should be placed at a height to maximize captures of insects, unless it is more practical to do otherwise (Wall, 1990). When practical versus most effective trap placement were compared (e.g. Miller and McDougal 1973, Sanders 1978), practical placement was preferred unless most effective placement was required to predict crop damage. Placement of pheromone-baited traps at crop canopy would be most practical for capturing male S. mosellana, although more males might be captured if traps were placed near the ground where adults emerge (Mukerji et al. 1988).

The number of traps per area and trap spacing also affect trap captures, and thus warrant consideration in the development of insect monitoring programs. 12

My objective in this chapter was to assess parameters of the trapping system, including the quality of the synthetic pheromone, the pheromone dispenser and trap type, trap placement, and number of traps per field .

2.2 Materials and Methods

All field trapping experiments were conducted in Saskatchewan in fields cultivated with spring wheat. Traps were set up in a complete randomized design at 10-15 m intervals in a single line 10 m from and paralleling the field's margin.

Experiment 1 tested the hypothesis that traps baited with filter paper, rubber septum or polyurethane-based pheromone dispenser differ in their attractiveness to male

S. mosellana . Near the community of Dundurn (Saskatchewan, 51 ° 49' 00" N - 106° 30'

00" W), 40 wing traps with sticky inserts (Phero Tech Inc.) were suspended from a bamboo stick - 20 ern above ground. Traps were baited with a filter paper (Whatman

International Ltd., Maidstone, England), rubber septa (The West Company, Lionville,

Pennsylvania), or polyurethane-based dispenser (Phero Tech Inc.) each impregnated with

50 ug of synthetic "5-step pheromone", or left unbaited. After 3 nights of trapping (14-16

Jul y 2000), the experiment was terminated and the number of male S. mosellana captured was recorded.

Experiment 2 tested the hypothesis that white Wing traps (Phero Tech Inc.) with their greater apparency and larger opening for insect entry than green Delta traps (Phero

Tech Inc.) capture both the most male S. mosellana , and nontarget insects. Near Dundurn

20 Wing traps and 20 Delta traps were suspended from bamboo poles 20 em 13

Figure 3. Green Delta trap (Phero Tech Inc., Delta, Be) affixed to the top of a pole - 40 em above ground. 14 15

above ground and baited with a filter paper dispenser impregnated with 50 u g of synthetic 5-step pheromone, or left unbaited. After 3 nights of trapping (14-17 July 2000), the experiment was terminated, and number of captured male S. mosel/ana recorded.

Experiment 3 tested the hypothesis that the vertical trap position (15,35 or 55 ern above ground) affects captures of male S. mosel/ana. Near Dundurn, 30 Wing traps were suspended from bamboo poles at 15,35, or 55 em above ground and baited with filter paper impregnated with 50 ug of synthetic 5-step pheromone. After 4 nights of trapping (20-24 July 2000), the experiment was terminated and the number of captured male S. mosellana recorded.

Experiment 4 tested the hypothesis that synthetic pheromones produced either via a 5-step synthesis ("5-step pheromone") or a 2-step commercial synthesis ("2-step pheromone) are equally attractive to male S. mosellana. In a field near the community of

Maidstone (Saskatchewan, 53° 06' 00" N - 109° 17' 00" W), 30 green Delta traps with white insert (Phero Tech Inc., Delta, BC) were affixed to the top of poles - 40 em above ground (Figure 3). Traps were baited with polyurethane-based dispensers loaded with 100 ug (active ingredient) of 2- or 5-step synthetic pheromone, or left unbaited (control).

Captures of male S. mosellana were recorded without changing inserts at 3- to 4-day intervals between 24 July and 11 August 2001.

Experiment 5 tested the null hypothesis that the position of Green Delta traps within a field does not affect captures of male S. mosellana. In each of 27 fields, three rows of two traps each were set up perpendicular to the edge of fields with the central row along the fields' middle transect, and side rows 100 m apart from it (Figure 4). Within 16

Figure 4. Trap (L1) deployment; three rows of two traps each were set up perpendicular to

the edge of fields, with the central row along the field's middle transect, and

side rows 100 m apart from it. Traps within the same row were 15-20 In apart. 17

E o N coI

~ / E o o ..- ~ -:

E o o ..- -- ~ 18

rows, traps were 15-20 m apart and baited with polyurethane-based dispensers

impregnated with 100 ug of 2-step pheromone. The white sticky inserts in all traps were

replaced and captured male S. mosellana recorded every 3, 4 or 5 days between 1 July to

15 August 2002.

Trap-catch data in all experiments were analyzed by Anova and means compared

by the Tukey-Kramer test, using software package JMP IN Version 4 (SAS Institute Inc.).

In all experiments, a. = 0.05.

2.3 Results

In experiment 1, traps baited with filter paper type pheromone dispensers captured significantly more male S. mosellana than those baited with polyurethane- or

rubber septa-based pheromone dispensers, with the latter two types equalJy effective in attracting male S. mosellana (F=9.2241, df=3, 36, P=O.OOOI) (Figure 5) . These results support the hypothesis that pheromone dispenser types differ in their attractiveness to target insects.

In experiment 2 as hypothesized, Wing traps were significantly more effective

than Delta traps in capturing male S. mosellana, and baited Wing or Delta traps captured significantly more male S. mosellana than unbaited traps of either type (F=43.1713, df=3,

36, P

(F=13.4020, df=3, 35, P

Figure 5. Mean (+SE) number of male Sitodiplosis mosellana captured in experiment 2

in Wing traps baited with three types of pheromone dispensers each

impregnated with 50 ug of stereoisomeric 2,7-nonanediyl dibutyrate produced

in a 5-step synthesis. Wheat-cultivated field near Dundurn, Saskatchewan. In

each experiment, bars with different letter superscripts are significantly

different, a = 0.05 .

L 20

"0 (1) l- :::J a Q.eo 80 o C/) (1) E 60 \I-o l- (1) .0 E 40 :::J C w-- if) 20 -.-+ c ro (1) c ~ Filter Polyurethane Rubber unbaited paper septum Type of pheromone dispenser 21

Figure 6. Mean (+SE) number of male Sitodiplosis mosellana, or nontarget insects,

captured in experiment 3 in Delta or Wing traps, unbaited or baited with a filter

paper dispenser impregnated with 50 ug of stereoisomeric 2,7-nonanediyl

dibutyrate produced in a 5-step synthesis. Wheat-cultivated field near Dundum,

Saskatchewan. Bars with different letter superscripts are significantly different,

a = 0.05. 22

"'0 <1> ~ a :J 0.120 ro o en <1> 100 ro E 80 I+- 0 ~ 60 <1> ..0 E 40 :J e --w 20 U) c ...... + 0 e Wing Wing Delta Delta ro <1> (baited) (unbaited) (baited) (unbaited) 2

30 "'0 -.-<1> a o :J 25 <1>0..~ -- ..oro E o 20 :Jenen w~ 15 (/) .~ +.- -; ~10 ro ~ <1>19 2 t: 5 o e o Wing Wing Delta Delta (baited) (unbaited) (baited) (unbaited)

Trap type 23

In experiment 3, Wing traps 55 ern above ground captured significantly more

male S. mosellana than those] 5 or 35 em above ground, with the later two vertical

positions equally effective (F=] 1.7972, df=2, 27, P=O.0002) (Figure 7). These data

support the hypothesis that captures of S. mosellana are dependent on the vertical position

of traps.

In experiment 4 as hypothesized, traps baited with 2- or 5-step synthetic

pheromone captured similar numbers of male S. mosellana (F=26. I 503, df=2, 27,

P

In experiment 5 (Table 1), a similar percentage of male S. mosellana was captured in Delta traps on central and side rows (Figure 4) .

2.4 Discussions

Results obtained in experiments 1-5 facilitated decisions about pheromone purity, dispenser and trap type, vertical trap placement, and numbers of traps per field to be deployed for development of pheromone-based monitoring of S. mosellana populations.

Direct comparison of pheromone produced by a 2- and 5-step synthesis revealed no difference in attractiveness (a = 0.05) (Figure 5), indicating that contaminants in the 2­ step synthetic product had no adverse effect and that large scale synthesis of pheromone for trap lures will be cost-effective. Although the filter paper type pheromone dispenser afforded higher trap captures than other dispenser types (Figure 6), filter paper lures are not suitable for mass manufacturing, and thus will not be considered for 24

Figure 7. Mean (+SE) number of male Sitodiplosis mosellana captured in experiment 4 in

Wing traps placed 15,35, or 55 em above ground and baited with 50 ug of

stereoisomeric 2,7-nonanediyl dibutyrate produced in a 5-step synthesis. Wheat­

cultivated field near Dundurn, Saskatchewan. Bars with different letter

superscripts are significantly different, a = 0.05. 25

"0 Q) 1- :::J 35 .....a. a co o 30 en Q) 25 co E 20 I+- 0 1- Q) 15 .a E 10 b :::J c b w--- 5 (f) ...-+ a c 15 em 35 em 55 em ro Q) ~ Vertical position of traps above ground 26

Figure 8. Mean (+SE) number of male Sitodiplosis mosellana captured in experiment] in

green Delta traps baited with polyurethane-based pheromone dispensers loaded

with 50 ug of stereoisomeric 2,7-nonanediyl dibutyrate produced in a 2-step or

5-step synthesis. Wheat field near Maidstone, Saskatchewan. Bars with the

same letter superscripts are not significantly different; a = 0.05. The amount of

active ingredient, (S,S)-2,7-nonanediyl dibutyrate, was identical in each lure. 27

"0 a 0) ~ ::J 80 a +-' 0-ro 0 en 0) 60 ro E '+- 0 40 ~ ()) .0 E ::J c 20 -w (f) b + a c --ro 5-step 2-step unbaited 0) synthetic synthetic ~ pheromone pheromone Treatment 28

Table 1. Total number of male Sitodiplosis mosellana captured in six

pheromone-baited green Delta traps in each of 27 wheat-an-wheat

fields in Saskatchewan in 2002, and mean percent captures in two traps

placed along each of row (Figure 4).

Percent captures in Field number Total captures Row 1 Row2 Row3 2 550 26 48 26 3 331 23 53 24 4 1172 35 22 43 5 834 32 28 39 6 617 31 33 36 7 589 26 34 41 12 890 37 29 34 14 1064 43 26 32 17 1296 33 39 28 19 981 33 31 36 23 805 32 44 24 25 230 17 35 48 35 843 43 30 28 36 809 51 46 3 37 1548 37 37 26 38 1753 26 44 29 39 484 33 37 30 40 1686 33 44 23 42 1228 29 - 26 45 44 693 19 33 48 46 967 38 30 32 48 353 22 45 33 49 450 61 8 31 50 570 32 44 24 51 525 37 19 45 52 623 41 27 33 53 493 22 46 32 Mean 829 33 35 32 Coefficient of variation (%) - 29.19 29.23 29.82 29 commercialization. Cost efficient mass-manufacturing of monitoring lures is critical in light of thousands of farmers in Canada and the United States who might adopt pheromone-based monitoring of S. mosellana. In experiment 2, captures of male S. mosellana were not significantly different in traps baited with polyurethane or rubber type pheromone dispensers (Figure 6). These results contrast with those in other studies. In studies with nun moth, Lymantria monacha, e.g., polyurethane-based dispensers were superior to rubber septa in attracting males (Morewood et aJ. 2000). Similarly, in studies with mullein bugs, Campylomma verbasci, polyurethane-based pheromone dispensers were found to have excellent release rate characteristics and cost-efficiency, and were thus recommended for operational monitoring of C. verbasci populations (McBrien et aJ.

1994).

Wing traps required less handling time in the field than Delta traps (Knodel and

Agnello 1990) , and captured more S. mosellana than Delta traps (Figure 7), but afforded significantly higher captures of nontarget insects (Figure 7). Considering that the absolute number of target insects in traps is not critical in monitoring programs, and that numerous nontarget insects in traps complicate or confound trap catch recordings (particularly to nonexperienced personnel), Delta traps seem most suitable for the development of pheromone-based monitoring of S. mosellana populations. Saturation of sticky trap surfaces with insects (e.g . Morewood et al. 2000, Brown 1984, Sanders 1986) would not be a concern in monitoring programs of S. mosellana populations, because male S. mosellana are very small, and would not readily saturate trapping surfaces. Moreover, sticky Delta traps have been recommended for monitoring another tiny fly, the Douglas- 30 fir cone gall midge, Contarinia oregonensis (Diptera: Cecidomyiidae), in seed orchards

(Morewood et al. 2002).

That most male S. mosellana were captured in traps 55 em above ground is surprising in light of reports that mating takes places near the ground (Mukerji et al.

1988). Considering that trap placement at or above crop canopy facilitates recording of trap captures, traps will be placed at a height of 55 em for the development of pheromone-based monitoring of S. mosellana populations (Chapter 3).

Captures of male S. mosellana seemed unaffected by the within-field position of traps, because mean captures and coefficients of variation (%) were similar for each row

(Table 1; Figure 4) . This conclusion is supported by findings that similar numbers of adult S. mosellana were captured in emergence traps placed 1, 50, or 100 m from the edge of fields (Lamb et al. 1999). My results suggest that two traps in a grid pattern (Figure 4) are sufficient for the development of pheromone-based monitoring of S. mosellana populations.

In conclusion, experiments in chapter 2 helped determine parameters suitable for pheromone-based attraction and trapping of male S. mosellana. Six green Delta traps baited with polyurethane-based dispensers impregnated with 50 ug of "2-step" stereoisomeric pheromone and affixed to poles at crop canopy (-55 em above ground), and seem most appropriate. These parameters can now be implemented for the development of pheromone-based monitoring of S. mosellana populations (Chapter 3). 31

3. DEVELOPMENT OF PHEROMONE-BASED MONITORING OF Sitodiplosis mosellana POPULATIONS

3.1. Introduction

Pheromone-based monitoring relies on quantitative relationships between trap- captured insects and population densities, which facilitate assessment of population trends and consequent management deci sions (Campion 1984; Wall 1990). Pheromone-based monitoring is species-specific, relatively inexpensive, easily deployed, applicable over a wide range of population sizes , and may be operated by nonentomologists (Elkinton and

Carde 1981; Wall 1990; Grant 1991).

Pheromone-based monitoring is widely used for Lepidoptera (Grant 1991).

Quantitative relationships between captures of male moths in pheromone-baited traps and estimates of population densities, or crop damage, have been found for eastern spruce budworms, Choristoneura fumiferana (Clemens.) (Sanders 1988) , western hemlock loopers, Lambdia fiscellaria lugubrosa (Hulst) (Even den et al. 1995) , nun moths,

Lymantria monacha (L. ) (Morewood et al. 2000), European corn borers, Ostrinia nubilis

(Hubner) (Ngolo et al. 2000), and pink bollworms, Pectinophora gossypiella (Qureshi et al. 1993).

Pheromone-based monitoring has also been developed for mealybugs,

Planococcus ficus (Signoret) (Homoptera: Pseudococcidae) (Millar et al. 2002), mullein bugs, Campylomma verbasci (Meyer) (Heteroptera: Miridae) (McBrien et aI. 1994) , and 32 spruce bark beetles, Ips typographus (L.) (Coleoptera: Ipidae) (Weslien 1992), indicating that this technology is applicable to pest insect populations from diverse orders.

Within the family Cecidomyiidae (Diptera), sex pheromones have been identified for the Hessian fly, Mayetiola destructor (Say) ( Foster et al. 1991), pea midge,

Contarinia pisi (Winnertz) (Wall 1985, Hillbur et al. 2000, Hillbur 2001), S. mosellana

(Gries at al. 2000), C. oregonensis (Foote) (Gries et al. 2002), and the aphidophagous gall midge Aphidoletes aphidimyza (Rondi) (Choi et al. 2004).

Morewood et al. (2002) developed a pheromone-based monitoring system for C. oregonensis that consists of Wing or green Delta traps baited with 50 IJg of pheromonal racemic (Z,Z)-4,7-tridecadien-2-yl acetate in a polyurethane-based dispenser. Deploying

20 traps per orchard block, Morewood et al. found positive correlations between numbers of males captured in traps and numbers of both egg-infested and galled scales. The authors determined that captures of four and two male C. oregonensis in Wing and Delta traps, respectively, may warrant insecticidal control.

For monitoring S. mosellana populations, Doane et a!. (2000) developed sequential sampling for overwintering larvae, concluding that 6 cocoons per 100 cm 2

"might produce an economic infestation". However, the authors also concluded that even

"if cocoon populations indicate that a significant number of adults and eggs may occur the next crop year, adult populations and weather during the susceptible stage of wheat crop (Elliott and Mann 1996) need to be closely monitored".

In 1985, Olfert et al. recorded a positive correlation coefficient between numbers of larvae per wheat kernel and percent kernels with larval damage at harvest. This 33

quantitative relationship, however, can not be used for management decisions, because

larvae feeding on kernels can not be killed by insecticide applications. Research

conducted by Lamb et al. (2002) revealed that numbers of S. mosellana larvae per wheat

head , or percentage of infested seeds, were correlated with the numbers of adults on 10

yellow sticky cards (77 x 125 mm) affixed to stakes at the height of wheat heads.

With the pheromone of S. mosellana identified (Gries et al. 2000), commercial pheromone synthesis developed (Khaskin et a!. unpublished), and assessments of pheromone quality, dispenser type, as well as trap type and placement complete (Chapter

2), the development of pheromone-based monitoring of S. mosellana populations has become feasible.

My objective in Chapter 3 was to study the potential for pheromone-based monitoring of S. mosellana populations by investigating the relationships between captures of males in pheromone-baited traps and estimates of population densities and crop damage at harvest.

3.2 Materials and Methods

Experiments were conducted near Kamsack (51 0 34' 00" N - 101 0 54' 00" W) , eastern Saskatchewan, in rural municipalities 271,273 and 301 in fields cultivated with wheat-on-wheat (wheat the preceding and current year) and wheat-on-nonwheat (no wheat the preceding year) fields. Wheat-on-nonwheat fields were adjacent to one or more fields cultivated with spring wheat the preceding year. The size of fields varied between

32 and 64 ha. 34

During April and May 2002, 78 fields cultivated with wheat in 2001 were sampled for densities of larval cocoons in the soil. In each field, 10 soil cores at 15-m intervals were collected along a central transect starting from, and perpendicular to, the roadside edge of the field. Soil cores were washed and sieved to remove impurities

(Doane et a1. 1987), and analyzed under a microscope for the presence of overwintering larvae. Larvae with or without cocoons were dissected and checked for the presence of the parasitoid Macroglenes penetrans (Kitby) (Hymenoptera: Pteromalidae). Larvae parasitized by M. penetrans were considered dead and not included in population estimates. Populations estimates per m2 were approximated by multiplying the number of viable S. mosellana larvae with the constant 198, representing the extrapolation factor

2 2 from the surface of the sampler (0.00 5 m ) to 1 m .

From the end of June through early July 2002, six green Delta traps (Figure 2) with replaceable white inserts were deployed in a grid pattern (Figure 4) in fields cultivated with spring wheat in 2001,2002, or in both years. Traps were nailed to the top of poles at a height of 50-55 em, which is at the canopy of mature wheat crops. Sticky inserts were replaced and captures recorded every 3-5 days from early July to late August.

When the traps were checked, the developmental stage of wheat plants was noted, and the onset of the heading in >50% of plants and anthesis stage recorded in all fields with wheat in 2002. Between heading and anthesis wheat plants are susceptible to

S. mosellana (Pivnick 1993, Ding and Lamb 1999). At the time of trap placement, 13 out of 27 wheat-an-wheat fields, and 4 out of 22 wheat-on-nonwheat fields were already approaching the heading stage. 35

Two weeks after anthesis (-late July), all wheat heads were collected from three

wheat plants near each of the two traps in the field's middle transect (Figure 4). Heads

were enclosed in paper bags, and stored at 4°C before kernels were examined for the

presence of larvae. In late August 2002, just before wheat harvest, all wheat heads were collected from three plants near each of the two traps in the field's middle transect

(Figure 4), and stored as described above. During October-December 2002, kernels were examined for larval damage.

Experimental data from wheat-on-wheat and wheat-on-nonwheat fields were processed separately. To correct for non-normal distribution all data were transformed by log, (x+ 1), except for percentage of damaged kernels at harvest which were transformed by arcsine j; (Zar 1999). Relationships between mean numbers of larvae in wheat heads, percent damaged kernels per field, and cumulated trap captures of male S. mosellana were studied by regression analyses (JMP In 4, SAS Institute Inc.). Despite transformation, numbers of larvae in soil were not normally distributed and therefore were subjected to nonparametric Spearman correlation analysis (Zar 1999).

3.3 Results

3.3.1 \Vheat-on-wheat fields

There were significant positive correlations between numbers of soil-cocooning larvae per m2 of soil per field and mean numbers of larvae per wheat head per field

(Figure 9 A), and between mean numbers of larvae per wheat head per field and percent damaged kernels per field (Figure 9 C). There were also no significant correlations 36

Figure 9. Relationships in 27 wheat-on-wheat fields in 2002 between (A, B) extrapolated

numbers of cocooning Sitodiplosis mosellana larvae per m2 of soil per field

and (A) the mean number of larvae per wheat head per field, or (B) percent

damaged kernels per field; and between mean numbers of larvae per wheat

head per field and percent damaged kernels per field (C). Spearman correlation

2 coefficients (rs), or coefficient of determination (r ), and probability levels (P)

are given for each relationship. All data transformed by log» (x+ 1), except for

percentage of damaged kernels transformed by arcsine E prior to analysis. 37

,...... , ,.--.. 3 aJor- cu+ A • 2:.2:S • cu N - 0) • '+-0 2 O=.. • • ~'"O aJ cu ..oaJ I • E.c • :J ...... eCU • e(1) I • cu.c rs = 0.470 (1)3: • • p= 0.016 ~Q) 0 I • Q. 0 2 4 6 8 10 Number of larvae per m2 [I092(x+1)] 20 B • 15 • • 10 • • • t • • •• Q)' • c 5 • (/) • r = 0.347 u s '- • co • p= 0.077 '-'...... (/) 0 Q) • > '- 0 2 4 6 8 10 co .c ...... Number of larvae per m2 [I092(X+1)] ro 20 ----~ 0 '-' C (/) Q) • c 15 • '- Q) .x: U Q) • r» 10 ro E ro 0 • 5- • Y = 3.50x + 3.92 • •• r2 = 0.357 0 •• • P = 0.001 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Mean number of larvae per wheat head per field [I092(x+1)] 38 between numbers of soil-cocooning larvae per m2 of soil per field and percent ofdamaged kernels per field (Figure 9 B). Significant positive relationships were found between percent damaged kernels per field and cumulative captures ofmales from the beginning of the flight season to days 1-4 after the wheat's heading stage (Figure 10). Similarly, there were significant positive relationships between percent damaged kernels per field and cumulative captures of males when captures were considered only for the period starting 5 days before until 1-3 days after the heading stage (Figure 11). No such positive correlation, however, were obtained for the period just 1-5 days after the heading stage

(Figure 12).

3.3.2 Wheat-on-nonwheat fields

There was no correlation between the mean number of larvae per wheat head per field and percent damaged kernels per field (Figure 13 C). There were no significant correlations between numbers of soil-cocooning larvae in the adjacent wheat field the preceding year and either mean numbers oflarvae per wheat head in current year's wheat fields (Figure 13 A), or percent damaged kernels in current year's wheat fields (Figure 13

B).

There were no significant positive correlations between percent damaged kernels per field and cumulative captures of males (Table 2) for the periods encompassing (a) the onset of flight until 1-5 days after the wheat's heading stage, (b) 5 days before until 1-5 days after the heading stage, and (c) 1-5 days after the heading stage 39

Figure 10. Relationship in 14 wheat-on-wheat fields in 2002 between cumulative numbers

of male Sitodiplosis mosellana captured in pheromone-baited traps and the

percentage ofdamaged kernels at harvest. Captures were recorded between the

onset of the S. mosellana flight and one, two, three, four and five days after the

heading stage of wheat plants. Captures of males transformed by leg- (x+ 1)

and percentage of damaged kernels transformed by arcsine j; prior to

analysis. At the time of trap placement, 13 out of 27 wheat-on-whet fields were

already approaching the heading stage, and thus were not included in this

analysis. 40

20,.------, 20..------,

y=1 .62x+4.10 y = 1.84 x + 2.77 2= r2= 0.299 • r 0.316 • • P= 0.037 • 15 P = 0.043 15 Heading time 1 day after heading

10 10 ..-- ~ Q) • • c 5 5 (J) o 1 2 3 4 5 6 7 1 2 3 4 5 6 7 L-rc --...... 20 20 (J) Q) > Y = 2.0 x + 1.73 Y = 2.10 x + 0.92 L- 2= ro r 0.325 • r2= 0.329 • ..c P = 0.033 • ...... 15 15 P = 0.032 • co 2 days after heading ..-- 3 days after heading ~ 0

--(J) Q) 10 10 c L- Q) .Y. -0 Q) • • 0) 5 5 co E 1 2 3 4 5 6 7 1 2 3 4 5 6 7 m 0 20 20

2= y=2.15 x+0.19 r 0.243 2= • P = 0.073 r 0.292 • • • 15 P = 0.046 15 5 days after heading 4 days after heading •• • • • • 10 10 • • • • • • •• • • • 5 5 1 2 3 4 5 6 7 1 2 3 4 5 6 7 Number of males captured [1092 (x+1)] 41

Figure II. Relationship in 12 wheat-on-wheat fields in 2002 between cumulative

numbers of male Sitodiplosis mosellana captured in pheromone-baited traps

and the percentage of damaged kernels at harvest. Captures were recorded over

a period of time starting five days before the heading stage ofwheat plants

until one, two, three, four and five days after the heading stage of wheat plants.

Captures ofmales transformed by l.og2 (x+ 1) and percentage ofdamaged

kernels transformed by arcsine j; prior to analysis. At the time of captures

recording, 15 out of27 wheat-on-whet fields were already approaching the

heading stage, and thus were not included in this analysis. 42

20 20 y=0.50x-0.11 Y = 0.56 x - 0.50 • 2= r2= 0.3849 r 0.385 • • p= 0.041 • 15 p= 0.047 15 Heading time 1 day after heading

• 10 10 • • ••• --.. ~ 5 5 Q) 0 2 4 6 0 2 4 6 c Cf) () 20 20 l-co ---...... y = 0.59 x - 0.75 Y= 0.60 x - 0.91 Cf) 2= • 2= • Q) r 0.377 • r 0.366 • I-> p= 0.039 p= 0.040 co 15 15 ..c 2 days after heading 3 days after heading ...... eu --.. ~ 0 • • 10 • 10 • ---Cf) Q) • • c I. • I- •• Q) ~ • 5 5 "0 Q) 0 2 4 6 0 2 4 6 0) co E co 20 20 0 2= r2= 0.281 r 0.2002 p= 0.067 • p= 0.119 • • 5 days after heading • 15 4 days after heading 15

• ,. • '- . 10 • 10 • • • • • •• • • • 5 +------,------,------,.---' 5+-----.------.------r---.J o 2 46024 6 Number of males captured [1092 (x+1)] 43

Figure 12. Relationship in 27 wheat-on-wheat fields in 2002 between mean cumulative

captures of male Sitodiplosis mosel/ana in pheromone-baited traps and the

percentage ofdamaged kernels at harvest. Captures were recorded over a

period of time starting at the heading stage of wheat plants and one, two, three,

four and five days thereafter. Captures ofmales transformed by leg, (x+ I) and

percentage ofdamaged kernels transformed by arcsine j; prior to analysis. 44

20 20 r2= 0.011 r2= 0.012 • • p= 0.570 • p= 0.559 • 15 1 day after heading 15 2 days after heading

... • •Ih • • 10 • • 10 • • :.. ~ .. • • •• • • •• • 5 •• 5 •• ..--.. • ~ • #' ~ a.> 0 •• •• 0 c •• • • (/') 0 1 2 3 4 5 6 0 1 2 3 4 5 6 o ro 20 20 r2: 0.014 r~ ---+-' 0.022 (/') p= 0.552 • • Q) • p= 0.452 • ~ 15 3 days after heading 15 4 days after heading co ..c +-' co •~. • • • • • ~10 • 10 - • 0 • ~. • ---(/') .... • a.> • •• • • • c 5 • • 5 • • .' L.- a.> #' #' .:::L. • • "tJ a.> 0 0) 0 ••• • • • • • co E 0 1 2 3 4 5 6 0 1 2 3 4 5 6 ro 20 0 20 r~ r2: 0.021 • 0.0001 • p= 0.454 • p= 0.965 • 15 5 days after heading 15 6 days after heading

• •• .. • • •• • 10 • 10 • • • • • •• • • • • • II • , • • • 5 •• 5 • #' • ••

0 •• • • 0 .. • • 0 2 3 4 5 6 0 2 3 4 5 6 Number of males captured [1092 (x+1)] - 45

Figure 13. Relationship in 22 wheat-on-nonwheat fields near Kamsack (Saskatchewan) in

2002 'between (A, B) extrapolated numbers of cocooning Sitodiplosis

2 mosellana larvae in 1 m ofsoil in the adjacent fields cultivated with wheat in

2001 and mean numbers of larvae per wheat head per field (A), or percent

damage kernels at harvest per field (B), and (C) between mean numbers of

larvae per wheat head per field and percent damaged kernels at harvest.

Spearman correlation coefficients (rs), or coefficients ofdetermination (1'2), and

probability levels (P) are given for each relationship. All data transformed by

log, (x+ 1), except for percentage ofdamaged kernels transformed by arcsine

j; prior to analysis. 46

...... co 0) N .c; ~(/)g '--UN .A 0)0) r = 0.013 0-;;:: .~ 2 s • • O)c ...... cu.- cu p= 0.952 • L~.---...... c.0) cu+ ~ • • ""X.c. °N:~ • '--O)~ • • ~Ou • • E ...... Q) ::::lu • • c cu m> • 0) .- • • c.c. == • cu ::::l • 0) U 2 0 +-....,.-----.-----r-----r-----r----,-----!• • o 2 4 6 8 10 12 Number of larvae per m2 [I092(x+1)] in adjacent fields cultivated with wheat in 2001 25 --,------,

B r =0.231 20 s • P = 0.298 • 15 • • • • ~ • • ~~ 10 '-0 • ~N '--c • • ...... cu ·- 5 • ...... cu • (/)0)O).c. • 2: ~ 0 • • •• ..ccu .c...... +--.------,----,----,------r---,----....1 m'~ o 2 4 6 8 10 12 Number of larvae per m2 [I092(x+1)] in adjacent ...... "D ~2 fields cultivated with wtieat in 2001 ...... CU s: 2; 25 --,------, 0)­ c::::l '--U c r2 0099 ~ {5 20 = "DO) P =0.164 • 0);;:: • O)C CU ._ 15 E • • cu • • o , • 10 • •• 5 • • • • o •• • • 0.0 0.5 1.0 1.5 2.0 2.5 Mean number of larvae per wheat head [I092(x+1)] in fields cultivated with wheat in 2002 47

Table 2. For wheat-on-nonwheat fields, coefficients of determination (r2) and

associated probabilities (P) between numbers ofmale Sitodiplosis mosel/ana

captured in pheromone-baited traps and percent damaged kernels at harvest, in

relation to the period during which trap captures were recorded. All data

transformed by 10g2 (x+ 1), except for percentage ofdamaged kernels

transformed by arcsine E prior to anal ysis.

Trapping period n r2 P

Onset of flight to heading stage ofwheat plants 18 0.132 0.137 Onset of flight to 1 day after heading stage of wheat plants 18 0.101 0.198 Onset of flight to 2 days after heading stage of wheat plants 18 0.075 0.273 Onset offlight to 3 days after heading stage of wheat plants 18 0.072 0.279 Onset offlight to 4 days after heading stage of wheat plants 18 0.069 0.293 Onset of flight to 5 days after heading stage ofwheat plants 18 0.064 0.313 Onset offlight to 6 days after heading stage ofwheat plants 18 0.060 0.329

5 days before heading to heading 15 0.023 0.587 5 days before heading to 1 day thereafter 15 0.011 0.708 5 days before heading to 2 days thereafter 15 0.004 0.827 5 days before heading to 3 days thereafter 15 0.005 0.795 5 days before heading to 4 days thereafter 15 0.005 0.794 5 days before beading to 5 days thereafter 15 0.005 0.805 5 days before heading to 6 days thereafter 15 0.004 0.804

Day ofbeading to 1 day thereafter 22 0.139 0.087 Day of heading to 2 days thereafter 22 0.149 0.076 Day ofheading to 3 days thereafter 22 0.155 0.070 Day ofheading to 4 days thereafter 22 0.049 0.324 Day of heading to 5 days thereafter 22 0.017 0.560 Day ofheading to 6 days thereafter 22 0.019 0.546 48

3.4 Discussion

In wheat-on-wheat fields, my data validate the method of counting larvae in wheat beads to predict the percentage ofinfested seeds (Olfert at al. 1985; Figure 9 C).

The results also demonstrate that it may be possible to use pheromone-baited traps to develop an action threshold for insecticidal control ofS. mosellana (Figures 10 and 11).

Positive correlations between cumulative captures of males in pheromone-baited traps and percent seed damaged at harvest (Figures 10 and 11), but not between numbers of soil-cocooning larvae and percent damaged kernels per field (Figure 9 B), suggest that male captures in pheromone-baited traps have even better predictive capability of

prospective crop damage than have numbers ofcocooning larvae in the soil. Nonetheless, soil sampling for cocooning larvae remains a powerful tool for early detection of increasing population densities and incipient outbreaks and rates ofparasitism.

To reveal differences in population densities, and for male captures to have

predictive capability of crop damage at harvest, traps need to be in the field ~ 5 days

before the wheat's heading stage. Deployment of traps just before, or at, the wheat's

heading stage would not allow enough time to capture males and to determine those fields

that warrant control measures for S. mosellana (Figure 12). Similar results were obtained

with tobacco budworms, Heliothis virescens (Fabricius) Tingle and Mitchell (1981).

Captures ofmale moths in pheromone-baited traps were best correlated with plant

damage when captured moths were recorded 1-2 weeks before plant damage assessment. 49

No significant correlations were obtained when captures were recorded within the same week or 3 weeks before plant damage assessment.

In wheat-on-nonwheat fields, there were no positive relationships between captures ofmales and crop damage (Table 2). The fact that there was also no positive correlation between numbers of kernel-feeding larvae per wheat head per field and percent kernel damage (Figure 13C) implies that either the method of counting numbers of larvae per kernel to estimate larval infestations in wheat heads (Olfert et al. 1985) significantly differed from my method ofcounting numbers of larvae per wheat head, or, that S. mosel/ana populations densities were too low to detect relationships. That only two of 20 wheat-on-nonwheat fields had ?.7% kernel damage [the economic threshold for common wheat (Lamb et al. 2000)] suggests that population densities were likely too low to find positive-correlations,

No.1 wheat crops have <2% damaged kernels (Agri-Facts, Alberta 2001). To produce a No 1 crop , the action threshold for insecticide application in wheat-on-wheat fields would be cumulative captures of 10 males per trap, corresponding to a logarithmically transformed value of 3.4 (Figure 10). With this threshold, all fields except for the one marked with an arrow (Figure 10), would have been correctly categorized as needing insecticide application when an application was warranted. No captures of adults in pheromone-baited traps would be supporting evidence that the crop has no damage caused by S. mosel/ana.

In wheat-on-wheat fields, captures of male S. mosel/ana in pheromone-baited traps seem to offer an alternative to captures in unbaited sticky traps (Lamb et al. 2000) to - 50

predict crop damage at harvest. The pheromone-based monitoring system is advantageous

in that it selectively attracts and captures male S. mosellana, facilitating the fanners'

interpretation of trapping results (Nielsen and Jensen 1993). However, the action

threshold I have proposed was based on one year's data, and must be substantiated or

modified in the future field studies, possibly through direct comparison with the system developed by Lamb et al. (2000). ------51

REFERENCES

Agri-Facts, Practical Information for Alberta's Agriculture Industry. Agdex 622-22. Alberta Agriculture Food and Rural Development. December 2001. Anonymous. 1993. Control of wheat midge. Farm facts. Saskatchewan Agriculture and Food Publication. Regina, Saskatchewan: Saskatchewan Agriculture and Food (Queen's Printer). Bakke, A., T. Saether, and T. Kvamme, 1983. Mass trapping ofthe spruce bark beetle, Ips typographus. Pheromone and trap technology. Medd . Nor. Inst. Skogforsk., 38: 1-35. Barker P.S. and R.I.H. McKenzie 1996. Possible sources of resistance to the wheat midge in wheat. Canadian Journal of Plant Science. 74: 689-695. Barker P.S., R.I.H. McKenzie and E. Czarnecki. 1995. Incidence ofdamage to spring wheat by the orange blossom wheat midge in Manitoba during 1993. Proceedings of the Entomological Society of Manitoba 51: 12-20. Barnes H.F. 1953. The wheat midge. New Biology 14: 82-103 . Barnes H.F. 1956. Gall midges of economic importance, Vol. 7. Gall midges of cereal crops.' Crossley Lockwood, London. Brown M.W. 1984. Saturation ofpheromone sticky traps by Platyn ota idaeusalis (Walker) (Lepidoptera: Tortricidae). Journal ofEconomic Entomology 77: 915­ 918. Campion, D.C. 1984. Survey ofpheromone use in pest control. Techniques in pheromone research. Edited by Hummel H.E. & T.A. Miller. Springer Verlag, New York: 405-437. Choi M.-Y, G. Khaskin, R. Gries, G. Gries, B.D . Roitberg, D.A. Raworth, D.-H. Kim , and R.G . Bennett . 2004 . (2R,7S)-Diacetoxytridecane: sex sheromone of the aphidophagous gall midge , Aphidoletes aphidimyza. Journal of Chemical Ecology 30: 659-670. Ding H. and R.J. Lamb. 1999. Oviposition and larval establishment ofSitodiplosis mosellana (Diptera: Cecidomyiidae) on wheat (Gramineae) at different growth stages . The Canadian Entomologist 131: 475-481. Doane J.F., 0.0. Olfert and M.K. Mukerji. 1987. Extraction precision ofsieving and brine flotation for removal of wheat midge, Sitodiplosis mosellana (Diptera: Cecidomyiidae), cocoons and larvae from soil. Journal of Economic Entomology 80: 268-271. Doane, J.F., R. DeClerck-Floate and A.P. Arthur. 1989. Description ofthe life stages of Macroglenes penetrans (Kirby) (Hymenoptera: Chalcidoidea, Pteromalidae), a 52

parasitoid of the wheat midge , Sitodiplosis moseffana (Gehin) (Diptera: Cecidomyiidae). The Canadian Entomologist 121: 1041-1048. Doane J.F., M.K. Mukerji and O. Olfert. 2000. Sampling distribution and sequential sampling for subterranean stages of orange wheat blossom midge, Sitodiplosis moseffana (Gehin) (Diptera: Cecidomyiidae) in spring wheat. Crop Protection 19: 427-434. Elkinton, lS. and R.T. Carde. 1981. The use ofpheromone traps to monitor distribution and population trends of the gypsy moth. In: Management ofInsects Pests with Semiochemicals: Concepts and Practice. Mitchell, E.R. (ed.). Plenum Press, New York . Pp. 41-56. Elliott, R.H. 1998. Evaluation of insecticides for protection of wheat against damage by the wheat midge, Sitodiplosis moseffana (Gehin) (Diptera: Cecidomyiidae). The Canadian Entomologist 120: 615-626. Elliott R.H. and L.W. Mann. 1996. Susceptibility of red spring wheat, Triticum aestivum cv. Katepwa, during heading and anthesis to damage by wheat midge, Sitodiplosis moseffana (Gehin) (Diptera: Cecidomyiidae). The Canadian Entomologist 128: 367-375. Evenden M.L. , J.H. Borden and G.A. Van Sickle. 1995. Predictive capabilities ofa pheromone-based monitoring system for western hemlock looper (Lepidoptera: Geometridae). Environmental Entomology 24: 933-943. Felt E.P. 1921. Wheat midge , Thecodiplosis moseffana (Gehin). Bulletin New York Museum 231: 35-54. Floate K.D, J.F. Doane and C. Gillott. 1990. Carabid predators of the wheat midge, Sitodiplosis moseflana (Diptera: Cecidomyiidae), Saskatchewan. Environmental Entomology 19: 1503-1511. Foster, S.P., M.O. Harris and lG. Millar. 1991. Identification ofthe sex pheromone of the Hessian fly, Mayetiola destructor (Say). Naturwissenschaften. 78: 130-131. Glogoza P. 2003. Orange wheat blossom midge , The basic. Online publication. www.ag.ndsu.nodak.edu/aginfo/entomology/entupdates/Wheat_Midge/wheat_mi dge_faqs.htm Grant G.G. 1991. Development and use ofpheromones for monitoring lepidopteran forest defoliators in North America. Forest Ecology and Management 39: 153-162. Gries R., G. Gries, G. Khaskin, S. King, O. Olfert, L.-A Kaminski, R. Lamb and R. Bennet. 2000. Sex pheromone of orange wheat blossom midge , Sitodiplosis moseffana. Naturwissenschaften 87: 450-454. Gries, R., G. Khaskin, G. Gries, R.G. Bennett, G.G.S. King, P. Morewood, K.N. Slessor, and W.DJ. Morewood. 2002. (Z,Z)-4,7-tridecadien-(S)-2-yl acetate: sex pheromone ofDouglas-fir cone gall midge, Contarinia oregonensis . Chemical Ecology 28: 2283-2297. Harris, L. 1996. Orange wheat blossom midge Sitodiplosis moseffana. Factsheet. Sustainable Agriculture Facts Growing for tomorrow. Technical information for 53

conservation farmers. Agriculture and Agri-Food Canada - Manitoba, Saskatchewan, Alberta. 6 pp . Hartley S., 1. Byers, B. Elliott, L. Kaminski, O. Olfert, and D. Giffen. 2001. Forecast of Wheat Midge in Alberta and Saskatchewan for 2002 Agriculture and Agri-Food Canada - Saskatoon Research Centre, online publication (http://res2.agr.gc.ca/saskatoon/result/wheatmidge2002- cecidomyieble2002_e.htm) Helenius J. and S. Kurppa. 1989. Quality losses in wheat caused by orange wheat blossom midge Sitodiplosis mosellana. Annals of Applied Biology. 114: 409­ 417. Hillbur, Y 2001. A chiral sex pheromone system in the pea midge, Journal of Chemical Ecology 27 : 1391-1407. Hillbur, Y, A El-Sayed, M. Bengtsson, 1. Lofqvist, A Biddle, E. Plass, and W. Francke. 2000. Laboratory and field study ofthe attraction ofmale pea midges, Contarinia pisi, to synthetic sex pheromone components. Journal of Chemical Ecology 26 :1941-1952. JMP IN Version 4.0.3 , © SAS Institute Inc. Knodel J.1. and AM. Agnello. 1990. Field comparison ofnonsticky and sticky pheromone traps for monitoring fruit pests in western New York. Journal of Economic Entomology 83: 197-204. Knodel, J.1. 1998. Results of larval wheat midge survey 1998. North Dakota State University Crop and Pest Report, August 27, 1998 . Lamb J.R. 2001. Resistance to wheat midge for Canadian wheats. Factsheet. AAFC Cereal Research Centre - Media Service. 1 pp Lamb, R.1., I.L. Wise, 0.0. Olfert, 1. Gavloski, and P.S. Barker. 1999. Distribution and seasonal abundance ofSitodiplosis mosellana (Gehin) (Diptera: Cecidomyiidae) in spring wheat. The Canadian Entomologist 131: 387-397. Lamb R.1., R.I.H. McKenzie, I.L. Wise, P.S. Barker, and M.A.H. Smith. 2000. Resistance to Sitodiplosis mosellana (Diptera: Cecidomyiidae) in spring wheat (Gramineae). The Canadian Entomologist 132: 591-605. Lamb, R.1., L.-A. Kaminski, 0.0. Olfert, I.L. Wise, and 1.E. Gavloski. 2002. Making control decisions for Sitodiplosis mosellana (Diptera: Cecidomyiidae) in wheat (Gramineae) using sticky traps. The Canadian Entomologist 134: 851-854. McBrien, H.L., GJ.R. Judd , 1.H. Borden, and R.F. Smith. 1994. Development ofsex phermomone-baited traps for monitoring Camplyomma verbasci (Heteroptera: Miridae). Physiological and Chemical Ecology 23: 442-446. Millar, r.o., K.M. Daane, S. McElfresh, lA. Moreira, R. Malakar-Kuenen, M. Guillen, and W . Bentley. 2002. Development and optimization of method for using sex pheromone for monitoring the mealybug Planococcus ficus (Homoptera: Pseudococcidae) in California Vineyards. Journal of Economic Entomology 95 : 706-716. 54

Miller, C.A. and G.A. McDougall. 1973. Spruce budwonn moth trapping using virgin females. Canadian Journal ofZoology 51: 853-858. Miller, B.S. and P. Halton. 1961. The damage to wheat kernels caused by the wheat blossom midge (Suodiplosis mosellana). Journal ofthe Science ofFood and Agriculture 12: 391-398. Mongrain, D., L. Couture, J.-P. Dubuc, and A. Comeau. 1997. Occurrence of the orange wheat blossom midge (Diptera: Cecidomyiidae) in Quebec and its incidence on wheat grain microflora. Phytoprotection 78: 17-22. Morewood, P. 1998. Development of pheromone-based monitoring and detection ofnun moth, Lymantria monacha (L.) (Lepidoptera: Lymantriidae). Master of Pest Management Thesis. Simon Fraser University Morewood P., G. Gries , J. Liska, P. Kapitola, D. Haufiler, K. Moller, and H. Bogenshultz. 2000. Towards pheromone-based monitoring of nun moth, Lymantria monacha (L.) (Lep., Lymantriidae) populations. Journal ofApplied Entomology 124: 77­ 85. Morewood P, W.O . Morewood, R.G. Bennett, G. Gries . 2002. Potential for pheromone­ baited traps to predict seed loss caused by Contarinia oregonensis (Diptera: Cecidomyiidae). The Canadian Entomologist 134: 689-697. Mukerji M.K. , 0 .0. Olfert, and J.F. Doane. 1988. Development of sampling design for eggs and larval populations of the wheat midge, Sitodiplosis mosellana (Gehin) (Diptera: Cecidomyiidae), in wheat. The Canadian Entomologist 120: 497-505. Ngollo E.D. , E. Groden, 1.F. Dill, and D. Handley. 2000. Monitoring ofthe European corn borer (Lepidoptera: Pyralidae) in central Maine. Journal ofEconomic Entomology 90: 256-263. Nielsen, B.S. and T.S. Jensen. 1993. Spring dispersal ofSitona lineatus: the use of aggregation pheromone traps for monitoring. Entomologia Experimentalis et Applicata Vol: 66: 21-30 . Oakley, IN., D.I. Green, A.E. Jones, 1.8. Kilpatrick, 1.E.B.Young. 1994. Forecasting the abundance oforange wheat blossom midge in wheat. Brighton Crop Protection Conference - pests and diseases. Oakley J.N. , P.c. Cumbleton, S.J. Corbett, P. Saunders, 0.1. Green, 1.E.B. Young, and R. Rodgers. 1998. Prediction of orange wheat blossom midge activity and risk of damage. Crop Protection 17: 145-149. Olfert 0.0., Mukerji M.K., Doane 1.F. 1985. Relationship between infestation levels and yield loss caused by wheat midge, Sitodiplosis miosellana (Gehin) (Diptera: Cecidomyiidae). The Canadian Entomologist 124: 501-507. Pivnik K.A. 1993. Response of males to female sex pheromone in orange wheat blossom midge , Sitodiplosis mosellana (Gehin) (Diptera: Cecidomyiidae). Journal of Chemical Ecology 914: 1677-1689. ------55

Pivnik K.A. and E. Labbe. 1992. Emergence and calling rhythms, and mating behaviour of the orange wheat blossom midge, Sitodiplosis mosellana (Gehin) (Diptera: Cecidomyiidae). The Canadian Entomologist 125: 725-736. Pivnik K.A. and E. Labbe. 1993. Daily patterns of activity of females of the orange wheat blossom midge, Sitodiplosis mosellana (Gehin) (Diptera: Cecidomyiidae). The Canadian Entomologist 125: 725-736. Qureshi Z.A., N. Ahmad and T. Hussain. 1993 Pheromone trap catches as a means of prediction damage by pink bollworm larvae in cotton. Crop Protection 1993 Vol. 12 no. 8: 597-600. Reeher M.M., S.G. Well so, and R.D. Freed. 1945. The wheat midge in the Pacific Northwest. Circ. USDA 732: 1-8. 1982. Positive association ofthe wheat midge (Diptera: Cecidomyiidae) with glume blotch. Journal of Economic Entomology 75: 885-887. Sanders C.J . 1978. Evaluation ofsex attractant traps for monitoring spruce budwonn populations (Lepidoptera: Tortricidae). The Canadian Entomologist 110: 43-50. Sanders, CJ. 1986. Evaluation ofhigh-capacity, nonsaturating sex pheromone traps for monitoring population densities of spruce budworm (Lepidoptera: Tortricidae). The Canadian Entomologist 118: 611-619. Sanders C.J. 1988. Monitoring spruce budworm population density with sex pheromone traps. The Canadian Entomologist 120: 175-183. Smith, M.A.H. and RJ. Lamb. 2001 . Factors influencing oviposition by Sitodiplosis mosellana (Diptera: Cecidomyiidae) on wheat spikes (Gramineae). The Canadian Entomologist 133: 533-548. Tingle, F.e. and E.R. Mitchell. 1981. Relationship between pheromone trap catches of male tobacco budwonn, larval infestation and damage levels in tobacco. Journal of Economic Entomology 74: 437--440. Wall , C. 1985. A female sex-pheromone in the pea midge, Contarinia pisi. Entomologia Experimentalis et Applicata, 39: 11-14. Wall , C. 1989. Monitoring and spray time. Insect pheromones in plant protection. Edited by A. R. Jutsum and R. F. S. Gordon. John Wiley & Sons Ltd.: 39-66. Wall, e. 1990. Principles of monitoring. Behaviour-modifying chemicals for insects management. Edited by Ridgway, R.L., R.M. Silvestein & M.N. Inscoe. Marcel Dekker Inc., New York: 9-23. Wall e. and A.R. Greenway. 1981. An effective lure for use in pheromone monitoring traps for the pea moth, Cydia nigricana (F.) Plant Pathology 30: 73-76 Weslien J. 1992. Monitoring Ips typographus (L.) populations and forecasting damage. Journal ofApplied Entomology 114: 338-340. Wright A.T. and J. Doane. 1987. Wheat midge infestation on spring cereals in Northern Saskatchewan. Canadian Journal of Plant Science 67: 117-120. 56

Zar J. H. 1999. Biostatistical anal ysis, 4th ed. Prentice Hall, Inc.,Upper Saddle River,New Jersey