Effect of Lygus lineolaris on navy beans in Manitoba

Transcription

1 Effect of Lygus lineolaris on navy beans in Manitoba T. Nagalingam and N. J. Holliday Department of Entomology University of Manitoba, Canada R3T 2N2

2 Objectives To examine the effect of different stages of plant bugs on different growth stages of navy beans

3 Plant bugs on navy beans in Manitoba Lygus lineolaris 87% Lygus borealis 2% Lygus elisus 2% Adelphocoris lineolatus 4%

4 Different spatial scales Whole plot Field cage Whole plant Single inflorescence

5 Plant and insect stages R2-R3 Stage R4-R5 Stage R6-R7 Stage R6-R7 Maturity Adults 5 th instar Nymphs

6 Crop stage R2-R3 R4-R5 R6-R7 Inflorescence X X X Whole plant X X? X Field cage 2009, , , 2011

7 Field cage studies

8 Field cage studies R2-R3 Stage R4-R5 Stage R6-R7 Stage R4-R5 Stage R6-R7 Stage R6-R7 Stage Harvest

9 Laboratory experiments Whole plant Single inflorescence

10 Processing of samples Yield quantity Assessed in the laboratory Seed weight and seed number Marketable seed weight Quality of seeds Field cage samples: Commercial grading Laboratory experiments: Graded in the lab

11 R2-R3 stage experiments

12 R2-R3:Field cage study year 2009 Treatment Marketable seed yield (g/m 2 ) Control adults adults Significance F= 5.2, d.f= 2, 10, p < 0.05

13 R2-R3 : Field cage study year 2011 Treatment Marketable seed yield (g/m 2 ) Control adults adults Significance F= 10.7, d.f = 2, 28 p < 0.05

14 R2-R3: Inflorescence level 4 7 Marketable seed weight (g) Treatment p = Total number of abortions Treatment p = Adult 1 Nymph Control 0 1 Adult 1 Nymph Control

15 R2-R3: Whole plant level Treatment p=0.394 Treatment p=0.094 Seed weight (g) Total number of pods Adults 30 Adults Control 30 Nymphs Adults 30 Adults Control 30 Nymphs

16 Summary R2-R3 stage Cage study results Crop compensation Death of Lygus bugs Average Temperature ( C) Winnipeg, Manitoba, Canada Month June July August September Source: Environment Canada

17 R4-R5 stage experiments

18 R4-R5 field cage study: year 2011 Treatment Marketable seed yield (g/m 2 ) Control Lygus adults Lygus adults Lygus nymphs Lygus adults Lygus nymphs Lygus adults Significance F= 3.4, d.f = 6, 23 p < 0.05

19 Average effect for the presence of adults or nymphs Stage Marketable seed weight Average yield loss (Mean SE) Adult g Control Nymph g

20 Number of shriveled seeds 500 Number of shriveled seeds Treatment p= Lygus 120 Lygus Nymph 30 Lygus 60 Lygus 60 Lygus Nymph 90 Lygus Control

21 R4-R5 stage inflorescence level 5 30 Treatment p=0.003 Treatment p=0.025 Marketable seed weight (g) Number of shriveled seeds Control 3 Nymphs 3 Adults 0 Control 3 Nymphs 3 Adults

22 Laboratory: SummaryR4-R5 stage Seed shriveling is the major effect and lead to seed weight loss Nymphs are more injurious than adults Field: Preliminary results are perplexing

23 R6-R7 Experiments

24 R6-R7 field cage study: year 2010 Treatment Marketable seed weight (g/m 2 ) Control (no insects) Lygus adults Lygus nymphs Lygus adults Significance F= 0.699, d.f= 3,12, p > 0.05 Insect damage/250 ml cup of sub sample Adults Treatment p= Adults 60 Nymphs Treatments Control

25 R6-R7 field cage study: year 2011 Treatment Marketable seed weight (g/m 2 ) Control (no insects) Lygus adults Lygus nymphs Lygus adults Lygus adults Significance F= 0.380, d.f= 4,18, p > 0.05 Insect damage per 250 ml of sub sample Adults Treatment p= Adults 60 Adults 60 Nymphs Control

26 R6-R7 stage inflorescence level 4 40 Marketable seed weight (g) Treatment p= Total number of pits Treatment p= Adults 5 Nymph Control 0 5 Adults 5 Nymph Control

27 R6-R7 stage whole plant level Marketable seed weight (g) Treatment p = Treatment p = Total number of pits Adults 15 Nymphs 30 Adults 30 Nymphs Control 0 15 Adults 15 Nymphs 30 Adults 30 Nymphs Control

28 Summary R6-R7 stage No quality or quantity loss in the field cages Quality loss occurred in the laboratory due to pitting Concern about commercial grading

29 General Discussion Effect vary with crop growth stage Nymphs more injurious than adults R2 -R3 R4-R5 R6-R7

30 Acknowledgements Funding: Manitoba Pulse Growers Association Agri-Food Research and Development Institute University of Manitoba Bruce Brolley Edible bean Growers Soybean growers Advisory committee : Dr. Robert Lamb Dr. Robert Currie Dr. Susan Arntfield Dr. Rob Gulden Lisa Babey Dave Holder Leanne Peixoto Roberto Duarte Justin Crowe Jenny Mcleod Taryn Dickson Terry Sharanowski Sebastian Ibarra Sharon Surowiec Jonathan Veilleux Ben Rogala Alicia Leroux Akriti Sharma

31 THANK YOU