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Assessment of Spider Families Clubionidae, Lycosidae & Theridiidae
as PotentialBiocontrol Agents of
Brassica Pests
Madaline HealeyMadaline Healey
Project Aim
“to determine the potential of Clubionidae, Lycosidae and Theridiidae to control
Plutella xylostella,
Crocidolomia pavonana &
Myzus persicae
in Brassica vegetable crops….”
Brassica Vegetable Pests
• Diamondback moth Plutella xylostella
• Cabbage Cluster Caterpillar
Crocidolomia pavonana
• Green Peach Aphid Myzus persicae
Brassica Vegetable Pests
• Diamondback Moth P. xylostella
• Cabbage Cluster Caterpillar
C. pavonana
• Green Peach Aphid
M. persicae
Diamondback larvae damage
Brassica Vegetable Pests
• Diamondback Moth
P. xylostella
• Cabbage Cluster Caterpillar
C. pavonana
• Green Peach Aphid
M. persicae
Cabbage cluster larvae damage
Brassica Vegetable Pests
• Diamondback moth
Plutella xylostella
• Cabbage cluster caterpillar
Crocidolomia pavonana
• Green Peach Aphid
M. persicae
Green peach nymph damage
Background
• Chemical resistance
• South East QLD Lockyer Valley survey
– 70% utilise IPM– 30% consciously protect
natural enemies
• Spider dominant natural enemy in Brassica vegetables
Spiders in Brassica Vegetables
Clubionidae
-hunting plant dweller
Lycosidae
-hunting ground dweller
Theridiidae
-tangle web-weaver
Spiders in Brassica Vegetables
Clubionidae -hunting plant dweller
Lycosidae
-hunting ground dweller
Theridiidae
-tangle web-weaver
Spiders in Brassica Vegetables
Clubionidae
-hunting plant dweller
Lycosidae -hunting ground dweller
Theridiidae
-tangle web-weaver
Spiders in Brassica Vegetables
Clubionidae
-hunting plant dweller
Lycosidae
-hunting ground dweller
Theridiidae -tangle web-weaver
Spiders in Brassica Vegetables
What impact will these spiders have in reducing pests?
Objectives
• determine the ability of three spider families to reduce pest populations
• determine if a connection exists between spider and prey preference
• determine spider predation potential as a naturally occurring biocontrol agent in Brassica vegetables
Laboratory ExperimentsExp 1
No choice Lepidoptera predation
Diamondback & Cabbage cluster Five larvae per trtSix trts, 2 controlsConsumption after 24 hours
Exp 2
Lepidoptera prey preference
Diamondback & Cabbage clusterOne larva of each preyThree trts, one controlFirst prey attacked
Exp 3 Lepidoptera prey
preferenceby Lycosidae
Diamondback & Cabbage clusterOne larva each preyOne trt, one controlFirst prey attacked
Exp 4
Prey species preference
Cabbage cluster & AphidOne larva each preyThree trts, one controlFirst prey attacked
Experimental Collection
• Colonies– Diamondback moth– Green peach aphid
• Organic broccoli plantings– Spiders– Cabbage cluster egg
raftsCabbage cluster egg raft
Experimental Arena
Caged arena with broccoli seedling
Experiment One Lepidoptera predation
• Two-factor ANOVA
• No significant difference between prey mortality
P = 0.715
• No interaction P = 0.195
• Spider families will readily predate both prey
• No significant difference between treatments
LSD = 1.361
Mean live larvae after 24 hours
0
0.5
1
1.5
2
2.5
3
3.5
4
Clb&DBM(Trt1)
Clb&Croc(Trt2)
Lyc&DBM(Trt3)
Lyc&Croc(Trt4)
Thr&DBM(Trt5)
Thr&Croc(Trt6)
Experiment Two Lepidoptera prey preference
• Chi-square analysis• Significant prey
preference– Clear choice of prey
dependant on spider type
χ² = 0.010
DBM – Diamondback moth
CCC – Cabbage cluster
87.5
12.5
25
75
17
83
0 00
10
20
30
40
50
60
70
80
90
Clubionidae Lycosidae Theridiidae Control
Total % of larvae consumed first
DBM
CCC
Experiment Three Lycosidae prey preference
• Chi-square analysis
• No significant prey preference– Prey choice independent of
spider type
χ² = 0.157
33.5
66.5
0
10
20
30
40
50
60
70
Diamondbackmoth
Cabbage clustercaterpillar
Total % of larvae consumed first
Experiment Four Prey species preference
• Chi-square analysis• No significant prey
preference– Prey choice independent of
spider type
χ² = 0.117
CCC – Cabbage cluster
GPA – Green peach aphid
37.542.5
33.5
66.5
77.5
12.5
0
10
20
30
40
50
60
70
80
Clubionidae Lycosidae Theridiidae
Total % of prey consumed first
CCC
GPA
General Discussion• All spider treatments will consume three
Brassica pests– Generalist predator more effective than
selective
• Prey preference– Physical and behavioural characteristics
• Diamondback larvae active• Cabbage cluster larvae sluggish• Green peach aphid nymphs passive
Future Research
• Repeat experiments – increase experimental
units
• Lycosidae on plant
Future Research
• Cage exclusion
trials
• Spider thresholds– No. spider per metre²
Semi-excluded cage
Summary• Clubionidae, Lycosidae & Theridiidae will
predate
Plutella xylostella
Crocidolomia pavonana
Myzus persicae
• Potential naturally occurring biological control agent
Acknowledgements
Dr. Graham Brodie
University of Melbourne
Dr. Lara Senior
Agri-Science Queensland
Ms. M. Firell
Agri-Science Queensland