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