The role of canopy density and ground-cover vegetation on pest

and beneficial insects

Prepared by: Alana Danne

October 2014

Background

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Canopy management

closed (traditional) vs. open (encouraged)

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Fruitspotting bug damage

Premature nut drop (Sep/Oct-Dec)

Entry point for disease

Overall reduction in yield

Methods

Study sites

Two organic

macadamia orchards

in northern NSW

Common varieties,

similar tree age,

similar tree spacing,

similar ground cover

vegetation

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Both with land aspect that produced

‘light’ and ‘dark’ blocks

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Invertebrates were sampled once a month in ‘light’ and ‘dark’ blocks over summer 2011/2012 at two sites

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• Nut production assessed from 72 trees in ‘light’ and ‘dark’ blocks at two sites

Fallen nut counted each month from Nov 2012 -June 2013

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Sampled fallen nut for fruitspotting bug damage from 72 trees in ‘light’ and ‘dark’ blocks each

month from Nov 2012 - Jun 2013

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Levels of predation in ‘light’ and ‘dark’ blocks assessed: sentinel fruitspotting bug eggs

attached to leaves.

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Questions?

How do closed canopy orchards with no ground-cover vegetation vs. open canopy orchards with flowering ground-cover vegetation affect:

1. Abundances of pest and beneficial invertebrates?

2. Nut production?

3. Levels of fruitspotting bug damage?

4. Predation of sentinel fruitspotting bug eggs?

Results

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0"

20"

40"

60"

80"

100"

120"

140"

160"

total"beneficials"

parasitoids" spiders" ants"

0"

1"

2"

3"

4"

5"

6"

total"pests" other"lepidoptera"

lace"bugs" leafminers"

0"

5"

10"

15"

20"

25"

30"

total"beneficials"

parasitoids" spiders" brown"lacewings"

0"

5"

10"

15"

20"

25"

30"

total"pests" lace"bugs" leafminers"

Meannumbercollectedpersite(±SE)

mid-rowcanopy

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Nut yieldDark

Light

Nov - Feb

48%

52%

Mar - Jun

32%

68%

Nov – Jun

41%

59%

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Fruitspotting bug nut damage

0"

0.1"

0.2"

0.3"

0.4"

0.5"

0.6"

Dark" Light"

0"

0.1"

0.2"

0.3"

0.4"

0.5"

0.6"

Dark" Light"

Nov-Feb Mar-Jun

Meanproporonofnut

damagewhendamageis

presentonatree(±SE)

ab

ab

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Predation of fruitspotting bug eggs

Meanproporonofeggs

predatedupon(±SE)

0"

0.02"

0.04"

0.06"

0.08"

0.1"

0.12"

0.14"

0.16"

Dark" Light"

aa

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Conclusions

Open canopy orchards with flowering mid-row ground-cover:

• harbour a higher abundance of beneficial invertebrates, and a lower number of pest invertebrates, than ‘dark’ orchards

• increased nut production

• had lower levels of fruitspotting bug damage

• did not results in higher levels of fruitspotting bug egg predation (variable)

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Acknowledgements

Supervisors:Mike Furlong, Margie Mayfield, Nancy Schellhorn, Ruth Huwer

Funding:Australian Macadamia Society, Avocados Australia, Horticulture Australia Ltd.

Farmers at both field sites

Volunteers who helped with field work and invertebrate identification