Crop protection assessment of thrips species complex and economic loss in macadamia orchards in...

Towards Understanding the Economic Impact

of Thrips in South Africa: Preliminary Findings

Colleen Hepburn¹, Michael Stiller² & Martin Villet¹ ¹Department of Zoology & Entomology, Rhodes University, Grahamstown, South Africa

²Agricultural Research Council - Plant Protection Research Institute, National Collection of

Insects: Biosystematics, Roodeplaat, Pretoria, South Africa 1

Aims and objectives:

• Thrips complex - identify and

assign to guilds (damaging /

predatory / beneficial).

• Phenology of thrips causing

damage.

• Develop practical monitoring

and scouting strategies.

• Ascertain damage to flush,

blossoms, nut-set, small &

mature nuts.

• Determine % premature nut

drop and abscission

attributed to thrips.

2

Aims and objectives:

• Does thrips damage affect pre- and

post-zygotic development of nut?

• Does cosmetic damage (bronzing)

affect photosynthesis and / or

kernel characteristics (size / weight

/ oil content)?

• Are some cultivars more

susceptible to thrips damage?

• Begin working on IPM programme

which is ecologically sound.

• Determine % economic loss of

yield.

• Thrips complex distribution in macadamia-growing areas. Photos: Michael Stiller, ARC-PPRI (2012)

3

Order: Thrips (Thysanoptera)

• 2 suborders – Terebrantia and Tubulifera

• 9 families

• 750 genera

• 8000 extant species (> 5500 described)

50% - feed on fungi

40% - feed on dicotyledonous plants

(i.e. grasses)

9% - predatory or feed on mosses,

gymnosperms or cycads

1% - identified as serious pests

(+ transmission of viruses)

4

Average Thrips Life Cycle

(2½ - 4 days)

(1 - 2 days)

(1 - 3 days)

(Longevity

30 - 45 days

150 - 300

eggs)

(1 - 2 days)

(2 - 4 days)

(Immature stages = max.

15 days)

5

Field work (over 33 weeks) - sampling

protocol

• 13 cultivar sites

• 5 data trees in each

cultivar site (n = 65)

• 20 racemes / growth

points on each tree

sampled weekly

(n = 1300)

In total n = 42900

6

Study sites (13) and variety of cultivars

LOCALITY CULTIVAR AGE TREATED

ARC-ITSC Nelmak D Orchard Nelmak D 8 yrs No

ARC-ITSC Variety Orchard Beaumont 13 Yrs No

ARC-ITSC Variety Orchard Nelmak 2 13 Yrs No

ARC-ITSC Variety Orchard 788 13 Yrs No

ARC-ITSC Variety Orchard A4 13 Yrs No

ARC-ITSC Variety Orchard 816 13 Yrs No

ARC-ITSC Variety Orchard A16 13 Yrs No

ARC Friedenheim Farm Beaumont 6 yrs Yes

Commercial Farm 788 4 yrs Yes

Commercial Farm Nelmak D 6 yrs Yes

Commercial Farm 816 4 yrs Yes

Commercial Farm Beaumont 12 yrs Yes

Commercial Farm Nelmak D 12 yrs Yes 7

20 growth points per tree (i.e. new

flush, blossoms, nut set, small

nuts, mature nuts) sampled weekly

8

Photos representing raceme developmental stages

and abscised nuts for each site were taken weekly

(phenology)

9

During the last 7 weeks of sampling, abscised nuts

with and without thrips damage + 20 random nut

sample from trees were tested for maturity (i.e.

dehusked, dried, cracked & floated)

10

AVERAGE # OF THRIPS COLLECTED FROM DATA TREES AT

ALL 13 SITES OVER THE 33 WEEK PERIOD

0

5

10

15

20

25

30

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

ARC NELMAK D 8YRS

ARC VARIETY ORCHARD BEAUMONT 13YRS

ARC VARIETY ORCHARD NELMAK 2 13YRS

ARC VARIETY ORCHARD 788 13YRS

ARC VARIETY ORCHARD A4 13YRS

ARC VARIETY ORCHARD 816 13YRS

ARC VARIETY ORCHARD A16 13YRS

ARC FRIEDENHEIM BEAUMONT 6YRS

COMMERCIAL FARM 788 4YRS

COMMERCIAL FARM NELMAK D 6YRS

COMMERCIAL FARM 816 4YRS

COMMERCIAL FARM BEAUMONT 12YRS

COMMERCIAL FARM NELMAK D 12YRS

AVERAGE TEMPERATURE (°C)

AV

ER

AG

E #

TH

RIP

S F

RO

M A

LL

SIT

ES

W

EE

KL

Y A

VE

RA

GE

TE

MP

ER

AT

UR

E °C

11 WEEKS

COMMERCIAL FARM SPRAY DATES: BEAUMONT

(12 yrs) & NELMAK D (12 yrs) SITES [N.B. Sprays based on

weekly scouting records]

0

5

10

15

20

25

30

0

50

100

150

200

250

300

COMMERCIAL FARM BEAUMONT 12YRS

COMMERCIAL FARM NELMAK D 12YRS

AVERAGE TEMPERATURE (°C)

AV

ER

AG

E #

TH

RIP

S

Acephate

Cypermethrin

Cypermethrin

Cypermethrin

Cypermethrin

WE

EK

LY

AV

ER

AG

E T

EM

PE

RA

TU

RE

°C

WEEKS 12

Defining thrips damage:

Only green, shiny nuts on

tree and green abscised

nuts as at 11 November

2011

13

Two weeks later (26 November 2011), there

was a change in colour of some of the nuts

14

Abscised nuts: different types of husk damage

15

TOTAL # ABSCISED NUTS OVER 33 WEEK

SAMPLING PERIOD

16

0

5

10

15

20

25

30

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

2800

3000

3200

3400

3600

3800

4000

4200

ARC NEL D 8YRS

ARC VAR ORCH B'MONT 13YRS

ARC VAR ORCH NEL 2 13YRS

ARC VAR ORCH 788 13YRS

ARC VAR ORCH A4 13YRS

ARC VAR ORCH 816 13YRS

ARC VAR ORCH A16 13YRS

ARC F'HEIM B'MONT 6YRS

COMM FARM 788 4YRS

COMM FARM NEL D 6YRS

COMM FARM 816 4YRS

COMM FARM B'MONT 12YRS

COMM FARM NEL D 12YRS

AVERAGE TEMPERATURE (°C)

TO

TA

L #

AB

SC

ISE

D N

UT

S

WE

EK

LY

AV

ER

AG

E T

EM

PE

RA

TU

RE

WEEKS

AVERAGE NUMBER OF ABSCISED NUTS SHOWN BY

STUDY SITE IN DESCENDING ORDER

17

RATING

STUDY SITE

AVERAGE #

ABSCISED

NUTS

1. Commercial Farm Beaumont 12 Yrs 391

2. Commercial Farm Nelmak D 12 Yrs 222

3. Commercial Farm 816 4 Yrs 170

4. ARC Variety Orchard Nelmak 2 13 Yrs 139

5. ARC Variety Orchard A16 13 Yrs 135

6. ARC Variety Orchard A4 13 Yrs 94

7. ARC Variety Orchard 816 13 Yrs 93

8. ARC Nelmak D Orchard 8 Yrs 62

9. ARC Variety Orchard 788 13 Yrs 61

10. Commercial Farm Nelmak D 6 Yrs 54

11. ARC Variety Orchard Beaumont 13 Yrs 53

12. Commercial Farm 788 4 Yrs 44

13. ARC Friedenheim Farm Beaumont 6 Yrs 25

TOTAL # ABSCISED NUTS WITH THRIPS DAMAGE

OVER TIME.

18

0

5

10

15

20

25

30

0

200

400

600

800

1000

1200

ARC NEL D 6YRS

ARC VAR ORCH B'MONT 13YRS

ARC VAR ORCH NEL 2 13YRS

ARC VAR ORCH 788 13YRS

ARC VAR ORCH A4 13YRS

ARC VAR ORCH 816 13YRS

ARC VAR ORCH A16 13YRS

ARC F'HEIM B'MONT 6YRS

COMM FARM 788 4YRS

COMM FARM NEL D 6YRS

COMM FARM 816 4YRS

COMM FARM B'MONT 12YRS

COMM FARM NEL D 12YRS

WEEKLY AVERAGE TEMPERATURE (°C)

TO

TA

L #

NU

TS

WIT

H T

HR

IPS

DA

MA

GE

WEEKS

WE

EK

LY

AV

ER

AG

E T

EM

PE

RA

TU

RE

°C

AVERAGE # ABSCISED NUTS WITH AND WITHOUT

THRIPS DAMAGE – ALL SITES

19

0

5

10

15

20

25

30

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

AVE # ABSCISED NUTS

AVE # ABSCISED NUTS NO THRIPS DAMAGE

AVE # ABSCISED NUTS WITH THRIPS DAMAGE

AVERAGE TEMPERATURE (°C)

AV

ER

AG

E #

AB

SC

ISE

D N

UT

S

WE

EK

LY

AV

ER

AG

E T

EM

PE

RA

TU

RE

°C

WEEKS

0

20

40

60

80

100

120

140

160

180

200

# NUTS ABSCISED

# NUTS (No thrips dam)

# MATURE (No thrips dam)

WEEKS

0

20

40

60

80

100

120

140

160

180

200

# NUTS ABSCISED

# NUTS (Thrips dam)

# MATURE (Thrips dam)

ARC NELMAK D: MATURITY COMPARISON OF

ABSCISED NUTS WITH AND WITHOUT THRIPS DAMAGE

20 WEEKS

ARC VARIETY ORCHARD 816: MATURITY COMPARISON OF

ABSCISED NUTS WITH AND WITHOUT THRIPS DAMAGE

0

10

20

30

40

50

60

70

80

90

# NUTS ABSCISED

# NUTS (No thrips dam)

# MATURE (No thrips dam)

# N

UT

S

WEEKS

0

10

20

30

40

50

60

70

80

90

# NUTS ABSCISED

# NUTS (Thrips dam)

# MATURE (Thrips dam)

# N

UT

S

WEEKS 21

ARC VARIETY ORCHARD A16: MATURITY COMPARISON OF

ABSCISED NUTS WITH AND WITHOUT THRIPS DAMAGE

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

# NUTS ABSCISED

# NUTS (No thrips dam)

# MATURE (No thrips dam)

# N

UT

S

WEEKS

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

# NUTS ABSCISED

# NUTS (Thrips dam)

# MATURE (Thrips dam)

# N

UT

S

WEEKS 22

a b c

ARC NELMAK D: Photos of damage to nuts with thrips

damage, without thrips damage and 20 nut sample

tested for oil content and maturity (N.B. Stinkbug damage)

23

Identification

During the 2011-2012 season a

total of 44 062 specimens

collected and counted

A number of morphological

characters are used to identify to

species (i.e. setae, surface

sculpture, detail on antennae,

wing venation and setation)

Adults 1.0 – 1.6 mm long

24

Some of the thrips species being identified by Michael Stiller, ARC-PPRI National Collection of Insects: Biosystematics, Pretoria, South Africa

So far no S. aurantii (citrus) or Heliothrips haemorrhoidalis (greenhouse)

Thrips gowdeyi (Bagnall)

Thrips tenellus Trybom

Thrips pusillus Bagnall

Taeniothrips sp.

Scirtothrips ?combreti Fauré

Megalurothrips sjostedti Trybom

Hercinothrips sp.

Helionothrips sp.

25

Identification/Photos: Michael Stiller, ARC-PPRI Biosystematics, Pretoria, SA

26

Species of mites identified by Eddie Ueckermann, ARC-PPRI National Collection of Insects: Biosystematics, Pretoria, South Africa

Agistemus africanus (Stigmaeidae) Red Velvet Mite Photo: Edublogs.org

Anystis baccarum (Anystidae) Whirligig mite Photo: BugGuide.net

Hexibdella sp. (Bdellidae)

Snout Mite

Photo: Tom Murray

ALL PREDATORY MITES

Phytoseiidae Amblyseius herbicolus

Typhlodromus (Anthoseius) vescus

Typhlodromus (Anthoseius) celastrus

Neoseiulus barkeri

Bdellidae Hexibdella sp. near singula

Anystidae Anystis baccarum

Stigmaeidae Agistemus africanus

Tetranychidae Eutetranychus sp.

Mononychellus nr, heteromniae

So far no broad mite or citrus mites 27

Aims & Objectives: 2012-2013 Season

13 July 2012: Set up study sites and

began scouting and monitoring.

Continuing with identification of thrips

species and sorting into guilds,

incorporated temperature and rainfall in

data, working out phenology of

macadamia cultivars from photo data.

Aug: Soil application of Metarhizium

(entomopathogenic fungi) at some of

the sites.

Field collections: thrips complex

distribution of thrips in macadamia

growing areas of South Africa. Photo Source: Wikipedia.org

Metarhizium on cockroach 28

Acknowledgements:

SAMAC (Research Project Funding 2011-2012, 2012-2013)

Rhodes University, Grahamstown, South Africa (Scholarship 2011)

National Research Foundation, Pretoria, South Africa (Scholarship 2012-2014)

Ernst & Ethel Eriksen Trust, Bryanston, South Africa (Scholarship 2011 & 2012)

Mr Johannes Ngomane, Dr Schalk Schoeman, Prof Randall

Hepburn, Dr Eddie Ueckermann, Messrs Gerhard Nortjé,

Andrew Sheard, Alwyn du Preez and Len Hobson

Subtrop, Tzaneen, and ARC-ITSC, Nelspruit, South Africa

ERNST AND ETHEL ERIKSEN TRUST

29