Why trap plants could be useful against sharpshooters?

• Polyphagous vectors• Crops affected are

(usually) not preferred hosts

• Immigrate from surrounding habitats

• Thus, a trap-plant barrier could intercept incoming vectors before reaching the crop

Colonization of vineyards in California North Coast by BGSS

Show position trap plant barrier in theInterface of citrus orchard

Riparian woodSource of vectors

(from Purcell)

FUNDECITRUS

Oncometopia facialis

Dilobopterus costalimai

Bucephalogonia xanthophisAcrogonia citrina

Homalodisca ignorata

Acrogonia virescens

Parathona gratiosa

Plesiommata corniculata

Macugonalia leucomelas Sonesimia grossa

Ferrariana trivittata

Several sharpshooter vectors in citrus

Young citrus grove Primary and secondary spread

Older infected grove (inoculum source)Infected

treeHealthy

tree

Healthy nursery treesHealthy nursery trees

VectorVector controlcontrol

PruningPruning RoguingRoguing

CVC management

Problems with vector control in citrus

• High cost of insecticides• Environmental impact• Perennial crop• Multiple vector species• External sources of vectors

Young grove Neighboring

grove

Swamp or Riparian Wood

Immigration of sharpshooters to Immigration of sharpshooters to the citrus grovethe citrus grove

Trap crop

Young grove

Neighboring grove

Riparian wood or swamp

Trap crop

Inseticide treatment

Establishment of trap crop Establishment of trap crop

What characteristics are desirable in trap plants?

• Must be more attractive than crop plant

• Good feeding host

• Easy to propagate, fast growth

• Abundance of young shoots

• Must accept frequent pruning and systemic inseticides

• If possible, not a host of X. fastidiosa

Why search for nonhosts of X. fastidiosa?

• Safe trap plants – not a source of inoculum

• Rearing healthy sharpshooters (other studies)

1.1. Visual observations in several habitatsVisual observations in several habitats

2.2. Choice tests (in relation to citrus)Choice tests (in relation to citrus)

Search for attractive host plants to Search for attractive host plants to sharpshooters in S.Paulo State, Brazilsharpshooters in S.Paulo State, Brazil

Studies

Observations of sharpshooters in natural habitats Northern São Paulo State (Giustolim et al.)

SwampSwamp

Riparian woodsRiparian woods

““Cerrado”Cerrado”

Acrogonia citrina

Bucephalogonia xanthophis

Dilobopterus costalimai

Oncometopia facialis

13

17

15

21

10

8

12

13

Sharpshooter No. familiesNº speciesHost plant

Total 40 20 * No. habitats surveyed: 6** No. plant species surveyed: 107 (Giustolin et al.)

Families of host plantsMain vector species Bucephalogonia xanthophis

Sharpshooters nymphs

Aloysia virgata – Aloysia virgata – visited by various sharpshootersvisited by various sharpshooters

Acrogonia Acrogonia sp.sp.

D. D. costalimaicostalimai

O. facialisO. facialis

Pseudometopia Pseudometopia sp. sp.

M. M. leucomelasleucomelas

Croton floribundus – Croton floribundus – visited by various sharpshootersvisited by various sharpshooters

O. facialisO. facialis

Pseudometopia Pseudometopia sp. sp.

Acrogonia Acrogonia sp.sp.

Homolodisca Homolodisca sp.sp.MacugonaliaMacugonalia leucomelasleucomelas

Vernonia sp1. Vernonia sp2.Pterocaulon lanatum Baccharis sp.

Asteraceae Most visited by Bucephalogonia xanthophis

Verbenaceae – Lantana camaraOncometopia facialis

Oncometopia facialis

Observations of sharpshooters in urban areas

‘boldo’Vernonia condensata

Hibiscus rosa-sinensis

Datura repens

Choice test in the greenhouse (cages)citrus X other hosts

Choice test in the greenhouse (cages)citrus X other hosts

How attractive are the host plants??

Choice study under field conditions

citrus X other hosts

Choice study under field conditions

citrus X other hosts

Piracicaba, SP, Brazil(June/04 - Feb/08)

Host species planted in areaadjacent to riparian wood

Mean number of sharpshooters observed on various host plants in area adjacent to a riparian wood. Piracicaba, SP, Brazil

Turati et al.

No. ofsharpshooters

Vernonia condensata

Citrus

Lara

nja

Pau

d´a

lho

Lant

ana

Pin

go d

e ou

ro

Lixe

ira

Cro

ton

Bol

do

Hib

isco

Bucephalogonia xanthophisParatona gratiosa

Macugonalia leucomelasCatagonalia conjunctula

Scopogonalia subolivaceaSibovia sagata

Macugonalia cavifronsAcrogonia citrina

Dilobopterus costalimai

0

0.5

1

1.5

2

2.5

3

Host plants

Sharpshooterspecies

Aloysiavirgata

Daturarepens

Lantanacamara Hibiscus

Mean number of Oncometopia facialis observed on various host plants in area adjacent to a riparian wood. Piracicaba, SP, Brazil.

Turati et al.

No. ofsharpshooters

Seasons

Host plants

Inve

rno0

4

Ver

ão 0

4/05

Out

ono

05

Ver

ão 0

5/06

Inve

rno

06

Prim

ave

ra 0

6

Ver

ão 0

6/07

Out

ono

07

Prim

ave

ra 0

7

Ver

ão 0

7/08

LaranjaPau d´alho

LixeiraHibisco

Croton Boldo

Lantana

0

5

10

15

20

25

30

35

40Lantana camara

Aloysia virgata

Vernonia condensataCrotonfloribundus

Citrus sinensis

Oncometopia facialis

Most attractive host species to the sharpshooter complex

• Vernonia condensata (‘boldo’)

• Lantana camara

• Aloysia virgata

• Croton floribundus

• Datura repens

Are there X. fastidiosa hosts among preferred hosts of citrus sharpshooters ?

Symptoms

Mechanical inoculation of X. fastidiosa

Culture-4 monthsHost plant

Aloysia virgataBaccharis sp.Cedrela odorataCroton floribundusGallesia integrifoliaGochnatia polymorphaIlex teezansLantana camaraLuehea paniculataPterocaulon lanatumStyrax ferrugineusVernonia sp1.Vernonia sp2.

ND ND

ND NDND ND

ND

0/20

0/20 0/20

0/20

0/200/20

0/20

0/14 1/14 +

0/7 2/7 +

0/20 4/20 +

0/18 0/18

0/20 0/20

0/20ND

Mechanical inoculation of Mechanical inoculation of V. condensataV. condensata with with X. X. fastidiosafastidiosa

Positive plants by culture and PCR(months after inoculation) Plant

1 6 12

Vernonia condensataVernonia condensata

Aloysia virgataAloysia virgata

Citrus sinensisCitrus sinensis

0/20 0/20 0/200/20 0/20 0/20

0/5 0/50/5 0/5 0/5 0/5

2/10 4/10 7/102/10 4/10 7/10

(Marucci et al. 2003)

Plant 7 14

Vernonia Vernonia

condensatacondensata

Citrus sinensisCitrus sinensis

0/15 0/150/15 0/15

3/10 1/103/10 1/10

Positive plants by culture/PCR (days after inoculation)

Mechanical inoculation of Mechanical inoculation of V. condensataV. condensata with with X. fastidiosaX. fastidiosa

(Marucci et al. 2003)

Rearing healthy vectorsRearing healthy vectors- Vernonia condensata - - Vernonia condensata -

RodrigoAlmeida (1999)

0102030405060708090

Vernoniacondensata

V. condensata andCitrus

Citrus

Nym

ph

al V

iab

ility

(%

)

Oncometopia facialis Dilobopterus costalimais

Vernonia condensata as a developmental host for sharpshooters

Milanez et al. (2001)

Testing trap plants

in a citrus grove

Oxford FarmGavião Peixoto, SP

(Oct/2004)

Testing trap plants

in a citrus grove

Oxford FarmGavião Peixoto, SP

(Oct/2004)

Source of vectorsSwampy wood

Citrus grove

Trap plant barrier

Trap-plant barrier

• block with 225 plants (5 rows of 50 m)

Aloysia virgata*

Croton floribundus*

Croton urucurana

Galesia integrifolia

Guazuma unifolia

Senna alata

Tapirira guianensis

Duranta repens*

Eupatorium sp.

Lantana camara*

Mimosa caesalpinaefolina

Vernonia condensata*

Vernonia polyantes

Trees (8 species) Shrubs (6 species)

Establishing the trap-plant barrier

10/19/04 (planting date)

12/27/04 (2 months later)

Plant height (3 months after planting)

1,0 m

0

50

100

150

200

250

C. flo

ribundus

C. uru

cura

na

G. inte

grifolia

A. virg

ata

T. guia

nensi

s

S. ala

ta

G. unifo

lia

M. c

aesa

lpin

eafo

lia

B. dra

cuncu

lifolia

L. cam

ara

V. poly

anth

es

V. conden

sata

E. lae

vigat

um

D. rep

ens

Alt

ura

Fin

al (

cm)

Plantheight(cm)

Dec/05 (14 months after planting)

Establishing the trap-plant barrier

Treatment with imidacloprid

Evaluation of sharpshooter population in plots with or without trap-plant barrier by yelllow stick cards

Trap plant barrier

Swamp

No barrier

Vector movement to the citrus grove

50 m

b

a

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

Subtalhão A Subtalhão B

nº

de

inse

tos

cap

tura

dos

Incidence of sharpshooters in plots with (A) or without (B) the trap-plant barrier

Overallmean no.of insects per trap

Plot A(with barrier)

Plot B(no barrier)

a

a

a

a

a

a

a

b

b

b

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

30 45 60 75 90

Distância (m) da área de brejo

nº

méd

io d

e in

seto

s ca

ptur

ados

Subtalhão A Subtalhão B

Incidence of sharpshooters at increasing distances from the swamp in plots with (A) or without (B) the

trap-plant barrier

Mean No.of insectsper trap

Distance (m) from the vector source (swamp)

Plot A(with barrier)

Plot B(no barrier)

PLOT

B

No barrier

Plot

A

With barrier

Problem: other sources of vectors (besides the swamp)

Trap plant barrier

Source of vectorsSwampy wood

Conclusions

• Trap crop reduces sharpshooter population in the orchard (up to 60 m from border)

• A mixture of plant species is needed (vector diversity; seasonal variation in host plant suitability)

• Compatible with other vector control methods

• More likely to work in small orchards

Bucephalogonia xanthophis

Vernonia condensata(falso-boldo)

Glandular Trichomes

52,5 μm

                          

Attraction of sharpshooters by plant volatilesJ. Maurício Bento –ESALQ/Univ. S. Paulo

Capitate-sessile trichomes of Vernonia condensata. General view of a trichoeme filled with secretion (left), and after it content was released (right) (Bento et al., 2008).

Finantial Support Research Team• Rodrigo N. Marques

• Daniele T. Turati

• Teresinha A. Giustolim

• Matê Lopes

• Pedro T. Yamamoto (Fundecitrus)

• Marcos Felippe (Fundecitrus)