Nonhosts of Xylella fastidiosa that sharpshooters would die for... 
A management strategy based on trap plants Presenters: João S. Lopes, Rodrigo Marques, Daniele Turati

1. 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 the
Interface of citrus orchard
Riparian wood
Source of vectors
(from Purcell)

2. FUNDECITRUS

3. 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

4. Young citrus grove Primary and secondary spread
Older infected grove (inoculum source)
Infected
tree
Healthy
tree

5. H e alt h y n u r se r y t r e e sH e alt h y n u r se r y t r e e s
V e c t orV e c t or
c on t r olc on t r ol
Pr u n in gPr u n in g
Rog u in gRog u in g
CVC
management

6. Problems with vector control
in citrus
• High cost of insecticides
• Environmental impact
• Perennial crop
• Multiple vector species
• External sources of vectors

7. Young grove
Neighboring
grove
Swamp or Riparian Wood
Immigration of sharpshooters toImmigration of sharpshooters to
the citrus grovethe citrus grove

8. Trap crop
Young grove
Neighboring
grove
Riparian wood or swamp
T
r
a
p
c
r
o
p
Inseticide
treatment
Establishment of trap cropEstablishment of trap crop

9. 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

10. Why search for nonhosts of X.
fastidiosa?
• Safe trap plants – not a source of
inoculum
• Rearing healthy sharpshooters (other
studies)

11. 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 toSearch for attractive host plants to
sharpshooters in S.Paulo State, Brazilsharpshooters in S.Paulo State, Brazil
Studies

12. Observations of sharpshooters in natural habitats
Northern São Paulo State (Giustolim et al.)
SwampSwamp
Riparian woodsRiparian woods
““Cerrado”Cerrado”

13. Acrogonia citrina
Bucephalogonia
xanthophis
Dilobopterus
costalimai
Oncometopia
facialis
13
17
15
21
10
8
12
13
Sharpshooter No. familiesNº species
Host plant
Total 40 20
* No. habitats surveyed: 6
** No. plant species surveyed: 107
(Giustolin et al.)

14. Families of host plants
Main vector species Bucephalogonia xanthophis
Sharpshooters nymphs

15. Aloysia virgata –Aloysia virgata – visited by various sharpshootersvisited by various sharpshooters
AcrogoniaAcrogonia sp.sp. D. costalimaiD. costalimai
O. facialisO. facialis
PseudometopiaPseudometopia sp.sp.
M. leucomelasM. leucomelas

16. Croton floribundus –Croton floribundus – visited by various sharpshootersvisited by various sharpshooters
O. facialisO. facialis
PseudometopiaPseudometopia sp.sp.
AcrogoniaAcrogonia sp.sp.
HomolodiscaHomolodisca sp.sp.
MacugonaliaMacugonalia
leucomelasleucomelas

17. Vernonia sp1. Vernonia sp2.Pterocaulon lanatum Baccharis sp.
Asteraceae
Most visited by Bucephalogonia xanthophis
Verbenaceae – Lantana camara
Oncometopia facialis
Oncometopia facialis

18. Observations of sharpshooters in urban areas
‘boldo’
Vernonia condensata
Hibiscus rosa-sinensis
Datura repens

19. Choice test in the greenhouse (cages)
citrus X other hosts
How attractive are the host plants??

20. Choice study under field conditions
citrus X other hosts
Piracicaba, SP, Brazil
(June/04 - Feb/08)
Host species planted in area
adjacent to riparian wood

21. Mean number of sharpshooters observed on various host plants in area
adjacent to a riparian wood. Piracicaba, SP, Brazil
Turati et al.
No. of
sharpshooters
Vernonia condensata
Citrus
Laranja
Paud´alho
Lantana
Pingodeouro
Lixeira
Croton
Boldo
Hibisco
Bucephalogonia xanthophis
Paratona gratiosa
Macugonalia leucomelas
Catagonalia conjunctula
Scopogonalia subolivacea
Sibovia sagata
Macugonalia cavifrons
Acrogonia citrina
Dilobopterus costalimai
0
0.5
1
1.5
2
2.5
3
Host plants
Sharpshooter
species
Aloysia
virgata
Datura
repens
Lantana
camara Hibiscus

22. Mean number of Oncometopia facialis observed on various host plants in
area adjacent to a riparian wood. Piracicaba, SP, Brazil.
Turati et al.
No. of
sharpshooters
Seasons
Host plants
Inverno04
Verão04/05
Outono05
Verão05/06
Inverno06
Primavera06
Verão06/07
Outono07
Primavera07
Verão07/08
Laranja
Pau d´alho
Lixeira
Hibisco
Croton
Boldo
Lantana
0
5
10
15
20
25
30
35
40
Lantana camara
Aloysia
virgata
Vernonia condensata
Croton
floribundus
Citrus sinensis
Oncometopia facialis

23. Most attractive host species to the
sharpshooter complex
• Vernonia condensata (‘boldo’)
• Lantana camara
• Aloysia virgata
• Croton floribundus
• Datura repens

24. Are there X. fastidiosa hosts among
preferred hosts of citrus sharpshooters ?
Symptoms
Mechanical inoculation of X.
fastidiosa
Culture-4 months
Host plant
Aloysiavirgata
Baccharis sp.
Cedrelaodorata
Crotonfloribundus
Gallesiaintegrifolia
Gochnatiapolymorpha
Ilexteezans
Lantanacamara
Lueheapaniculata
Pterocaulonlanatum
Styraxferrugineus
Vernoniasp1.
Vernonia sp2.
ND ND
ND ND
ND 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
0/20
ND

25. Mechanical inoculation ofMechanical inoculation of V. condensataV. condensata
withwith X. fastidiosaX. fastidiosa
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 0/50/5
2/10 4/10 7/102/10 4/10 7/10
(Marucci et al. 2003)

26. Plant 7 14
Vernonia condensataVernonia condensata
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 ofMechanical inoculation of V. condensataV. condensata
withwith X. fastidiosaX. fastidiosa
(Marucci et al. 2003)

27. Rearing healthy vectorsRearing healthy vectors
- Vernonia condensata -- Vernonia condensata -
Rodrigo
Almeida (1999)

28. 0
10
20
30
40
50
60
70
80
90
Vernonia
condensata
V. condensata and
Citrus
Citrus
NymphalViability(%)
Oncometopia facialis Dilobopterus costalimais
Vernonia condensata as a developmental host
for sharpshooters
Milanez et al. (2001)

29. Testing trap plants
in a citrus grove
Oxford Farm
Gavião Peixoto, SP
(Oct/2004)
Source of vectors
Swampy wood
Citrus grove
Trap plant barrier

30. 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)

31. Establishing the trap-plant barrier
10/19/04 (planting date)
12/27/04 (2 months later)

32. Plant height (3 months after planting)
1,0 m
0
50
100
150
200
250
C.floribundus
C
.urucurana
G
.integrifolia
A.virgata
T.guianensis
S.alataG
.unifolia
M
.caesalpineafolia
B.dracunculifoliaL.cam
ara
V.polyanthes
V.condensata
E.laevigatum
D.repens
AlturaFinal(cm)
Plant
height
(cm)

33. Dec/05 (14 months after planting)
Establishing the trap-plant barrier
Treatment with
imidacloprid

34. 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

35. b
a
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
Subtalhão A Subtalhão B
nºdeinsetoscapturados
Incidence of sharpshooters in plots with (A) or
without (B) the trap-plant barrier
Overall
mean no.
of insects
per trap
Plot A
(with
barrier)
Plot B
(no barrier)

36. 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
nºmédiodeinsetoscapturados
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 insects
per trap
Distance (m) from the vector source (swamp)
Plot A
(with
barrier)
Plot B
(no barrier)

37. PLOT
B
No barrier
Plot
A
With barrier
Problem: other sources of vectors (besides the swamp)
Trap plant barrier
Source of vectors
Swampy wood

38. 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

39. Bucephalogonia xanthophis
Vernonia condensata
(falso-boldo)
Glandular
Trichomes
52,5 μm
Attraction of sharpshooters by plant volatiles
J. Maurício Bento –ESALQ/Univ. S. Paulo

40. 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).

41. Finantial Support Research Team
• Rodrigo N. Marques
• Daniele T. Turati
• Teresinha A. Giustolim
• Matê Lopes
• Pedro T. Yamamoto
(Fundecitrus)
• Marcos Felippe
(Fundecitrus)