Hector and Alicia Zubrzycki
(INTA. Bella Vista. Corrientes)
for
assistance in locating affected groves and for help in collecting
samples.
The technical
assistance
of Mary H. Collins , Neil L.
Berger
and
Denise
Fardelmann
is gratefuUy
2.
3.
4.
5.
6.
7.
9.
Brlansky, R. H., L. W. Tirnmer, R. F. Lee and J. H. Graham. 1984.
Relatíonship of xylern plugging to water uptake in citrus affected
by citrus blight. Phytopathology (submitted).
Cohen, M., R. R. Pelo si and R. H. Brlansky. 1983. Nature and
location of xylem blockage structures in trees with citrus blight.
Phy topathology 73: 1.125-1.130.
Fischer, H. U., L. W. Tirnmer and G. W. MüJler. 1983. Comparison
of decJinamiento, blight, dechuio , and marchitamiento repentino
by use of uniform examinaton methods In: S. M. Garnsey, L. W.
Timmer and J. A. Dodds (eds.). Proc, 9th Conf. Int. Organ: Citrus
Virol, IOCV. Riverside (in press).
Graham, J. H., L. W. Tirnmer and R. F. Lee. 1983. Comparison of
zinc, water uptake by gravity infusion and syrínge inject ion tests
for diagnosis of citrus blight. Proc. F/a. St ate Hort. Soco 96: 45-47:
Lee, R. F., L. J. Marais, L. W. Tirnmer and J. H. Graham. 1984.
Syringe injection of water into the trunk: a rapid diagnostic test
for citrus blight , Plant Dis, (in press).
Lima, J. E. O. and A. S. Borducchi. 1982. Observations on citrus
blight in Brazil. Proc. F7a. State Hort, Soc . 95:72-75.
Pagui, O. R., Y. S. Coelho and H. P. Santos Filho. 1983. Citrus
decline in the State of Bahia. Brazil: occurrencc and responses
to blight diagnostic tests. In: S. M. Garnse y , L. W. Timmer and
PERPETUATION
ross EDUARDO
8.
acknowledged.
Literature cited
1.
J. A. Dodds (eds.). Proc. 9rn Conf
10.
11.
12.
13.
14.
Int. Organ. Citrus ViTol.IOCV.
R iverside (in press).
Pujol, A. R., R. E. Schwarz, M. V. Fernandez-Valieta and D. S.
Rodriguez. 1972. A decline of citrus on trifoliata orange associated
with tristeza. Pages 154-156. In: W. C. Price (ed.). Proc. 5th Conf.
Int, Organ. Citrus Virol. University
of Florida Press, Gainesville.
Rossetti, V., H. K. Wu tscher , J. F. Childs, O. Rodriguez. C. S.
Moreira, G. W. Milller, H. S. Prates, J. D. De Negri and A. Greve.
1980. Decline of citrus trees in the State of 530 Paulo , Brazil.
Pages 251-259. In: E. C. Calavan, S~~ Carnsey and L. W. Timmer
(eds.), Proc. 8th Conf Int. Organ. Citrus Virol. IOCV. Riverside.
Schwarz, R. E.. T. Arguelles, P. Monsted, H. Wutscher and L.
Terrnachuka. 1980. Studies on the cause of the fruta bolita or
declinamiento disease of citrus in Argentina. Pages 241-250. In:
E. C. Calavan, S. M. Garnsey and L. W. Tirnmer (eds.). Proc. 8th
Con]. Int. Organ. Citrus Virol. IOCV. Riverside.
Smith, P. F. and H. J. Reitz. 1977. A review of the nature and
history of citrus blight in Florida. Proc. Int. Soco Citriculture
3: 88 i-884.
Wutscher, H. K., H. G. Campiglia, C. Hardesty and A. A. Salibe.
1977. Sirnilarities between marchitamiento repentino disease in
Uruguay and Argentina and blight of citrus in Florida. Proc. Fla.
State Hort. Soc. 90: 81-84.
Wutscher, H. K., M. Cohen and R. H. Young. 1977. Zinc and
water-soluble phenolic levels in the wood for the diagnosis of
citrus blight.P/antDis. Rptr, 61:572-576.
Wutscher, H. K., R. E. Schwarz , H. G. Campiglia , C. S. Moreira
and V. Rosset ti, 1980. BlightIike citrus tree declines in South
America and South Africa. HortScience 15: 588-590.
ATTEMPT -OF DECLlNIO
O. DE LIMA
CNPMF - EMBRAPA, CJTRJC- JAC, CP. 28
13100 - Campinas, SP, Brazil
LUIZ AUGUSTO B. C. DE VASCONCELLOS
Horticultura, ESALQ-USP, CP 9
13400 - Piracicaba,SP, Brazil
RUTER HIROCE
Fert. Solo e Nu tr. Plantas - lA C, CP 28
13100 - Campinas, SP, Brazil
OF CITRUS
that a dechnio-related zinc-accumulatíon factor (ZAF) could be
perpetuated
with a single bud of a declínio-affected
tree.
However, no visual symptom of declínio was detected on
propagated plants. Our objective was to study these declínio
perpetuations at 6.5 years of age, in relation to declmio-related
characteristics like trunk water-injection rate (WIR). root waterconductivity (RWC), and levels of zinc and potassium in the
trunk, in order to verify perpetuation of declínio or declíniorelated characteristics.
ANTONIO S. BORDUCCHI
Faz. Sete Lagoas Agr. SA, B. Martinho Prado
13480 - Mogi-Gua{u, SP, Brazil
Additional index words. Citrus decline, blight.
Abstract. Healthy and decHnio-affected 'Valencia' sweet
orange (Citrus sinensis [L.] Osbeck) budwood were propagated
on rangpur lime (e. limonia Osbeck) and sweet orange rootstocks, and the trees planted in 1977. When the trees were
6.6 years olds, 31% of the decHnio-budwood trees and 25% of
the healthy budwood trees on rangpur lime rootstock began
to show decHnio-related zinc accumulation and reduced waterinjection rate in the trunk, followed by visual symptoms of
decUnio. None of the trees on sweet orange rootstock showed
visual symptoms of decHnio. There was no difference in average
trunk
water~njection
rateo root water-conductivity,
zinc
content of bark and wood of the trunk, tree height and trunk
circumference between declínio- and healthy-budwood trees
on rangpur lime or sweet orange rootstocks.
Material and Methods
Dechruo-affected
and healthy
'Valencia'
sweet orange
budwood were propagated on rangpur lime and sweet orange
rootstocks by "t " budding. Four healthy-budwood
trees on
each rootstock,
13 decJínio-budwood
trees on rangpur lime.
and 7 decJínio-budwood
trees on sweet orange were planted
in April, 1977 at Mogi-Guacu, SP. The area has significan!
incidence of declmío? , bu t experimental trees were planted on
new land, at least l km from the nearest declínio-affected trees.
Propagated plants were studied at 4 and 5.5 years of age and
the results published elsewhere". When trees were 6.5 years old.
the following declinio-related parameters were evaluated: trunk
WIR, RWC, levels ofzinc and potassium in the t runk, tree height.
and trunk circumference. Water-injection rate was determined
Table 1 Zinc centent of the trunk bark of 'Valencia' trees propagated
from and declínio-affected budwood on rangpur lime (ra I and
sweet orange (sw) rootstocks
Zn (¡J.g/g.
Sampling year uree age i
Introduction
Declínio is a citrus-tree decline of unknown etiology which
occurs in Brazil", lnvolvement of pathogenic organisms in the
cause of declínio would be indicated by its transmission to
unaffected trees, or its perpetuation. through budding. Results
of transmission and perpetuation
at ternpts. however , are still
inconclusíve+":".
Higher levels of zinc in the trunk bark. a characteristic of
declínio-affected
trees, were detected in young trees propagated
from declínio-affected budwood at 4 and 5.5 years of age, when
compared to trees from healthy budwood".
This indicated
374
Budw ood
source/
Healthy
Declínio
Healthy
Declínio
z
y
x
Root st ock
1981 (4 yr}
1982 (5.5 yr)
ra
ra
sw
sw
37 bY
59 a
x
58
93
68
52
b
a
b
b
1983 (6.5 yr
í
103 a
98 a
43 b
44 b
Four to 8 t ree s per budwood source per year.
Mean separation within years by Duncan's múltiple range test. 5% level
1981) and 1% level (1982 and 1983).
Not sampled.
Proc. lnt.
SOCo
Citriculture, /984. Vol. /
Table 2 Trunk circumference,
tree height, trunk water-injection
trunk wood and bark of 6.5-year-old
'Valencia'
trees
declúiio-affected
budwood.
Budwood
source/
Healthy
Dechnio
Healthy
Dec1ínio
Trunk
Rootstock
ra
ra
sw
sw
Height
(m)
circo (cm)
49 ± I
47 ± 2
3.6
3.4
41 ± 2
38 b 1
3.0 ± 0.1
3.0 ± 0.1
±
±
0.1
O. I
rate (WIR). root water-conductivity
(RWC) and zinc and po tassium levels in the
propagated
on rangpur lime (ra) and sweet orange (sw) rootstock
frorn healthy and
WIRY
Zn (¡.¡g . g-I)
RWC
(mI. S-I)
(mI. cm - •. ml " I )
57 ± 4
51 ± 9
59 ± 5
61 ± 4
0.6 ± 0.2
0.8 ± 0.1
0.9 ± 0.2
1.2±0.1
Wood
3.0
4.3
±
±
1.6
1.2
1.4
1.2
±
±
0.2
0.2
K (%)
Bark
103 ± 6
98 ± 11
43 ± 5
44 ± 5
Wood
0.21
0.21
0.21
0.19
:!:
i
i
±
0.02
0.02
0.02
0.01
zy Four healthy trees for each rootstock, 8 declínío-trees for ra and 7 for sw.
x
Syringe-with-lever method (see tex t).
Mean ± SE.
Table 3 Rating of Ded ínio visual symptoms, trunk wa ter-injectio n ra te (WIR), root water conductivity (RWC), and zinc and potassium levels in the
trunk wood and bark of 6.5-year-old 'Valencia' trees propagated from healthy and declinio-affected budwood on rangpur lime rootstock
Budwood
source
Declínio
rating-
WIRY
(mI. S-I)
Healthy
healthy (3)
moderate
healthy (9)
early
moderate
advanced
advanced
0.8 z 0.0
0.1
Declfnio
z
y
x
RWC
(mI. cm " ". min-I)
1.1 ± 0.1
0.2
0.1
0.1
0.1
54
64
60
_:\
:!:
±
14
5
Zn (¡.¡g. g-I)
Wood
1.5
7.7
±
O. I
1.6
9.6
12.0
6.4
10.8
±
0.3
K (%)
Bark
101
I 1I
79
126
90
149
204
Wood
±
8
±
4
0.19 ± 0.01
0.25
0.18 ± 0.01
0.30
0.25
0.27
0.32
Individual trees, except for healthy trees where number of trees po oled tor mean ± SE calculation ís indicated in parentheses.
Syringe-with-lever method (see tex t).
Not determined.
by the syringe-wíth-lever method". Injection was made through
a 3.2 x 35 mm hole drilled in the trunk, 5-30 cm above the bud
union. The syringe was filled with 7 mi 01' water. injection
attempted for 5 s, and WIR (mi. S-I) calculated. Declmioaffected trees show rates around 0.1 mi. s -1 , while healthy trees
show rates several times higher. Root water conductivíty was
determined by ·connecting 0.5-1.5 cm-diameter root pieces to
a vacuum pump and puUing water through them". Declínio
trees show reduced RWC. Zinc and potassium levels were
determined on 3 x 3 cm bark-patch sarnples' ..and wood samples
extracted with a half-inch bit and manual drill8,9 • Accumulation
of zinc in the trunk bark and wood, and of potassium in the
trunk wood are characteristics of declínio-affected trees.
Results and Discussion
There was no difference in zinc levels of dechnio-affected
or healthy budwood propagated on rangpur lime or sweet orange
rootstocks, when trees were 6.5 years old (Table 1). The same
happened for other characteristics studied, trunk circumference ,
tree height, WIR, RWC, and potassium levels (Table 2). Trees
which originated from declínio-affected budwood budded on
rangpur lime had shown higher zinc levels than healthy-budwood
trees in 1981 and 1982 samples, when trees were 4 and 5.5 years
old, respectively? (Table 1). No such difference existed for trees
on sweet orange. The authors had concluded then that a ZAF
could have been perpetuated, but nothing could be said about
the perpetuation of declínio itself, since there were no visual
symptoms of decline on propagated plants". Current results.
however, do not confirm ZAF perpetuation (Table 1l.
Four out of 13 declínio-budwood trees (31%) had reduced
trunk WIR, RWC, and showed accumulation of zinc and
potassium in the trunk, followed by visual symptoms of dechnio
at 6.5 years of age (Table 3). Simultaneously, 1 out of 4 healthybudwood trees (25%) showed declmio-related characteristics.
Proc. Int. Soco Citricu/ture. /984. Vol. l.
Perpetuation of declínio or any of the dechruo-related
characteristics studied, therefore, cannot be assumed from
present results. Attempts to perpetuate blight , a citrus-tree
decline of Florida, US, similar to declínio, have also been
unsuccessful": 10. Our resu1ts, however, concern a small number
of young trees in a single location. Continuous observation and
testing of these propagated plants, as well as replication of the
experiment with a greater number of trees in other locations are
recommended.
Literature cited
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Albrigo, L. G., and R. H. Young. 1979. Citrus tree decline complex
and diagnostic identification of blight. Proc, Fla. State Hort. Soc.
92: 61-63.
Lima, J. E. O. de, and A. S. Borducchi. 1982. Observations on
citrus blight in Sáo Paulo, Brazil. Proc, Fla, Sta te Hort. Soco 95:
72-75.
Lima. J. E. O. de, L. A. B. C. de VasconceUos, N. Guírado, and
J. Pompeu Jr. 1984. Use of a simple device to test the specificity
of the water-injection test for declínio of citrus. Proc. Int. Soco
Citriculture (in press).
Prates, H. S., N. Guirado and G. W. Müller. 1983. Declinio dos
citros no Estado de Slio Paulo. l..aranja. 4: 147-164.
Rodriguez, O., V. Rossetti, G. W. Müller, C. S. Moreira, H. S. Prates,
J. D. De Negri and A. Greve. 1979. Declínio de plantas cítricas em
S40 Paulo. Anais V. Congr. Soco Brasileira Fruticultura 927·932.
Rosse tti , V. 1982. Declínio de plantas cítricas. Testes diagnósticos
e tentativas de controle.l..aranja 3: 157-172.
Smith, P. F., and H. J. Reitz. 1977. A review of the nature and
history of citrus blight in Florida. Proc. Int. Soco Citriculture
3: 881-884.
Wutscher, H. K., and C. Hardesty. 1979. Concentrations of 14
elements in tissues of blight-affected and healthy 'Valencia' orange
trees.1. Amer. Soco Hort. Se;' 104: 9-11.
Wutscher, H. K., M. Cohen and R. H. Young. 1977. Zinc and
water-soluble phenolic leveIs in the wood for the diagnosis of citrus
blight.Plant Dis: Reptr. 61: 572-576.
Wutscher. H. K.• C. O. Youtsey , P. F. Smith. and M. Cohen. 1983.
Negativo results in citrus blight transmission tests. Proc. Fla. State
Hort. Soc. (in press).
375