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,2 0 GULF COAST RESEARCH & EDUCATION CENTER
IFAS, UNIVERSITY OF FLORIDA
L 5007 60th Street East
Bradenton, FL 34203
Bradenton GCREC Research Report BRA1986-22 December 1986
EFFECT OF FERTILIZER, LIHE AND ALUH4INUT ON
FUSARIUji WILT OF TOI4ATO
S.S. WOLTZ AND J.P. JONES1
Fusarium wilt of tomato may be reduced in severity by adjustments in soil pH
and inorganic nutrition levels (1, 2, 3, 4). Aluminum (Al) is of potential
interest in the Fusarium disease control procedures for soils since it is a
common soil constituent chemically available more at low pH values and also
has been reported to be specifically inhibitory to some soil fungal
pathogens (3) and may affect microbial competition. The experiment reported
was carried out to develop an understanding of the basis for the effects of
varied soil conditions in increasing or decreasing Fusarium wilt.
Walter tomato plants were set into 5 inch pots (4 plants per pot) containing
virgin EauGallie fine sand, pH 4.8 before amendment. The soil was amended
to include 48 treatments (4 replicates) by using the following "low" and
"high" rates, grams per liter of soil: A12(SO4)3.13H20, 0 and 1.5; CaCO3,
1.25 and 5.0; triple superphosphate (46% P205), 0.3 and 1.2; CuSO4-51120, 0
and 0.03; Fe 138 chelate (Geigy),O and 0.045; and ZnS04.7H20, 0 and 0.09.
iMicronutrient combinations included 1) none, 2) all (Cu + Fe + Hin + Zn) and
individually added micronutrients, 3) Cu, 4) Fe, 5) iln, and 6) Zn.
Nitrogen, potassium and magnesium were furnished in all treatments at the
following rates, g/L soil: NH4NO3, 0.375; I N03, 0.375; and igS04-71i20,
Plants were grown in the greenhouse with day and night temperature of 30 +3
and 24 +2 C respectively. Plants were root-wounded by cutting with a
scalpel and a suspension containing 4.4 x 106 microspores per ml was poured
on the soil surface, 100 ml per pot. Plants were rated for disease after
sufficient symptom development. At the end of the experiment pots were
divided into 4 categories based on disease development and stem chips (top,
mid-stem and bottom) were plated out on potato dextrose agar. The 4
categories were for 4 plants/pot: I = no visible disease, II = 1 plant
diseased, III = 2 plants diseased, and IV = 3 or 4 plants diseased.
1Plant Physiologist and Plant Pathologist, respectively.
Soil aluminum lowered the pH of soil (Table 1) in conjunction with the low
lime rate but did not change the pH very much at the high lime rate. The
overall wilt rating mean for low lime treatments was higher than for high
lime. The differential between low lime and high lime is greater for the
added aluminum treatments. High wilt disease ratings were associated with
higher pH except that the combination of aluminum and high lime reduced
disease in conjunction with low phosphate, probably by causing a deficiency
of phosphorus for the Fusarium.
Low lime was associated with higher disease rating (1.81) than high lime
(0.74). Differences were readily apparent within the high lime portion of
the experiment in response to aluminum, phosphate and minor element
treatments but the low lime treatment produced uniformly high disease.
Aluminum applications decreased the mean disease rating (Table 2). This
effect seems to be an interaction with phosphorus in tying up the element
and depriving the Fusarium and perhaps the tomato plant of required
phosphorus. Extra phosphorus interacted with copper to reduce disease while
with iron, the extra phosphorus increased disease. Combined inclusions of
the 4 minor elements increased disease over the no minor elements control
but only with no aluminum added treatment. Copper and zinc interacted with
phosphate and aluminum to increase disease. Copper caused more disease with
low phosphorus and no added aluminum, while iron had the reverse effect,
interacting with extra phosphorus to increase disease in the absence of
Fusarium was recovered from most chips plated out from the pots with 75 or
1007 disease (Table 3). Decreasingly less chips had Fusarium for the
categories having fewer diseased plants/pot.
This experiment demonstrates the importance of a number of soil chemistry
variables in controlling the host-parasite interactions in Fusarium wilt of
tomato. A few major points are to be made: 1) the interactions of disease
and nutrition for host and parasite make it difficult to explain all
indications; 2) high pH as usual reduces wilt; (3) phosphorus in good supply
supports the pathogenicity of Fusarium; 4) micronutrients are frequently
beneficial to the disease process; and 5) aluminum, a common soil
constituent available at low pH, may interact with other nutrients to
increase or decrease disease.
1. Jones, J.P. and Woltz, S.S. 1972. Effect of soil pH and micronutrient
amendments on Verticillium and Fusarium wilt of tomato. Plant Dis.
2. Jones, J.P. and Woltz, S.S. 1981. Fusarium-incited diseases of tomato
and potato and their control. pp 157-168 In: Nelson, P.E., T.A.
Tousson and R.J. Cook, (eds) Fusarium: Diseases, Biology and
Taxonomy. The Pennsylvania State Univ, Press. University Park. 457
3. Xo, W.H. and Hora, F.X. 1972. Identification of an Al ion as a soil
fungitoxin. Soil Science 113:42-45.
4. Woltz, S.S., and Jones, J.P. 1981. nutritional requirements of
Fusarium oxysporum: Basis for a disease control system. pp 340-349
In: delson, P. E., T. A. Toussoun, and R. J. Cook, (eds) Fusarium:
Diseases, Biology and Taxonomy. The Pennsylvania State University
Press, University Park. 457 pp.
Table 1. Soil pH, soil aluminum and Fusarium wilt mean rating indexes for
Lime 0 Al + Al
phosphorus Soil Soil Wilt Soil Soil Uilt
treatments pH AlY rating pH Al rating
LSD, 5% level for wilt
ZUilt ratings: 0 = no symptoms; 1 = slight symptoms; 2 = moderate symptoms;
3 = severe symptoms; 4 = very severe symptoms; 5 = plant dead.
YExtracted with 1 molar KC1 and expressed as ppm in soil solution.
XLL = low lime; HL = high lime; LP = low phosphate; iP? = high phosphate.
Table 2. LHean Fusarium wilt disease rating per pot of 'Walter' tomato for
the high-lime portion of the experiment.
elements) 0 Al + Al mean
added LP HP ijean LP ? lean minors
None 0.01 0.69 0.75 0.00 0.63 0.32 0.53
iUn, Zn 1.50 1.75 1.63 0.44 0.33 0.54 1.03
Cu 1.25 0.69 0.97 0.19 1.63 0.91 0.94
Fe 0.50 1.44 0.97 0.13 0.75 0.44 0.70
lin 0.69 0.31 0.50 0.31 0.56 0.44 0.47
Zn 0.69 0.75 0.72 0.06 1.44 0.75 0.74
iean 0.91 0.94 0.92 0.19 0.94 0.56
Phosphate means: Low = 0.55; High = 0.94
LSD, Al x P x iHinors = 0.69; Al x P = 0.23; Al x ii = 0.49; Hinors = 0.35; Al
or P = 0.20
zRefer to footnote z, Table 1.
YRefer to footnote x, Table 1.
Table 3. Percentage Fusarium recovery from stem chips for pots graded into
4 disease categories according to numbers of symptomatic plants per pot.
Disease Number of symptomatic Stem sample location
category plants/potz Lower Iiiiddle Upper Hean 7
I 0 73 48 23 48
II 1 81 54 31 55
III 2 86 79 21 62
IV 3 or 4 100 100 96 99
z # plants per pot.