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Copyright 2005, Board of Trustees, University
Ft. Pierce ARC Research Report RL-1978-1 March 1978
EFFECT OF FUNGICIDE, LIME AND FERTILIZE S
ON FUSARIUM CROWN ROT OF TOMATO HU E R
R. M. Sonodal'1/
APR 6' 978
Abstract 1.F.A.Sf Flori
Univ. Of Horic
The effect of different combinations of fungicides, lime, an a e of
nitrogen on Fusarium crown rot of tomato was evaluated using pot grown tomatoes. A
combination of fungicide (either benomyl or captafol), liming and nitrate nitrogen
was most effective in reducing disease symptoms. Symptoms were most severe in treat-
ments receiving ammonia fertilization. Treatments receiving fungicides had reduced
Fusarium crown rot of tomato, incited by Fusarium oxysporum, caused losses in
yield on several farms on sandy soils in southeast Florida (4). So far, chemical
control methods, including fumigation with methyl bromide plus chloropicrin (6),
pre-plant broadcast treatment with sodium azide (6), and post-plant drenches with
benomyl (5) have been ineffective in the field against this disease. Engelhard and
Woltz (1) reported that a combined regime of fungicide, lime and nitrate fertiliza-
tion was effective against Fusarium wilt of chrysanthemum. The following test was
conducted to determine if a similar regime would be effective against Fusarium crown
rot of tomato.
Materials and Methods
Top-soil was obtained from a tomato field in Jupiter, Florida,with a history of
Fusarium crown rot. The population of the pathogen in the soil was determined by
plating soil suspensions on selective media (2), followed by pathogenicity tests on
Walter tomato using Sanchez et al's (3) technique. Twelve randomly selected soil
samples were assayed.
The soil was put into 22 cm plastic pots. Eleven g of Ca (OH)2 was mixed
thoroughly with soil in each pot receiving liming treatment. The standard fertilizer
solution used was 1.5 g KH2PO4 and 0.2 g MgSO4'7H20 per 1. For treatments receiving
nitrate, 3.8 g KNO3 was added to each 1 of standard solution. For treatments re-
ceiving ammonium fertilization 1.5 g NH4NO3 was added per 1 of standard solution.
The nitrate solution and the ammonium nitrate solution contained the same concen-
tration of N. The K concentration of the nitrate solution was 4.4 times as much as
in the ammonia solution. Prior to planting, 200 ml of the solutions were drenched
into the pots. After planting, the pots were watered 2-3 times a week with 200 ml
1/ Associate Professor, University of Florida, Institute of Food and Agricultural
Sciences, Agricultural Research Center, Fort Pierce.
'of the respective solutions. The pots were watered with tap water when necessary.
Floradel tomato seedlings grown in 'speedling' trays were obtained from a
commercial source. After taking seedlings from trays, as much as possible of
planting mix adhering to roots was removed. The procedure resulted in some root
damage. The roots were dipped in either 1000 ppm benomyl (methyl l-(butylcarbamoyl)-
2- benzimidazole carbamate) or 750 ppm captafol (cis-N-((1,1,2,2-tetrachloroethyl)
thio)-4-cyclohexene-1,2-dicarboximide) for treatments receiving fungicide and dis-
tilled water for those not. Prior to planting, 100 ml of the same suspensions were
poured into planting holes.
The planting was made on Nov. 21, 1977. The pH of soil samples collected from
each pot immediately after planting was measured with a Leeds Northrup 7400-A2 meter.
The pots were arranged in a randomized complete block design on black polyethylene
between two greenhouses. A foliar fungicide (mancozeb) and an insecticide (diazinon)
were applied as needed.
On January 4, 1978, plant heights were recorded and fruit harvested and weighed.
The plants were removed from the pots and the stem and root necrosis were made. The
rating system used was 1- no disease; 2- slight necrosis; 3- moderate necrosis;
4- severe necrosis; and 5= plants dead.
Results and Discussion
The mean density of Fusarium crown rot propagules in the soils in the pots was
575 per g.
No necrosis was found in stems and roots of plants receiving no nitrogen ferti-
lization. However, these plants were stunted and did not produce much fruit
(Table 1). One plant in each of treatments 4, 5, 7, 8, and 9 and two plants in treat-
ment 6 were free of lesions. Only three plants, one each, in treatments 10, 11, and
12 were killed by the fungus.
The lowest severity index (Table 1) among plants not stunted by nitrogen de-
fiency was sustained by plants receiving benomyl or captafol, plus lime, plus nitrate
nitrogen. Plants receiving ammonium nitrogen had the highest severity index. The
addition of lime or fungicide to plants receiving ammonium nitrogen did little to
The results indicate that the effect of the three factors, fungicide, liming and
nitrate nitrogen in controlling Fusarium crown rot, is additive. This is similar to
the findings of Engelhard and Woltz (1) for Fusarium wilt of chrysanthemum.
A negative aspect of the tests was that plants receiving fungicides had phyto-
toxicity symptoms and lower yields (Table 1). There was an initial stunting of growth
and some yellowing of leaves with both fungicides.
Although the ammonium treatments had the highest severity index, ammonium treat-
ments'without fungicide had some of the highest yields. Observations of diseased
plants in the field indicate that plants with interior root and stem lesions do not
have significant losses in yield until shoot symptoms are apparent (Sonoda, un-
published data). Except for the three dead plants in this test, none of the other
plants exhibited any shoot symptoms. Plants in the field with severe interior
root and stem necrosis eventually exhibit shoot symptoms, usually at the time that
fruit are mature.
The results indicate that control of Fusarium crown rot is possible in pot
tests with a combined regime of fungicide, nitrate fertilizer and liming. Further
work is necessary to determine if similar results, with reduction in yield losses
due to disease, can be obtained under field conditions. Further work is needed to
determine if the apparent yield reducing effect of the fungicides can be corrected.
Future tests will have to be conducted with fertilizer solutions containing the
same amount of K.
1. Engelhard, A. W. and S. S. Woltz. 1973. Fusarium wilt of Chrysanthemum:
Complete control of symptoms with an integrated fungicide-lime-nitrate
regime. Phytopathology 63:1256-1259.
2. Nash, S. M. and W. C. Snyder. 1962. Quantitative estimations by plate counts
of propagules of the bean root rot Fusarium in field soils.
3. Sanchez, L. E., R. M. Endo, and J. V. Leary. 1975. A rapid technique for
identifying the clones of Fusarium oxysporum f. sp. lycopersici causing
crown and root rot of tomatoes. Phytopathology 65:726-727.
4. Sonoda, R. M. 1976. The occurrence of a Fusarium root rot of tomatoes in
south Florida. Plant Disease Reporter 60:271-274.
5. Sonoda, R. M. 1977. Effect of benomyl drenches on Fusarium crown rot of
tomatoes. Ft. Pierce ARC Research Report RL-1977-2.
6. Sonoda, R. M. and R. T. McMillan, Jr. 1976. Comparison of several wide
spectrum biocides in the field on Fusarium crown rot of tomatoes.
Ft. Pierce ARC Research Report RL-1976-1.
Table 1. Effect of fungicide, nitrogen source and liming on symptom
on Floradel tomatoes!--
severity of Fusarium crown rot
Initial Plant6/ Yield
Nitrogen soil height per plant
No. source Fungicide3/ Limeda/ pH )(cm) (g) DSIZ'
1 none none yes 8.6 a8/ 36 b 34 ef 1.0 a
2 none benomyl yes 8.6 a 42 b 8 f 1.0 a
3 none captafol yes 8.6 a 37 b 6 f 1.0 a
4 KNO3 benomyl yes 8.6 a 66 a 175 cd. 1.1 a
5 KNO3 captafol yes 8.5 a 65 a 245 bcd 1.4 ab
6 KNO3 captafol no 7.6 d 67 a 144 de 1.8 ab
7 KNO3 none yes 8.6 a 62 a 400 a 2.0 abc
8 KNO3 benomyl no 7.6 d 62 a 275 abed 2.3 bcd
9 KNO3 none no 7.7 d 65 a 242 bed 2.3 bed
10 NH4NO3 none yes 8.0 c 64 a 355 ab 2.8 cd
11 NH4NO3 benomyl yes 8.2 b 66 a 169 cd 2.9 cd
12 NH4NO3 none no 7.2 e 60 a 288 abe 3.2 d
1/ Six pots or a single plant per replicate; pots distributed in a randomized complete block design
2/ Nitrogen applied 2-3 times per week in solution.
3/ Roots dipped in 1000 ppm benomyl or 750 ppm captafol prior to planting. Planting hole drenched
with 100 mls of the respective suspensions prior to planting.
4/ Calcium hydroxide thoroughly incorporated at 11 g per pot.
5/ pH measurement made on soil samples from each pot immediately after planting.
6/ At harvest.
7/ Disease severity index 1 -no lesions to 5 = death of plant.
8/ Means followed by the same letter are not significantly different at the 5% level (Duncan's new
multiple range test).