EVALUATION OF VYDATETM IN COMBINATION WITH SOIL FUMIGATION
ON TOMATO FOR YIELD INCREASE AND NEMATODE CONTROL
J. A. J. Desaeger, A. S. Csinos
University of Georgia
Dept. of Plant Pathology
P.O. Box 748
Tifton, GA 31793
Introduction
Oxamyl (Vydate, Dupont Chemicals) is an oxime carbamate used to control
nematodes, mites and insects. A systemic pesticide, it is suggested for use as a pre-plant,
at-plant and post-plant treatment. Oxamyl is used in a variety of formulations and is
currently one of the only available post-plant nematicides registered for vegetables in the
southeastern US. Although Vydate will not be acceptable to farmers as a stand-alone
treatment for nematode control, it may have potential as a post-plant application
following pre-plant soil fumigation. In the past, we often observed more vigorous stands
and higher vegetable yields when fumigation was followed by Vydate applications.
The following test was set up to evaluate the effect of two rates of Vydate on nematode
damage and fruit yield of tomato in combination with soil fumigation with methyl
bromide (+ chloropicrin) and metam sodium (+ chloropicrin).
Materials and Methods
The study was located at the Blackshank Farm, CPES, Tifton, GA. The area had a
history of soybeans, tobacco, and assorted vegetables. The area was prepared using all
current University of Georgia Extension Service recommendations. The plot design was a
split plot design with fumigants as main treatments and Vydate drip applications as
sub-treatments. Plots were arranged in randomized complete blocks consisting of single
bed plots replicated five times. Each plot was 30 feet long and 30 in wide
On 1 March, 2004, the soil fumigants methyl bromide (67% methyl bromide +
33% chloropicrin chisel-injected at 300 lbs/A) and metam sodium (sprayed at 37.5 gal/A)
and chloropicrin (chisel-injected at 100 lbs/A) were applied and all test plots were
covered with black polyethylene mulch with drip tape in the center of the bed
approximately 1 in. deep. Vydate was applied at planting (March 26), and two and four
weeks post plant through the drip tape at a rate of 2 and 4 qts/A per application (Table1).
Tomato seedlings, cv. Amelia, were produced in nutrient tray system to the 4-leaf
stage. A single tomato was transplanted using a mechanical type transplanter, which cuts
holes in the plastic just ahead of the planters in the center of the plastic bed adjacent to
the drip tape on March 26. Plant spacing was 18 in.
As per the recommendation of the University Of Georgia Extension service, all
plots received 700 lbs. of fertilizer (10-10-10) incorporated prior to planting. Additional
fertilizer was added biweekly in the form of liquid fertilizer (4-0-8 at 4 lbs N/day)
injected through the irrigation tubing during the growing season. All plots were sprayed
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with Bravo 720 (2 pts/A on 15 April, 7 and 17 May), Quadris (10 oz/A on 26 April) for
control of foliar diseases, and Avaunt (3 oz./A on 15 April), Lannate (1 pt/A on 26 April
and 7 and 28 May) and Asana XL (10 oz./A on 17 May) for insect control.
Stand counts were made to record live plants and plant vigor ratings were done
starting at 14 days after planting. Plant vigor was rated on a 1 to 10 scale, 10 representing
live and healthy plants and 1 representing dead plants.
Twelve cores of soil, 2.5-cm-diam × 25-cm-deep, were collected from the center
of each plot before fumigation (24 February), at planting (26 March) and at harvest (8
July). Nematodes were extracted from a 150-cm3 soil sub-sample using a centrifugal
sugar flotation technique, except at planting when they were extracted in Baermann pans
(to capture only active nematodes). On 18 May (at flowering stage) an early root gall
evaluation was done on three plants per plot using a 0 to 10 scale, whereby, 0 = no galls,
1 = very few small galls, 2 = numerous small galls, 3 = numerous small galls of which
some are grown together, 4 = numerous small and some big galls, 5 = 25 % of roots
severely galled, 6 = 50 % of roots severely galled, 7 =75 % of roots severely galled, 8 =
no healthy roots but plant is still green, 9 = roots rotting and plant dying, 10 = plant and
roots dead. Again following final harvest on 1 July ten plants per plot were evaluated for
root galls using that same scale.
Plant weights (root+shoot) were recorded at flowering stage of tomato (18 May)
on three plants per plot. All tomato fruits were hand-harvested from the 15-ft center area
of each bed (10 plants per plot). Each harvest was separated into marketable and cull
fruits, counted, and weighed. There were a total of three harvests, on 8, 17, and 23 June.
White mold was fairly common in the test and incidence and number of wilted
plants were recorded.
All data collected was analyzed with an analysis of variance (P = 0.05) and means
were separated using Duncan's Multiple range test.
Summary
Plant vigor and plant weight (data not given) of tomato was similar for all
treatments (Table 1). Gall indices at flowering and harvest of tomato were low for all
treatments, including the non-treated control (Table 1). Although significant root-knot
nematode soil populations were found before fumigation, very low soil populations as
well as root gall indices were found afterwards (Tables 2, 3, 4). It is not clear why this
was the case, but possibly the high population of predatory nematodes (Mononchids) that
was found throughout the test site may have had an impact (Tables 2, 4). Therefore it was
not possible to observe any effect of fumigants or oxamyl on root-knot nematode.
Oxamyl, however, irrespective of application rate, did reduce soil populations of stubby
root nematodes at harvest.
Excellent tomato growth was observed throughout the test. Total marketable yield
showed only minor differences among fumigants and was generally not significantly
affected by oxamyl applications or rates (Tables 5, 6). However, marketable number of
tomato was reduced by oxamyl applications, in particular for the second harvest (Table
5). Lowest total marketable tomato weight was observed in non-treated plots. Also, the
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highest application rate of oxamyl, irrespective of the fumigant used, did result in
numerically greater yield weight at the third and final tomato harvest (Table 6).
Acknowledgments
The authors wish to thank DuPont Chemical for financial support, Also, Jimmy
Laska, Unessee Hargett, Don Hickey, Lewis Mullis, Chris Williamson and Justin Pate for
technical support.
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Table 1. Effects of soil fumigation with and without oxamyl drip applications on plant vigor, white mold infection and rootgall indices of tomato cv. Amelia, spring 2004, Black Shank Farm Tifton, GA.
Fumigation a
Plant vigor c
Rate/
Oxamyl
White Mold
Wilt
Root gall index d
b
/acre
(0-10)
acre
(1-10)
(plants / plot)
Methyl bromide 300 lbs
Methyl bromide 300 lbs
Methyl bromide 300 lbs
Metam sodium + 37.5 G + 100
chloropicrin
lbs
Metam sodium + 37.5 G + 100
chloropicrin
lbs
Metam sodium + 37.5 G + 100
chloropicrin
lbs
Non-Treated
N/A
F probability fumigation effect
F probability oxamyl effect
No
2 Qts
4 Qts
No
April 10
9.0
8.8
8.7
9.7
April 24
9.2
9.2
9.1
8.9
May 7
9.6
9.5
9.2
9.1
June 2
0
0
0
0
June 15
0
0
0
0
June 23
0b
1 ab
1b
0b
May 18
0
0
0
0
July 1
0
0
0
0
2 Qts
8.9
8.7
8.9
0
1
2 ab
0
0
4 Qts
8.7
8.6
8.8
0
0
0b
0
0
No
8.7
NS
8.4
NS
8.7
NS
1
NS
2
NS
4a
NS
0.3
NS
0.2
NS
NS
NS
NS
NS
NS
NS
NS
NS
a
Fumigant treatments were applied on March 1; beds were covered with plastic mulch immediately following chisel fumigation;
Oxamyl was applied through the drip tape at planting (March 26) and 2 and 4 weeks afterwards; c Vigor was done a 1-10 scale with
10= live and healthy plants and 1=dead plants; d Root gall index 0-10 scale whereby, 0 = no galls, 1 = very few small galls, 2 =
numerous small galls, 3 = numerous small galls of which some are grown together, 4 = numerous small and some big galls, 5 = 25 %
of roots severely galled, 6 = 50 % of roots severely galled, 7 =75 % of roots severely galled, 8 = no healthy roots but plant is still
green, 9 = roots rotting and plant dying, 10 = plant and roots dead. Data are means of five replications. Means in the same column
followed by the same letter are not different (P = 0.05) according to Duncan’s multiple range test; no letters indicate non-significant
difference; NS = not significant (P>0.10).
b
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Table 2. Populations of plant-parasitic and free-living nematodes before fumigation of tomato cv. Amelia, spring 2004,
Black Shank Farm Tifton.
Fumigation a
Methyl bromide (67-33)
Methyl bromide (67-33)
Methyl bromide (67-33)
Metam sodium + chloropicrin
Metam sodium + chloropicrin
Metam sodium + chloropicrin
Non-Treated
Rate / acre
300 lbs
300 lbs
300 lbs
37.5 G + 100 lbs
37.5 G + 100 lbs
37.5 G + 100 lbs
N/A
Oxamyl b
No
2 Qts/A
4 Qts/A
No
2 Qts/A
4 Qts/A
No
Pre-fumigation nematode soil populations (per 150 cc soil)
RKN
SRN
RN
FLN
MON
80
46
60
62
124
142
79
16
10
12
18
16
18
12
0
0
4
0
0
0
2
708
1016
904
978
864
920
1066
52
90
100
70
108
86
66
Nematode samples were collected on February 24 (before fumigation); RKN = Root-knot nematode (Meloidogyne spp.); SRN =
Stubby root nematode (Trichodoridae); RN = Ring nematodes (Criconemoides spp.); FLN = Free-living nematodes (bacterial-feeding,
fungal-feeding and predatory nematodes); MON= Mononchid (predatory) nematodes
Data are means of five replications. Means in the same column followed by the same letter are not different (P = 0.05) according to
Duncan’s multiple range test; no letters indicate non-significant difference; NS = not significant (P>0.10).
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Table 3. Populations of plant-parasitic and free-living nematodes at planting of tomato cv. Amelia, spring 2004
Black Shank Farm Tifton.
Fumigation a
Methyl bromide (67-33)
Methyl bromide (67-33)
Methyl bromide (67-33)
Metam sodium + chloropicrin
Metam sodium + chloropicrin
Metam sodium + chloropicrin
Non-Treated
Rate / acre
300 lbs
300 lbs
300 lbs
37.5 G + 100 lbs
37.5 G + 100 lbs
37.5 G + 100 lbs
N/A
Oxamyl
No
2 Qts/A
4 Qts/A
No
2 Qts/A
4 Qts/A
No
a
At planting nematode soil populations (per 150 cc soil)
RKN
SRN
RN
FLN
MON
0
0
2
0
0
0
0
2
0
0
2
0
0
8
0
0
0
0
0
0
0
146 b
188 b
276 ab
292 ab
222 b
340 ab
959 a
0
1
0
0
8
6
5
Fumigant treatments were applied on March 1; beds were covered with plastic mulch immediately following chisel fumigation;
Nematode samples were collected on March 26 (before oxamyl application); RKN = Root-knot nematode (Meloidogyne spp.); SRN =
Stubby root nematode (Trichodoridae); RN = Ring nematodes (Criconemoides spp.); FLN = Free-living nematodes (bacterial-feeding,
fungal-feeding and predatory nematodes).
Data are means of five replications. Means in the same column followed by the same letter are not different (P = 0.05) according to
Duncan’s multiple range test; no letters indicate non-significant difference; NS = not significant (P>0.10).
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Table 4. Populations of plant-parasitic and free-living nematodes at harvest of tomato cv. Amelia, spring 2004
Black Shank Farm Tifton.
Fumigation a
Rate / acre
Oxamyl b
At harvest nematode soil populations (per
150 cc soil)
RKN
SRN
RN
FLN
MON
0
0
0
0
0
0
20
46 a
6b
10 b
26 ab
0b
8b
30 ab
2
0
0
0
0
0
3
564 ab
319 ab
368 ab
536 ab
290 b
364 ab
664 a
22
26
35
40
14
21
61
F probability fumigation
0.02
NS
NS
NS
NS
F probability oxamyl
NS
0.01
NS
NS
NS
Methyl bromide (67-33)
Methyl bromide (67-33)
Methyl bromide (67-33)
Metam sodium + chloropicrin
Metam sodium + chloropicrin
Metam sodium + chloropicrin
Non-Treated
300 lbs
300 lbs
300 lbs
37.5 G + 100 lbs
37.5 G + 100 lbs
37.5 G + 100 lbs
N/A
No
2 Qts/A
4 Qts/A
No
2 Qts/A
4 Qts/A
No
a
Fumigant treatments were applied on March 28; beds were covered with plastic mulch immediately following chisel fumigation;
Oxamyl was applied through the drip tape at planting (March 26) and 2 and 4 weeks afterwards.
Nematode samples were collected on July 8; RKN = Root-knot nematode (Meloidogyne spp.); SRN = Stubby root nematode
(Trichodoridae); RN = Ring nematodes (Criconemoides spp.); FLN = Free-living nematodes (bacterial-feeding, fungal-feeding and
predatory nematodes); MON= Mononchid (predatory) nematodes.
Data are means of five replications. Means in the same column followed by the same letter are not different (P = 0.05) according to
Duncan’s multiple range test; no letters indicate non-significant difference; NS = not significant (P>0.10).
b
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Table 5. Effects of soil fumigation with and without oxamyl drip applications on yield tomato cv. Amelia, spring 2004,
Black Shank Farm Tifton, GA.
Fumigation a
Methyl bromide (67-33)
Methyl bromide (67-33)
Methyl bromide (67-33)
Metam sodium + chloropicrin
Metam sodium + chloropicrin
Metam sodium + chloropicrin
Non-Treated
Rate / acre
300 lbs
300 lbs
300 lbs
37.5 G + 100 lbs
37.5 G + 100 lbs
37.5 G + 100 lbs
N/A
Oxamyl b
Marketable fruits (No)
No
2 Qts/A
4 Qts/A
No
2 Qts/A
4 Qts/A
No
Yield 1
(June 8)
16 b
16 b
15 b
18 ab
19 ab
14 b
29 a
Yield 2
(June 17)
136 ab
130 bc
123 bc
169 a
130 bc
118 c
157 ab
Yield 3
(June 23)
283 a
258 ab
279 a
288 a
244 ab
288 a
198 b
Total
1-3
435 ab
404 ab
417 ab
476 a
393 ab
420 ab
384 b
74
58
69
70
58
64
70
NS
NS
NS
0.01
NS
NS
NS
0.08
NS
NS
F probability fumigation
F probability oxamyl
a
Cull fruits
(No)
Total
Fumigant treatments were applied on March 1; beds were covered with plastic mulch immediately following chisel fumigation;
Oxamyl was applied through the drip tape at planting (March 26) and 2 and 4 weeks afterwards.
Yields are for 10 plants per plot (15 ft bed length); data are means of five replications. Means in the same column followed by the
same letter are not different (P = 0.05) according to Duncan’s multiple range test; no letters indicate non-significant difference; NS =
not significant (P>0.10).
b
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Table 6. Effects of soil fumigation with and without oxamyl drip applications on weight of marketable tomato cv. Amelia,
spring 2004, Black Shank Farm Tifton, GA.
Fumigation a
Rate /
acre
Oxamyl b
Marketable fruits (Lbs)
Cull fruits
(Lbs)
Yield 1
(June 8)
Yield 2
(June 17)
Yield 3
(June 23)
Total
1-3
Total
7 ab
7 ab
7 ab
7 ab
8 ab
6b
12 a
70
69
67
85
71
66
78
130 ab
131 ab
145 a
137 a
126 ab
148 a
100 b
207
207
219
229
205
220
191
333
332
335
332
333
332
334
F probability fumigation
NS
NS
NS
NS
NS
F probability oxamyl
NS
NS
NS
NS
NS
Methyl bromide (67-33)
Methyl bromide (67-33)
Methyl bromide (67-33)
Metam sodium + chloropicrin
Metam sodium + chloropicrin
Metam sodium + chloropicrin
Non-Treated
300 lbs
300 lbs
300 lbs
37.5 G + 100 lbs
37.5 G + 100 lbs
37.5 G + 100 lbs
N/A
No
2 Qts/A
4 Qts/A
No
2 Qts/A
4 Qts/A
No
a
Fumigant treatments were applied on March 1; beds were covered with plastic mulch immediately following chisel fumigation;
Oxamyl was applied through the drip tape at planting (March 26) and 2 and 4 weeks afterwards.
Yields are for 10 plants per plot (15 ft bed length); data are means of five replications. Means in the same column followed by the
same letter are not different (P = 0.05) according to Duncan’s multiple range test; no letters indicate non-significant difference; NS =
not significant (P>0.10).
b
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