NORTH FLORIDA EXPERIMENT STATION
S ArS S- f-l Quincy, Florida
January 6, 1969
NFES Mimeo Report 69-1 1 ,
CHEMICAL CONTROL OF NEMATODE ROOT ROT COM EX OF SHADE-GROWN TOBACCO
W. B. Tappan- MAR 7 1
OBJECTIVE !( ,IrU
To evaluate the effectiveness of chemical soil treatments in ?7e"c6ntroblbof nematode
root rot complex of shade-grown tobacco.
MATERIALS AND EQUIPMENT
Test Materials.--Materials, chemical composition, formulations, and sources are
presented in Table 1.
Equipment.--A gravity flow single-shank injector devised by the North Florida Experiment
Station was used to inject SD-14647. An FU-30-Series John Blue applicator with F-500-U pump
equipped with manifold and flow regulator was used to inject D-D and Vorlex. Ground seals
after treatment were made with a crosstie drag. A sprinkling can was used to make appli-
cations of TH-285N and TH-336N. All non-injected treatments were incorporated into the soil
after application with a rotary tiller.
METHODS AND PROCEDURE
Experimental Design.--Eleven treatments and an untreated check were replicated four
times in randomized complete blocks. Plots were approximately 0.0118 acre in size, and
were located in the west half of the "bug" shade. Each plot was 36 feet long and 16 feet
(four rows) wide. The two inside rows reduced to 32 feet in length constituted the
experimental plot from which data were taken. The two outside rows acted as buffers
between plots. Alleys between blocks of plots and buffer zones within blocks were 6 and 8
feet wide, respectively.
Treatments.--All plots were fertilized with 19.4 tons per acre of stable manure on
December 2, 1966, and 1,000 pounds per acre of high calcic lime on December 7. Treatments
were applied on February 1, 16 and March 9, 1967. On those dates, soil temperatures at the
4-inch level were 630F. at 4 P. M., 540 at 9 A. M., 650 at 1 P. M., respectively. Rainfall
and irrigation totalled 21.1 inches from February 1 to completion of crop harvest on June 21.
The plot area was treated with 10% heptachlor and 14% diazinon granules at 60 and 20
pounds per acre, respectively, on February 27 for cutworm and wireworm control.
Methods of application of the test materials were as follows: Dasanit, Furadan, Mocap,
and Temik granules were broadcast on the soil surface and rotary-tilled to a depth of 6 to
8 inches; TH-285N and TH-336N were mixed with water, broadcast on the soil surface, and
rotary tilled to a depth of 6 to 8 inches; D-D and Vorlex were injected on 8-inch centers;
and SD-14647 was diluted 1:1 in a petroleum solvent and injected on 12-inch centers. All
injected materials were applied to depths of 6 to 8 inches and sealed with a drag immediately
following broadcasting of a 7-6-9 fertilizer at 2,000 pounds per acre on March 9. Rows were
prepared for transplanting on March 20, and two sidedressings of fertilizer at 500 pounds
per acre each were applied on April 7 and April 10. Florida 15 variety of shade-grown
tobacco was transplanted in all plots on March 20. On April 4, vacancies in each row were
reset with plants from the treated ends of each plot row.
Associate Entomologist, North Florida Experiment Station, Quincy.
Associate Entomologist, North Florida Experiment Station, Quincy.
Weed Growth.--Weed growth was rated visually on April 5, 18, 25, and May 9 according to
over-all density of growth per plot. The rating system was as follows:
0 No weed growth
1 Light weed growth
2 Moderate weed growth
3 Heavy weed growth
4 Very heavy weed growth
The weed index is reported for April 5, 18, and May 9.
Plant Growth.--Measurements of plant growth were made on April 18, 25, May 2 and 9,
after plants began showing wilting and stunting symptoms. Plant growth as an indication of
response to the various treatments was reported as a measurement in inches per plant from
the base of the stalk at ground level to the base of the terminal bud. Height measurements
were discontinued as soon as the plants began to button. Plant growth responses are
somewhat accelerated after formation of the reproductive portion, and this tends to confuse
height measurements.
Nematode Populations.--Root and soil samples were taken from the 5th, 15th, and 25th
plants from the east buffer row of each plot on June 26. The three root and soil samples
were combined into one composite sample for each plot. The samples were processed and the
results were reported as number of nematodes per gram of root or per 100 cubic centimeters
of soil.
Root Disease Readings.--Root disease readings were taken from every 3rd plant in the
experimental plot rows on June 28, constituting 10 plants per row or a total of 20 plants
per plot. Diseases rated in these observations were black shank, root knot, and coarse
root (nematode root rot). The severity of each disease was rated in eleven categories
ranging from 0 to 100. The readings were reported as the disease index.
Phvtotoxicitv Readings.--Phytotoxicity readings were taken on April 13, 20, 27, May 2,
8, 16, 23, 30, June 6 and 13. The readings were based upon foliage symptoms and stunting
as follows:
0 No phytotoxicity
1 Slight leaf curl and chlorosis or stunting
2 Moderate leaf curl and chlorosis or stunting
3 Heavy leaf curl and chlorosis or stunting with
some leaf necrosis
4 Severe chlorosis and necrosis or stunting with leaf curl
The phytotoxicity index is given for April 13, 20, 27, May 2, 8, 16, 23, 30, and June 13.
Crop Evaluation.--The crop was harvested (primed), cured, fermented, and graded
according to the usual commercial practices. Seven primings were made during the crop
season on May 10 (3 leaves), May 19 (3 leaves), May 29 (4 leaves), June 5 (3 leaves),
June 8 (3 leaves), June 15 (3 leaves), and June 21 (3 to 5 leaves). The leaves taken at
each priming represent the number primed per stalk. Yield was calculated in pounds per acre
from the total weight of fermented leaves from each treatment replication. A sample (two
hands totaling 64 to 76 leaves; approximately 220 grams) of leaves from each priming of
each replication was graded to obtain the grade index. The best grade was assigned a factor
of 1.000, and the other grades were assigned proportionately smaller factors according to
their relative market value. Crop index was obtained by multiplying the yields in pounds
per acre by the grade index. The crop index is a measure of the total value of the crop.
The fire-holding capacity was determined by measuring the length of time in seconds that the
leaf burned after being ignited by an electric cigarette lighter. Five leaves of the 2nd,
4th, and 6th primings from each replication were tested by burning near the middle of a tip
quarter and a base quarter of each leaf. The mean of 120 readings were reported as the
index. The weight of the crop in off-color, medium wrapper, broke, spotted wrapper, good
stain, bad stain, and No. 1 string wrapper was calculated in percent.
RESULTS AND DISCUSSION
Weed growth (Table 2) was reduced most effectively by the high rate of Vorlex.
Plant growth in the check indicated that the Florida 15 variety possesses a tolerance
to attack by nematodes; namely, Pratylenchus, Rotylenchulus and Helicotylenchus spp.
Statistical analysis of plant growth showed none of the treatments were significantly
better than the check. Both rates of Mocap reduced plant growth, which reflected the
phytotoxic effect on the root system.
Counts of Pratylenchus spp. in the roots were variable. All treatments except Vorlex
at the low rate reduced the number of Pratylenchus spp. in the roots.
Temik and Mocap at the high rate effectively reduced the number of Pratylenchus spp.
in the soil, while none of the treatments were particularly effective in reducing
Rotylenchulus spp. numbers in the soil. All of the treatments with the exception of
TH-336N effectively reduced the number of Helicotylenchus spp. in the soil.
Black shank was lowest in plots treated with TH-336N, however, the low incidence of
black shank can be attributed to the resistance of the variety. Root knot, as has been the
case for the past several years, was not evident in any plot. Coarse root was best
controlled with SD-14647.
Listed in order of descending yields (Table 2): Vorlex at the low rate, Temik,
TH-336N, SD-14647, and Vorlex at the high rate gave best results. Reduced yields with
several of the treatments were probably due to root phytotoxicity, but in the case of
Furadan, most of the loss resulted from foliage injury.
Treatment with Mocap at the low rate resulted in the best grade of tobacco, while
TH-336N gave the best crop index. The high percentage of No. 1 string wrapper produced
by the low rate of Mocap was directly responsible for the high grade index value. None of
the treatments adversely affected the fire-holding capacity of the crop, but Furadan was
the best treatment. Temik and the low rate of Mocap were the best treatments from the
standpoint of overall improvement of yield and crop value.
Mocap at both rates caused a moderate amount of phytotoxicity, which was apparent from
growth measurement and through visual observation (Table 2). Stunting from the high rate
of Mocap was more evident as the season progressed, whereas plants treated with the low
rate were beginning to recover near the season's end. Stunting was also evident on plots
treated with TH-285N, Dasanit, Temik, D-D, Vorlex, and TH-336N. Stunting from TH-285N and
Mocap was severe enough to be of concern. Furadan caused considerable foliage phytotoxicity
in early season, which began disappearing near the end of the season. Phytotoxicity from
Furadan was characterized by chlorotic and necrotic spotting of the lamina, and upward
curling of leaf edges and tips. The injury caused by Furadan did not appreciably affect
the crop except where necrosis appeared, which caused a slight reduction in yield. Leaves
treated with Furadan and having chlorotic lesions in the field could not be differentiated
from normal leaves in the packinghouse grading process. However, the Furadan treatment
caused the highest percentage of off-colored tobacco, but this was not statistically
different from the check.
Linear correlations (Table 3) showed that plant height had an adverse effect on quality
of the crop and the number of broken leaves. The relationship between yield and
-4-
Pratylenchus spp. in the roots and soil indicated that the nematodes were related to an
increase in yield. This same trend was noted with respect to the relationship between
Pratylenchus spp. and plant growth. Black shank apparently was aggravated by coarse root,
as there was a significant positive correlation between the two factors. The fire-holding
capacity of spotted wrappers was reduced, while off-colored leaves retained the fire for a
longer period.
Florida 15 was not affected as much by nematodes in the roots and soil as other
varieties have been in prior tests. This may be due partially to tolerance of the variety
to nematode attack. However, the evidence indicates that nematodes may stimulate growth of
Florida 15. In any event, grade and crop value of the variety was not adversely affected
by nematodes in this experiment.
WBT
25 CC
1/6/69
NORTH FLORIDA EXPERIMENT STATION
Quincy, Florida
Table 1.--Materials, Compositions, Formulations, and Sources of Materials Used for Control of Nematode Root Rot Complex-1967.
Material Chemical Composition Formulation Source
Dasanit 0,0-diethyl 0-(p-(methylsulfinyl) phenyl] phosphorothioate
D-D 1,3-dichloropropene and 1,2-dichloropropane
Furadan 2,3-dihydro-2,2-dimethyl 7-benzofuranyl N-methylcarbamate
Mocap 0, ethyl S,S-dipropyl phosphorodithioate
SD-14647 D-D + methanesulfonic acid, 2,4-dichlorophenyl ester
Temik 2-methyl-2-(methylthio) propionaldehyde 0-(methylcarbamoyl) oxime
TH-285N 4-chloropyridine-N-oxide
TH-336N 4-chloropyridine hydrochloride
10% granules
100% liquid
5% granules
10% granules
100% liquid
10% granules
90% water soluble
powder
90% water soluble
powder
100% liquid
Chemagro Corp.
Shell Chemical Co.
Niagara Chemical Div.
Mobil Chemical Co.
Shell Development Co.
Union Carbide Corp.
Thompson-Hayward Chem. Co.
Thompson-Hayward Chem...Co.
Vorlex D-D + methyl isothiocyanate
- --
Morton Chemical Co.
NORTH FLORIDA EXPERIMENT STATION
Quincy, Florida
Table 2.--Effects of Nematocidal and Fungicidal Treatments on
Reduction of Nematodes, Reduction of Root Diseases,
on Florida 15 Shade Tobacco 1967.
Weed Growth, Plant Growth, "
Crop Data, and Phytotoxicity
Weed Index Plant Heights Inches
Treatment and Dates of Avg. 4 Reps. Avg./Plant 4 Reps.
Rate per Acre Treatment 4/5 4/18 5/9 4/18 4/25 5/2 5/9
Temik, 10 G, 150 Ibs. Mar. 9 2.50 3.50 4.00 11.81 22.33 33.86 51.35
Mocap, 10 G, 150 Ibs. Mar. 9 2.50 2.75 3.75 11.51 20.99 30.60 47.89
Mocap, 10 G, 300 Ibs. Mar. 9 2.50 3.50 4.00 11.98 21.83 32.09 49.28
SD-14647, 10 gals. Feb. 1 2.25 4.00 4.00 14.58 26.44 36.94 54.49
TH-285N, 90 WSP, 11.1 Ibs. Mar. 9 2.50 3.50 4.00 14.24 25.09 35.68 53.06
TH-336N, 90 WSP, 11.1 lbs. Mar. 9 2.50 3.50 4.00 14.14 25.20 36.04 53.83
Vorlex, 7 gals. Feb. 16 3.50 4.00 4.00 14.74 27.05 38.28 56.66
Vorlex, 20 gals. Feb. 16 2.00 3.25 3.00 14.33 26.00 37.85 56.59
D-D, 20 gals. Feb. 16 2.50 3.50 4.00 13.28 24.80 35.49 53.35
Dasanit, 10 G, 250 lbs. Mar. 9 2.00 4.00 4.00 13.91 24.53 35.52 52.68
Furadan, 5 G, 300 lbs. Feb. 1 2.00 3.50 4.00 14.75 26.83 38.73 56.18
Check, untreated ------- 3.50 4.00 4.00 15.49 27.75 38.91 56.78
L.S.D. 5% 0.75 0.60 0.20 3.34 5.07 6.08 6.88
L.S.D- 1% 1.01 0.81 0.27 4.49 6.81 8.18 9.26
C.V. (%) 21 11 4 17 14 12 9
NORTH FLORIDA EXPERIMENT STATION
Quincy, Florida
Table 2: Continued.
Per gram of root Per 100 cc. of soil
Treatment and Dates of Pratylenchus spp. Pratylenchus spp. Rotylenchulus spp. Helicotylenchus spp.
Rate per Acre Treatment 6/26 6/26 6/26 6/26
Temik, 10 G, 150 lbs. Mar. 9 0.15 0.00 0.75 0.00
Mocap, 10 G, 150 lbs. Mar. 9 1.65 13.00 4.25 27.75
Mocap, 10 G, 300 Ibs. Mar. 9 1.13 3.25 0.00 9.50
SD-14647, 10 gals. Feb. 1 10.93 19.00 6.00 60.00
TH-285N, 90 WSP, 11.1 lbs. Mar. 9 16.53 48.75 79.50 72.25
TH-336N, 90 WSP, 11.1 lbs. Mar. 9 15.00 34.75 353.25 119.75
Vorlex, 7 gals. Feb. 16 40.68 45.25 20.75 39.25
Vorlex, 20 gals. Feb. 16 8.65 15.50 10.25 6.75
D-D, 20 gals. Feb. 16 11.00 16.50 5.75 18.25
Dasanit, 10 G, 250 Ibs. Mar. 9 1.30 9.25 17.25 30.25
Furadan, 5 G, 300 Ibs. Feb. 1 1.55 11.00 0.75 0.00
Check, untreated ----- 16.45 34.50 91.75 166.00
L.S.D. 5% 19.88 28.24 217.72 63.17
L.S.D. 1% 26.74 37.97 292.79 84.96
C.V. (%) 133 94 308 96
NORTH FLORIDA EXPERIMENT STATION
Quincy, Florida
Table 2: Continued.
Fire-
Disease Index 6/28-Avg. 4 Reps. Grade Crop Holding
Treatment and Dates of Black Root Coarse Yield Index Index Capacity
Rate per Acre Treatment Shank Knot Root Avg. 4 Reps.
Temik, 10 G, 150 Ibs. Mar. 9 3.50 0.00 46.25 2302 0.778 1789 5.7
Mocap, 10 G, 150 Ibs. Mar. 9 3.00 0.00 44.75 2150 .793 1706 5.5
Mocap, 10 G, 300 lbs. Mar. 9 5.75 0.00 55.75 2125 .786 1669 4.9
SD-14647, 10 gals. Feb. 1 2.50 0.00 36.40 2260 .776 1752 5.5
TH-285N, 90 WSP, 11.1 lbs. Mar. 9 3.75 0.00 42.75 2186 .729 1595 5.4
TH-336N, 90 WSP, 11.1 lbs. Mar. 9 1.50 0.00 41.25 2267 .776 1796 5.1
Vorlex, 7 gals. Feb. 16 2.75 0.00 45.75 2304 .776 1788 5.6
Vorlex, 20 gals. Feb. 16 2.00 0.00 41.50 2222 .740 1647 4.9
D-D, 20 gals. Feb. 16 2.50 0.00 42.50 2186 .751 1644 4.3
Dasanit, 10 G, 250 lbs. Mar. 9 3.25 0.00 42.50 2188 .754 1650 5.3
Furadan, 5 G, 300 lbs. Feb. 1 2.75 0.00 46.75 2138 .756 1618 6.5
Check, untreated ------ 4.75 0.00 46.75 2290 .735 1686 5.7
L.S.D. 5% 3.37 ---- 6.66 111 .066 175 2.0
L.S.D. 1% 4.53 ---- 8.96 149 .088 235 2.6
C.Vr (%) 74 ---- 11 4 6 7 25
NORTH FLORIDA EXPERIMENT STATION
Quincy, Florida
Table 2: Continued.
Percent Percent Percent Percent Percent
Percent Medium Percent Spotted Good Bad No. 1 String
Treatment and Dates of Off-Color Wrapper Brokes Wrapper Stain Stain Wrapper
Rate per Acre Treatment Avg. 4 Reps.
Temik, 10 G, 150 lbs. Mar. 9 4.0 8.5 12.3 11.2 0.6 0.9 59.7
Mocap, 10 G, 150 lbs. Mar. 9 4.7 14.3 9.4 6.4 0.6 1.3 61.5
Mocap, 10 G, 300 lbs. Mar. 9 4.1 9.0 9.6 12.1 0.8 1.1 60.8
SD-14647, 10 gals. Feb. 1 5.9 11.4 14.9 6.6 0.5 0.7 58.6
TH-285N, 90 WSP, 11.1 lbs. Mar. 9 7.1 16.3 12.4 11.1 0.7 0.9 48.9
TH-336N, 90 WSP, 11.1 lbs. Mar. 9 5.5 11i5 11.3 10.3 0.9 1.5 57.8
Vorlex, 7 gals. Feb. 16 3.0 11.7 12.7 7.5 0.6 1.5 59.7
Vorlex, 20 gals. Feb. 16 4.7 7.2 16.5 10.3 0.2 2.4 54.2
D-D, 20 gals. Feb. 16 3.7 9.8 12.6 13.5 0.2 2.9 54.8
Dasanit, 10 G, 250 Ibs. Mar. 9 7.2 10.2 12.9 11.9 0.7 1.6 53.8
Furadan, 5 G, 300 lbs. Feb. 1 8.7 4.7 15.5 9.2 0.9 1.3 56.1
Check, untreated ----- 6.7 14.8 13.9 7.5 1.4 0.6 51.2
L.S.D. 5% 5.1 6.7 3.5 6.2 1.1 2.1 11.7
L.S.D. 1% 6.9 9.0 4.7 8.3 1.5 2.9 15.7
C.V. (%) 66 43 19 44 117 107 14
NORTH FLORIDA EXPERIMENT STATION
Quincy, Florida
Table 2: Continued.
Treatment and Dates of Phytotoxicity Index Avg. 4 Reps.
Rate per Acre Treatment 4/13 4/20 4/27 5/2 5/8 5/16 5/23 5/30 6/13
Temik, 10 G, 150 lbs. Mar. 9 0.0 0.0 0.0 0.0 1.8 0.5 0.5 0.5 0.0
Mocap, 10 G, 150 lbs. Mar. 9 1.0 1.8 1.5 0.8 2.3 2.3 2.3 2.3 1.3
Mocap, 10 G, 300 Ibs. Mar. 9 1.5 2.5 1.0 1.0 2.3 2.3 2.3 3.3 3.3
SD-14647, 10 gals. Feb. 1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
TH-285N, 90 WSP, 11.1 lbs. Mar. 9 0.0 0.0 0.0 0.0 2.0 2.0 2.3 2.3 1.5
TH-336N, 90 WSP, 11.1 Ibs. Mar. 9 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.0 0.0
Vorlex, 7 gals. Feb. 16 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0
Vorlex, 20 gals. Feb. 16 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0
D-D, 20 gals. Feb. 16 0.0 0.0 0.0 0.0 1.3 1.3 1.0 1.0 1.0
Dasanit, 10 G, 250 lbs. Mar. 9 0.0 0.0 0.0 0.0 1.0 2.0 2.0 2.0 1.0
Furadan, 5 G, 300 lbs. Feb. 1 2.8 3.8 3.8 3.8 3.8 2.8 1.0 0.0 0.0
Check, untreated ----- 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
NORTH FLORIDA EXPERIMENT STATION
Quincy, Florida
Table 3.--Linear Correlations Relating to Soil Nematocide and Fungicide Studies on Shade-Grown Tobacco 1967.
Black Coarse
Weed Plant Praty. Praty. Shank Root
Index Height Roots Soil Index Index Grade Crop
5/9 5/9 6/26 6/26 6/28 6/28 Yield Index Index
Weed Index, 5/9 -.21 .07 .14 .33 .20 .05 .25 .20
Plant Height, 5/9 -.21 .56 .47 -.33 -.34 .48 -.59 -.04
Pratylenchus Roots, 6/26 .07 .56 .84 -.19 -.17 .57 -.14 .33
Pratylenchus Soil, 6/26 .14 .47 .84 -.15 -.28 .39 -.39 .03
Black Shank Index, 6/28 .33 -.33 -.19 -.15 .78 -.25 -.02 -.21
Coarse Root Index, 6/28 .20 -.34 -.17 -.28 .78 -.35 .24 -.11
Yield .05 .48 .57 .39 -.25 -.35 -.03 .73
Grade Index .25 -.59 -.14 -.39 -.02 .24 -.03 .67
Crop Index .20 -.04 .33 .03 -.21 -.11 .73 .67
Fire-Holding Capacity .25 .24 -.02 .04 .08 .09 .11 .04 .11
No. 1 String Wrapper .10 -.48 -.12 -.46 -.06 .28 -.01 .97 .66
Brokes -.44 .83 .11 .06 -.37 -.47 .25 -.59 -.21
Medium Wrapper .27 -.19 .39 .65 .21 -.17 .22 -.13 .07
Off-Color .16 .26 -.31 .07 .04 -.17 -.29 -.48 -.55
Spotted Wrapper .01 -.19. -.32 -.29 .12 .22 -.31 -.27 -.41
Significance of r at 5% level .58
Significance of r at 1% level .71
NORTH FLORIDA EXPERIMENT STATION
Quincy, Florida
Table 3: continued.
Fire No. 1
Holding String Medium Spotted
Capacity Wrapper Brokes Wrapper Off-Color Wrapper
Weed Index, 5/9 .25 .10 -.44 .27 .16 .01
Plant Height, 5/9 .24 -.48 .83 -.19 .26 -.19
Pratylenchus Roots, 6/26 -.02 -.12 .11 .39 -.31 -.32
Pratylenchus Soil, 6/26 .04 -.46 .06 .65 .07 -.29
Black Shank Index, 6/28 .08 -.06 -.37 .21 .04 .12
Coarse Root Index, 6/28 .09 .28 -.47 -.17 -.17 .22
Yield .11 -.01 .25 .22 -.29 -.31
Grade Index .04 .97 -.59 -.13 -.48 -.27
Crop Index .11 .66 -.21 .07 -.55 -.41
Fire-Holding Capacity .04 .27 -.10- .57 -.57
No. 1 String Wrapper .04 -.45 -.29 -.56 -.26
Brokes .27 -.45 -.41 .39 -.12
Medium Wrapper -.10 -.29 -.41 -.02 -.33
Off-Color .57 -.56 .39 -.02 -.10
Spotted Wrapper -.57 -.26 -.12 -.33 .10
Significance of r at 5% level .58
Significance of r at 1% le e! .71
|