HUWPleL R iimeo Report EV-1972-3 April, 1972
JUN 2a$We f s~ Soil Pesticides on Sugar Cane Yields in Florida
H. H. Samol and S. R. Johnson -
I.F.A.S. Univ. of Florida
lireworms and nematodes are common soil pests of sugar cane in Florida.
The economic importance of the wireworm (itelanotus communis) is well known
to all Florida growers that have planted sugar cane without some cultural
or chemical attempt to control this pest (1).
Nematodes have also damaged sugar cane in Florida (3). However, the
amount of damage throughout the industry is not known.
Parathion and Diazinon were the only materials available to the cane
grower for a number of years. Recently, several new materials, which have
different modes of action, different chemical and physical properties, and
a wide variation in cost per acre for treatment have been registered for
either wireworm and/or nematode control in sugar cane.
The purpose of this study was to observe the effect on sugar cane yields
and obtain cost return com rari~on. .for.these materials under similar conditions
in a replicated test. Hopefully the *results would aid the grower in selecting
a material and rate that will give the most profitable returns.
MATERIALS AND METHODS
The test area selected was on Hatton Brothers Farm approximately nine
miles east of Canal Point, Florida. The site was in the east end of a field
that had been in Bahia grass pasture for the previous 6 years. The field had
been mechanically fallowed to reduce grass, weeds, wireworms and nematodes in
preparation for planting.
The test was in a randomized complete block design with 3 replications.
Each plot contained four rows 50-feet long for a total of 200 row feet
Wireworm populations were estimated by counting the number collected
from sweet corn ear baits buried and left in the test area for 11 days before
the chemical treatments were applied. Ten ears were buried randomly at a
depth of 12 inches, and ten ears at 24 inches.
Six composite soil samples were taken prior to planting and treating,
and were analyzed for nematodes.
/Entomologist, Florida Sugar Cane League, Inc., Clewiston, Florida 33440
and Assistant Nematologist, University of Florida, IFAS, Agricultural
Research and Education Center, Belle Glade, Florida 33430.
Materials included in this test were Parathion 10G, Diazinon 14G,
Dyfonate 10G, Dasanit 15G, and Furadan 10G. Parathion, Diazinon and Dyfonate
are registered for use against wireworms. Dasanit is registered for use
against nematodes and Furadan is registered for use against both wireworms
and nematodes. All materials were used at 3 rates and hand applied in a
12 to 15-inch band over the top of the seed cane in the open furrow on
November 4, 1970 and covered the same day. A pint jar with holes punched
in the lid was used to distribute the chemicals. Materials for each row were
pre-weighed in the laboratory and several passes were made over the row
until all the chemical was applied.
All plots were covered using a commercial covering rig which had been
applying Furadan 10G at 40 Ibs per acre. This rig inadvertently covered 2
rows of one plot of each of these treatments with the 40 lbs rate of Furadan
in addition to the test materials already applied: Furadan 30 Ibs, Parathion
20 Ibs, Check, Furadan 20 Ibs and Diazinon 28 ibs.
Stand counts for each plot were made.6 weeks and 6 months after planting.
The juice analysis for each plot was determined from 10 stalks selected at
random and cut on January 24, 1972. The stalks were milled on January 25
and brix and pol were determined by the sugar lab at the Agricultural Research
and Education Center, Belle Glade. All plots were cut and weighed on February
7, 1972. The number of millable stalks per plot was estimated using the
total plot weight and the average stalk weight. Stant counts and juice
analysis were adjusted for the plots that had been overtreated with Furadan
10G at 40 Ibs per acre.
Brix, pol and plot weights were used in estimating the tons of sugar
per acre produced by each treatment (2). Tons of sugar per acre were convert-
ed to standard tons of cane (12.5 percent sucrose per ton) per acre. The
value of standard TCA and chemical costs were used in making a cost-return
RESULTS AND DISCUSSION
Wireworm sampling results. Results of the wireworm sampling are shown
in Table 1. No attempt was made to convert these figures into population
numbers per acre. The authors consider the average of 6.7 wireworms per bait
ear of corn to be of sufficient numbers to cause serious damage to plant cane,
Yields from the check plots support this hypothesis.
Nematode sampling results. The nematode population was found to be very
low in the test area. The spiral nematode (Helicotylenchus sp.), the ring
nematode (Criconemoides sp.) and the stund nematode (Tylenchorhynchus sp.)
were the only plant parasitic nematodes present.
Based on our current knowledge of these nematodes, the populations were
too low to cause serious injury to the young cane plants. The practice of
fallowing the land for a number of months before planting will reduce
nematode populations and was thought to be the contributing factor here.
However, these nematodes can repopulate rapidly and could become a problem
in future stubble crops.
Stand counts and millable stalks per plot. Results of the stand counts
at 6 weeks and 6 months and the estimated millable stalks are shown in Table
II. The most interesting aspect of this data is that plots with high"stand
counts early).had low counts at 6 months and harvest. Diazinon at 28. bs
had the most stalks, at 6 weeks, but ranked 9th at 6 months and 12th at har-
vest. Similarly, all Parathion treatments ranked in the upper one-half of
plots-at 6 weeks, but were in the lower one-half at'6 months and harvest. On
the other hand, all Furadan treatments ranked low at 6 weeks, but ranked 1st,
2nd, and 4th at 6 months and 1st, 2nd, and 3rd at harvest. Dasanit at 23.3
Ibs followed a pattern similar to the Furadan treatments. It ranked 12th
at 6 weeks, but was 3rd at 6 months and 8th at harvest. Dyfonate was fairly
consistent and ranked in the upper one-half throughout the test. The check
plot was poorest in every instance, ranking 16th throughout.
The reason for these differences in early and mid-season stalk counts is
not known. But growers should be aware of this possibility and wait until
yield results are obtained before r:al-ing a decision as to which material is
best suited for their farm operation.
Pounds of sugar per acre. The pounds of sugar per acre estimated from
the plot yields are shown in Table III. Statistically, the check was
significantly lower in yield than all chemical treatments. This clearly
shows the value of soil insecticide treatments when wireworm infestations are
There was not a great deal of statistical difference between the chemical
treatments. The only statistical difference of importance here is the dif-
ference between all Furadan treatments and all Diazinon treatments. Furadan
treatments were also significantly different from two Dasanit treatments, and
one Parathion treatment.
There was no significant difference between rates of a particular
material, however, the high rates of Parathion and Dasanit gave lower yields
than their lower rates. Growers should use caution not to overtreat as the
higher rates of some materials may actually reduce yields as seen in Table III.
Cost-return. Table IV presents a cost-return comparison of all the
treatments tested. The exact price of insecticide granules will vary with
time and among dealers, and the yield from a given treatment in commercial
fields will probably not be the same as the yields from these small plots.
However, the comparisons between different treatments is the item we wish to
The ranking in the cost-return Table IV is similar to that of the
theoretical yield, Table III. Furadan at the 20 Ib rate gave the largest
return in increased yield over the added cost of the granules.
It is interesting to note that the two most commonly used treatments
during the last five years, i.e., Parathion 60 lbs per acre and Diazinon 42
Ibs per acre, are close to the bottom in yield and return.
SL'. I ARY
Results of this test clearly demonstrate the value of a soil pesticide
application at planting time when sugar cane is grown without the benefit
of flooding or some other cultural practice to reduce wireworm populations.
It also points out that some of the newer soil pesticides available can give
a greater return for money invested even though the initial cost may be
greater than with the standard materials.
All treatments in this test were applied in bands about 12 to 15-inches
wide. Banders which could produce this width band are not normally used
on commercial covering rigs but might improve the placement of the granules.
Proper application is just as important as the choice of insecticide.
Data from this test conducted for one year in one location are not
sufficient to provide a basis for recommendations throughout the sugar
industry. However, this information coupled with the observations and
experiences of the individual grower may help him in deciding which chemical
and rate should be used.
1. Gifford, J. R. 1964. A brief review of sugarcane insect research in
Florida. Soil and Crop Sci. Soc. of Fla. Proc. 24: 449-453.
2. Rice, E. R. and L. P. Hebert. 1968. Sugarcane variety tests in Florida,
1967-68 season. Crops Research. ARS 34-103.
3. Winchester, J. A. 1964. Nematodes as a factor in sugarcane varietal
decline in Florida. The Sugar Journal 27 (1): 16-20.
Table I. Number of wireworm larvae C(lelanotus communis) collected from corn
baits buried at two depths and left for 11 days in the plot area.
Table II. Stand counts during'growing season comparedto estimated millable stalk
count at harvest.
indicate ranking of stand counts.
/ Numbers in parenthesis
Number stalks per plot .
December 22, 1970 May 24, 1971
6 weeks 6 months
232 (8) 1/ 745 (2) 1/
204 (13b) 737 (4)
222 (11) 775 (1)
248 (5) 701 (6)
229 (9) 628 (8)
266 (2) 720 (5)
257 (3) 588 (12)
209 (12) 744 (3)
252 (4) 668 (7)
234 (7) 578 (13)
238 (6) 568 (14)
270 (1) 627 (9)
203 (15) 589 (11)
226 (10) 612 (10)
204 (13a) 450 (15)
stalk per plot
February 7, 1972
Table III. Calculated yields of tons of cane per acre, sugar per ton of cane,
and sugar per acre for each treatment.
Rate per acre
Yield of 960 sugar
Per ton Per
of cane acre
1/ eans. followed by same letter are not significantly
of probability, Duncan's Multiple range test.
different at the 5% level
based on standard tons of cane and chemical cost per acre.
Table IV. Cost-return comparisons
Rate per acre
Cost per acre
Standard TCA Gross value TCA--
check ner acre
cost of material
/ Standard sugar cane value of $11.00 per ton.
a Rate neracre cliek )er acr