Response of flowering gladiolus to fluazifop-p-butyl

Material Information

Response of flowering gladiolus to fluazifop-p-butyl
Series Title:
Bradenton GCREC research report
Gilreath, J. P ( James Preston ), 1947-
Gulf Coast Research and Education Center (Bradenton, Fla.)
Place of Publication:
Bradenton Fla.
Gulf Coast Research & Education Center, IFAS, University of Florida
Publication Date:
Physical Description:
2, 2 p. : ; 28 cm.


Subjects / Keywords:
Gladiolus -- Florida ( lcsh )
Herbicides -- Physiological effect -- Florida ( lcsh )
City of Bradenton ( local )
Herbicides ( jstor )
Crops ( jstor )
Tillage ( jstor )
government publication (state, provincial, terriorial, dependent) ( marcgt )
non-fiction ( marcgt )


General Note:
Caption title.
General Note:
"January, 1985"
Statement of Responsibility:
J.P. Gilreath.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
62558409 ( OCLC )


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site maintained by the Florida
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Copyright 2005, Board of Trustees, University
of Florida

Gulf Coast Research & Education Center
/i IFAS, University of Florida
( y .-' 5007 60th Street East
Bradenton, Florida 34203

Bradenton GCREC Research Report BRA1985-2 January 1985


J. P. Gilreath

Postemergence applications of 0.25 and 1.0 lb./acre of PP005
(fluazifop-P-butyl) (butyl (R)-2[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]-
phenoxy] propanoate) were evaluated for crabgrass control, phytotoxicity to
and yield response of 'Manatee Yellow' gladiolus (Gladiolus x hortulanus
L.). Crabgrass control was excellent at both rates. Gladiolus plants were
not injured by 1 or 2 applications of PP005. Two applications of PP005 at both
rates did not affect yield of marketable flower spikes at any harvest date
or season total, indinnting postemergence applications of PP005 for grass
control would be effective and safe in flowering gladiolus.

Weed control in gladiolus is a major production problem, especially on the
light sandy soils of Florida. To control weeds throughout the production
season, herbicides must be applied pre and postemergence to the crop. Up to
4 applications of herbicide are often necessary to control weed populations.
Grass weeds are frequently one of the more numerous weeds in gladiolus
fields. Alachlor and more recently pronamide have been used for weed
control in gladiolus with good results. However, concern about contamination
of ground water and accumulation of herbicide residues in the soil to levels
which might be phytotoxic to subsequent crops encourages the use of post-
emergence foliarly applied herbicides which would result in less herbicide
contacting the soil. Fluazifop-butyl has done an excellent job of controlling
grass weeds with no injury to gladiolus even at rates as high as 1.0 lb./acre
applied 4 times during the season (J.P. Gilreath, unpublished data), but all
of this research was conducted with a racemic mixture of the 2 enantiomers.
Recently, the manufacturer (ICI Americas Inc.) has indicated that in the
future the product may contain only the R or dextrorotatory enantiomer as this
is the enantiomer which is responsible for its herbicidal properties. Since
differences in herbicidal properties of these enantiomers exist, there also
may be differences in crop response. In anticipation of this change in tho
product an experiment was conducted to determine efficacy of crabgraos
control and the response of flowering gladiolus to postemergence applications
of fluazifop-P-butyl,(the R enantiomer).

Materials and Methods
Number 2 size flowering corms of 'Manatee Yellow' gladiolus were planted
February 22, 1984 in raised beds of Eau Gallie fine sand which had been
fumigated with 300 lb./A of a commercial fumigant containing 67% methyl
bromide and 33% chloropicrin. Fumigation was employed to eliminate other
biological factors, so that any yield effects would be due to the chemical
itself. Ten grams of crabgrass (Digitaria ciliaris) seed were uniformly
sprinkled over each herbicide treated plot and lightly incorporated with a

rake immediately after planting the gladiolus corms. Since other research
indicated the herbicide would control grass weeds, the untreated control
plots were not seeded with crabgrass in order to determine if the herbicide
reduced yields. Crabgrass was also planted in plots unplanted to gladiolus
which were adjacent to the crop area. These plots were used to ascertain the
germination capability of the seed employed in the test. Crop nutrition was
supplied by applications of a commercial 6-6-6 fertilizer to provide a total
of 151, 74,and 140 lbs./acre N,P,and K, respectively. Plot size was 25 feet
of row on a 4.5 feet row spacing with approximately 3.5 corms per row foot.
Treatments were replicated 4 times and assigned to plots in a randomized
complete block design. Treatments were an untreated control treatment, 0.25
lb./acre PP005 and 1.0 lb./acre PP005, with the herbicide treatments applied
twice during the season on March 23 and April 19, 1984. All applications
were made with a CO2 back pack sprayer operated at 3 mph and 21 psi pressure
with 2 unijet.nozzles delivering 26.6 gal/acre. Plots were maintained free
of undesired weeds for the duration of the experiment by hand weeding.

Crop plant vigor (inverse of phytotoxicity) was evaluated on April 6,
1984 after 1 application of the treatments. Crabgrass control was evaluated
twice: April 4 and May 8, 1984. Gladiolus bloom spikes were harvested 5
times at 3 to 4 day intervals. Data were analyzed by analysis of variance
and treatment means were ranked by Duncan's new multiple range test at the
5% level of significance.

Results and Discussion

Gladiolus plant vigor was not reduced by 1 application of any of the
treatments (Table 1). Crabgrass control was excellent with both rates of the
herbicide with no differences observed between rates at either date (Table
1). There were no differences in production of marketable bloom spikes at
any harvest date (data not presented) or for the season total (Table 2). The
data indicate that PP005 is both effective and safe for use for postemergence
control of crabgrass in flowering gladiolus. This will provide the gladiolus
grower with a means of controlling emerged grasses, while reducing his
dependence on soil applied herbicides which might ultimately cause a
buildup of potentially phytotoxic residues in the soil and ground water


The author wishes to offer his sincere appreciation to Manatee Fruit
Company for donating the corms used in this experiment and for growing the
crop in numerous previous experiments which ultimately led to this
experiment. In addition, appreciation is extended to ICI Americas, Inc. for
support of this and previous research on cut flowers.

Table 1. Effect of PP005 on vigor of 'Manatee Yellow' gladiolus plants and
crabgrass control. Bradenton, FL. 1984.

Crabgrass Control
Rate Vigor RatingY Ratingx
Treatments (lb. a.i./Acre) (April 6) April 6 May 8

Untreated check --10.Oa 10.0a 10.Oa

PP005 0.25 9.9a 10.Oa 10.Oa

PP005 1.00 10.Oa 10.Oa 10.Oa

ZApplication of PP005 included X-77 non-ionic surfactant at a rate of 0.25%
by volume.

YVigor was evaluated on a 0 to 10 scale, where 0 indicates all plants were
dead, and 10 represents no phytotoxicity.

XCrabgrass control was evaluated on a 0 to 10 scale, where 0 indicates no
control, andl10 represents 100% control. Although the untreated control was
not seeded with crabgrass, an adjacent unplanted area was in order to
.ascertain the germination capability of the crabgrass seed.

wTreatment means within a column followed by the same letter are not
significantly different at the 5% level as determined by Duncan's new
multiple range test.

- >*

Table 2. Effect of two applications of PP005 on 'Manatee Yellow' gladiolus
bloom spike production--season total. Bradenton, FL. May, 1984.

Treatment i (lb. a.i./A) Number Weight (lbs.)

Untreated check 73aY 18.4a

PP005 0.25 78a 17.4a

PP005 1.00 74a 16.7a

ZApplications of PP005 included X-77 non-ionic surfactant at a rate of 0.25%
by volume.

YTreatment means within a column followed by the same letter are not
significantly different at the 5% level as determined by Duncan's new
multiple range test.