'ESTICIDE EVALUATIONS IN SUPPORT OF REGISTRATIONS ON TROPICAL FOLIAGE PLANTS
JUNE 1981 JUNE 1982
IJME L RAR A. R. Chase and L. S. Osborne
University of Florida, IFAS
Agricultural Research Center-Apopka
,1i9 ARC-A Research Report, RH-82-18
S. oUnvOf Florida
if.i oda o annual research report on pesticide evaluations
)nducted at the Agricultural Research Center-Apopka. As in the past, this
?port briefly relates the pesticides tested, the manner in which they were
!sted, and salient results of that experimentation. This is an extremely
1portant portion of the research conducted by University personnel since it is
!cessary toward developing labels for new pesticides and expanding those of
!gistered pesticides. Without the cooperation of University personnel, this
process would slow dramatically. In certain minor crops, such as foliage
plants, this process would be especially hampered since most chemical companies
Snot actively pursue labels for ornamentals due to the relatively small
irket and high liability. These tests also benefit growers by identifying
plants sensitive to certain pesticides which may be labeled inaccurately. In
edition, since pesticide labels rarely contain all of the plants which are
'oduced, this information may aid producers in choosing the safest pesticides
)r their crops.
Fungicide trials performed during 1981-1982 were concerned with both
;tablished and experimental compounds. In each case, fungicides were tested
sing recommended rates and intervals, and on plants which are known to be
isceptible to pathogens that the fungicide could control. Experimental compounds
re tested in several cases to determine phytotoxicity and efficacy in new uses.
ie importance of reducing residues on plant foliage has been recognized by
!veral chemical companies and attempts to reduce them by altering the formulation
: the fungicide have been made. Many additional fungicide efficacy trials were
)nducted during this period which are reported under different research reports
kRC-A RH-81-15 and RH-82-10) or will be available at a later date. Tests
A. Zyban 75 WP
1. Objective Determine the efficacy of Zyban compared to two fungicides
representing its component chemicals (active ingredients) in control
of Fusarium leafspot of Dracaena marginata.
2. Need Investigations of the efficacy of a newly registered compound.
3. Methods All plants were inoculated with the pathogen or water. As
soon as symptoms of Fusarium leafspot appeared, chemical treatments
were initiated: 1. inoculated, water sprays, 2. noninoculated, water
sprays, 3. inoculated, Fungo 50 WP at 0.5 lb/100 gal, 4. inoculated,
Manzate 200 at 1.5 lb/100 gal, 5. inoculated, Zyban at 1.5 lb/100 gal.
Sprays were applied once a week for 7 weeks and plants were watered
4. Results Zyban and Manzate provided superior control when compared to
B. Ornalin 50 WP
1. Objective Determine the potential for control of Rhizoctonia aerial
blight of Hedera helix with Ornalin 50 WP.
2. Need Broaden the list of plants and pests on the Ornalin label.
3. Methods Ivy plants were inoculated with Rhizoctonia solani prior to
application of the following treatments at weekly intervals: 1. Ornali
at 0.5 lb/l0 gal, 2. Ornalin at 0.5 and Fungo 50 at 0.5 lb/100 gal,
3. Ornalin at 1.0 lb/100 gal, 4. Ornalin at 1.0 and Fungo 50 at 0.5 lb/
100 gal, and 5. Fungo at 0.5 lb/100 gal with appropriate control treat-
ments. A total of eight applications were made of the pesticide.
4. Results Both compounds were efficaceous in controlling aerial blight
of ivy. There was no apparent benefit in increasing the rate of the
Ornalin used or combining the two chemicals.
C. Combination Study
1. Objective Determine the safety of using a combination of three pesti-
cides on three foliage plants.
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aedorea elegans (Parlor palm), and Epipremnum aureum (pothos) for
a total of six applications.
4. Results These compounds were safe on both pothos and parlor palm
but Daconil and Vydate caused tipburn and leaf deformity of
schefflera. Although this combination appears safe for use on these
plants under these conditions, it was not unusual to find phyto-
toxicity resulting from the use of two of the three chemicals separal
but not when used together. It must be recommended that combinations
of products be treated carefully and tested under each grower's
D. Daconil 4.17 F
1. Objective Provide information necessary toward expansion of the
number of plants currently on the label.
2. Need The label does not contain as wide a list of plants as is
3. Methods This study was divided into two sets of tests, the first
consisting of efficacy trials for control of palm leafspot, and the
second involving phytotoxicity testing on five other species of
a. Efficacy Daconil was applied to foliage of Chrysalidocarpus
lutescens and Chamaedorea elegans previously infected with Bipoll
(Helminthosporium) setariae. Treatments consisted of a control,
and Daconil applied at 1.04, 2.08, and 4.16 Ib (ai)/100 gal. Treat-
ments were applied twice a month for a total of eight application
Disease severity was rated at the end of the experiment as well
as at the halfway point. Plants were watered by sprinkler irrigat
b. Phytotoxicity Daconil was applied at the rates and timing
described above to the following foliage plants: Dieffenbachia
maculata 'Perfection', Sansevieria trifasciata, Codiaeum sp. (cr(
ton), Epipremnum aureum (pothos), and Aphelandra squarrosa (Zebri
4. Results -
a. Disease control was significant at an early rating for the 4.16
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of treated plants. The possibility that the 25EC formulation would
leave a less unsightly residue was evaluated.
. Methods Rovral 50 WP and 25 EC were used at 0.5 and 2.0 lb/100 gal
every two weeks for a total of eight applications to the following
plants: Aeschynanthus pulcher (lipstick vine), Brassaia actinophylla
(schefflera), Dieffenbachia maculata 'Perfection', and Ficus benjamin
. Results All Rovral treatments resulted in stunting of the schefflei
All of the rates and combinations ofcopper MF-658 and Zyban were
safe for use on philodendron and pothos in these studies.
Insecticide, Miticide, and Nematicide Evaluations
The pesticide tests carried out during this 1981-1982 period concentrated
on obtaining data for label expansion of presently employed chemicals as well as
to establish labels on new chemicals. The major portion of these evaluations
were in the area of phytotoxicity but with efficacy testing against major pests
for which control data was lacking.
Chemicals were selected for evaluations only if judged by this laboratory
to fulfill a need that is presently not being met and also, only if the chemical
producer is serious in efforts for registration in the ornamental tropical
foliage plant industry.
I. Studies with Established Compounds
A. Safer's Agro Chem Insecticidal Soap
1. Objective Determine the efficacy of this soap compared to
Pentac 50 WP for the control of two-spotted spider mite on plants
grown in the interior environment.
2. Need Interiorscapers have a need for a safe effective material to
3. Methods Brassaia actinophylla (schefflera) were grown in
interior rooms and infested with spider mites. The following
treatments were included: a) sprayed to runoff with Soap (4 oz/
gal H20), b) sprayed to runoff with Pentac 50 WP (0.25 lb ai/100
gal H20), and c) control (water only). Pre-treatment and post-
treatment counts were made of the motile stages of the mites. Two
applications of Soap were made.
4. Results Safer's Agro Chem Insecticidal Soap was as effective
at controlling mites as Pentac 50 WP.
B. Vydate 2L, Dycarb, and SD-52618
1. Objective Determine the relative effectiveness of Vydate 2L,
Dycarb, and SD-52618 (Experimental) for the control of
2. Need Substantiation of efficacy claims for newly registered
3. Methods Codiaeum sp. were infested with 5 adult striped
mealybugs (Ferrisia virgata) per plant. The experiment consisted
of the following treatments: 1) SD-52618 (1.33 g/1.89 1),
2) Vydate 2L (4.7 ml/1.89 1), 3) control (water spray), and 4)
Dycarb (4.25 g/1.89 1). Four plants per treatment were sprayed
to runoff. This experiment was repeated.
4. Results In Experiment 1 there were fewer mealybugs per plant
than in Experiment 2. In this experiment Dycarb and Vydate 2L were
not significantly different in their ability to control this
mealybug (100% mortality was achieved with either one). SD-52618
was significantly different than all other treatments in that
it reduced the mealybug population by only 50%. Mealybugs which
survived were protected between two leaves and thus did not
come in direct contact with the pesticide.
In Experiment 2, the mealybugs on only one leaf per plant were
counted before treatment. All chemical treatments reduced the
populations on the test leaf by 100%. After treatment, the
mealybugs on the entire plant were counted. There were some live
mealybugs on the SD-52618, Vydate 2L, and control treatments,
but none on the Dycarb treated plants.
C. Vydate 10G
1. Objective Determine this formulation's ability to control striped
2. Need Investigate efficacy of this newly registered formulation.
3. Methods Codiaeum variegatum were infested with 3 adult mealybugs
per plant. Each plant was grown in a 4" plastic pot. Vydate 1OG
(0.09 g/pot) was added to the soil surface and watered in. Two
weeks after treatment all plants were examined for mealybugs.
4. Results This material retarded population development of this
mealybug but did not give acceptable control.
D. Orthene 75S and Orthene 5% G
1. Objective Evaluated Orthene 75S and Orthene 5% G bait for
phytotoxicity when applied to the soil surface.
2. Need We need to know if this systemic material can be safely
applied to the soil.
3. Methods The granular formulation was applied at two rates
(2 lb ai/acre and 10 lb ai/acre) to the soil surface. Three other
treatments consisted of soil drenches with Orthene 75S at three
rates (1 lb ai/100 gal, 2 lb ai/100 gal, and 10 lb ai/100 gal).
The plant types used in these tests were: 1) Dieffenbachia
maculata 'Perfection', 2) Brassaia actinophylla, and 3) Spathiphyl-
4. Results The 5% granular formulation is relatively safe to use on
Spathiphyllum and B. actinophylla at both rates used. Both rates
of 5% granular were, however, phytotoxic to Dieffenbachia. The
1 lb ai/100 gal rate of Orthene 75S was safe to use on
Spathiphyllum and Dieffenbachia. All other rates cause marginal
necrosis on these plants. All rates of Orthene 75S caused
significant phytotoxicity on Brassaia.
II. Studies with Experimental Compounds
A. SD-52618 see I B
III. Studies to Establish Chemical Controls Against Diaprepes abbreviatus, the
Sugarcane Rootstalk Borer Weevil
A. Preventative Applications
1. Objective To determine if soil incorporation of granular
insecticides would prevent soil and root infestation by Diaprepes
2. Need An alternative chemical to heptachlor is needed. In order
to meet the current USDA certification requirements, a material is
needed which will be 100% effective in preventing infestation by
this insect with one application.
3. Methods Plants were potted in soil which had insecticide
incorporated into it. Two rates (5 lb ai/acre and 10 lb ai/acre)
were used of a 5% granular formulation of Bendiocarb and a granular
formulation of Methoxychlor. After 3 and 4 months, 100 weevil
larvae were introduced into each pot to test the efficacy of the
residual. Two months after introducing the larvae, the soil and
roots in each pot were examined for the presence of healthy larvae.
4. Results No treatment was effective at killing 100% of the