Group Title: Research Report - University of Florida Research and Education Center ; 87-06
Title: Bioassay of two new insecticides, F4922 and F5951, in the laboratory against Liriomyza trifolii (Burgess)
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 Material Information
Title: Bioassay of two new insecticides, F4922 and F5951, in the laboratory against Liriomyza trifolii (Burgess)
Series Title: Research Report - University of Florida Research and Education Center ; 87-06
Physical Description: Book
Language: English
Creator: Leibee, Gary L.
Publisher: University of Florida, Central Florida Research and Education Center
Publication Date: 1985
 Record Information
Bibliographic ID: UF00076083
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 122930932

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University of Florida OCT 23 19
Sanford, Florida University of FIc

Research Report SAN87-06 October 1-I 6


Gary L. Leibee

F4922 and F5951 (FMC Corporation) represent two related members of
a new class of foliar insecticide. These insecticides were evaluated at
0.05, 0.1, and 0.2 lb. ai/acre against the larval stage of Liriomvza
trifolii (Burgess) using a leaf-dip technique in the laboratory. An
untreated check and Pounce (permethrin) at 0.2"lb ai/acre were also
included in the bioassay. Cowpeas in the primary leaf stage were
exposed to L. trifolii adults for 24 hrs in an infestation cage. The
infested plants were maintained at 25-27C for two days before dipping
to allow the eggs to hatch. The leaves and part of the stem were
submersed for 5 seconds into the appropriate solutions and the excess
material shaken off. Ten plants were used for each treatment. The
concentrations of the solutions were based on 50 gpa. X-77 was added at
the rate of 8 oz per 100 gal to improve wetting of the plants. The
untreated checks were dipped in water containing only X-77. The dipped
plants were maintained in growth rooms at 25-27 C. Four days after
dipping, the number of leafmines was recorded for each plant and the
primary leaves excised and placed in plastic Petri dishes with covers.
The Petri dishes contained filter paper to absorb excess moisture to
prevent the emergent larvae and pupae from drowning. The leaves were
left in the Petri dishes one week to allow all the larvae to exit and
pupate. The puparia were removed from the Petri dishes, counted, and
placed into plastic pill cups. Adult emergence was recorded after all
the adults were observed to be dead. Percent larval survival was
calculated by dividing the number of pupae reared from a plant by the
total number of leafmines in that plant. Similarly, percent survival to
the adult stage was calculated by dividing the number of adults reared
from a plant by the number of leafmines in that plant. The latter
accounted for additional mortality that occurred in the pupal stage.

F4922 was very effective against L. trifolii. F4922 was superior
to F5951 in its activity against the larvae. Additional mortality
occurred in the pupal stage with both compounds, which reduced the net
difference in total activity between the two insecticides. Additional
mortality in the pupal stage was so great in the Pounce treatment that
the significant differences that occurred in larval survival between
Pounce and the 0.1 and 0.2 rates of F5951 were removed. Both F4922 and
F5951 caused a deformity in the puparium that apparently prevented the
emerging adult from freeing itself from the puparium. The hind legs
appeared to be stuck to the inside of the puparium. This deformity did
not occur in the untreated check and Pounce treatments. No
phytotoxicity was observed.

% larval % survival to
Treatment survival* adult stage*

Untreated check 98 a 88 a

Pounce 3.2EC 0.2 51 b 16 b

F4922 0.78EC .05 9 de 3 c

F4922 0.78EC 0.1 4 e 0 d

F4922 0.78EC 0.2 3 e 0 d

F5951 0.78EC .05 42 bc 24 b

F5951 0.78EC 0.1 23 ed 11 be

F5951 0.78EC 0.2 20 cd 12 b

Means within each column followed by the same letter are
not significantly different at the 5% level by DMRT.
ANOVA was performed on transformed (arc sine) data.

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