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not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
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Copyright 2005, Board of Trustees, University
/5 Central Science
University of Florida
OCT 23 1987
CENTRAL FLORIDA RESEARCH AND EDUCA ION CENTER
SSanf o, F a Univers;ty of Florida
Sanford, Florida I-
Research Report San 86-06 September 1985
EFFICACY OF INSECTICIDAL SEED COATINGS FOR EARLY INSECT
CONTROL IN FIELD CORN GROWN IN SANDY AND ORGANIC SOIL, 1984
G. L. Lelbee
Field corn 'Asgrow RX 114' was coated with Larvin-3.2 F at the rate
of 4 and 8 oz. -of al/100 Ib of-seed-and Orthene 75 SP at 8 and 12-oz of
al/100 Ib of seed.' The seed was coated by shaking 200 grams of seed In
a 1000 ml polyethylene bottle for five minutes with the appropriate
amount of material. To promote-better coating-of the seed for the dry
Orthene formulation, the seed was wetted by shaking it for 2 minutes
with 1.4 ml of water in the bottle prior to Introducing the Orthene.
The seed was spread onto cafeteria trays and air dried In-a greenhouse.
Twenty 4-inch plastic pots of unsterilized soil were prepared for each
treatment; 10 pots of Myakka fine sand from the CFREC, and 10 pots of
Lauderhill muck from Zellwood, FL. Five seeds per pot were planted 3/4in.
deep on Feb. 2, 1984. Untreated seed was used to prepare an untreated
check for each soil type. All pots were watered equally only when the
soil surface was dry to the-touch. The field corn spiked on Feb. 8 and
was in the two-leaf stage and 1.5 1.75 in. tall on Feb. 11. The
plants were In the three-leaf-stage and 2.5 3.0 in. tall on Feb. 13.
On-Feb. 13, approximately 1 in. of the second leaf was clipped from each
plant and placed into a-labeled pill cup. Immediately after this was
completed, 3-first Instar black-cutworm, Agrotis ipsilon, larvae were
placed on each leaf clipping-and the pill cups sealed with paper lids.
The mortality of the black cutworm larvae was recorded one and two days
later. A similar bioassay was set up on Feb. 20 when the plants were in
the 4-5 leaf stage and 5-6 in. tall.
The results of the first bioassay are presented In the table.
There was no significant-activity in the second bioassay. The only seed
treatments that showed-any activity were Orthene 75 SP at 8 and 12 oz of
al/100 lb of seed in sandy soil. These same treatments showed no
activity In the muck.
Soil Treatment % mortality % mortality
type (al/100 lb of seed) one day* two days*
Sand Untreated check 1.8 b 8.5 b
Larvin 3.2 F 4 oz. 1.7 b 9.6 b
Larvin 3.2 F 8 oz. 10.6 b 10.0 b
Orthene 75 SP 8 oz. 49.1 a 86.5 a
Orthene 75 SP 12 oz. 75.7 a 95.0 a
Muck Untreated check 0.0 b 5.5 b
Larvin 3.2 F 4 oz. 1.7 b 10.3 b
Larvin 3.2 F 8 oz. 0.0 b 6.0 b
Orthene 75 SP 8 oz. 1.5 b 10.1 b
Orthene 75 SP 12 oz. 1.8 b 4.0 b
*Means within each column followed by the same letter are not
significantly different at-the 5%-level by DMRT. Analyses were
performed on transformed (arc sine) data.