Control Of Grape Leafhopper On'
Lake Emerald Grapes ., ,
W. C. Adlerz
University of Florida IFAS \ -
ARC Leesburg "
August 21, 1980 ,.i *
Grape leafhoppers, Erythroneura comes (Say) (Homptera:.JCicade -
lidae) breed on bunch grape plants and may damage them' ly.
Adult and young leafhoppers feed in the undersides of leaves, re-
moving chlorophyll and leaving pale feeding spots that are visible
from above. Feeding spots may be so numerous as to cause yellowed
leaves and even leaf drop. Excreta from these insects may collect
on the fruit which will then be spotted and possibly covered with
sooty mold. To keep plants as vigorous as possible, and to produce
cleaner fruit, leafhoppers should be controlled. Several experi-
ments have been conducted on Lake Emerald grape to determine if
some newer insecticides will perform better than the standard, and
to establish the best pattern of use for them and the standard Sevin.
Procedure: Insecticides were applied to 4-plant plots replicated
6 times. Treatment schedules are listed in the various tables.
Insecticides were applied in 100 gallons of water per acre using a
Solo Mistblower Model 410.
Results: The effects of various insecticides and application
schedules are shown in Tables 1-3.
In 1976 all three insecticides significantly reduced leafhopper
populations from pre-treatment levels of July 12 (Table 1). Control
by Orthene was more persistent than that by the two synthetic
pyrethroid materials, and was significantly better than the other
treatments after 53 days.
The standard Sevin gave very good control of grape leafhopper in
a 1977 test (Table 2), but Orthene at 0.5 pounds active ingredient
per acre as a single post bloom spray gave significantly better con-
trol in most cases.
In 1980, Orthene at various rates of application was compared with
Mesurol. Mesurol is a carbamate insecticide which has the additional
quality of repelling some species of birds. Both insecticides
significantly reduced leafhopper populations from pre-trec;'+-nnt
levels of June 16. Control with Mesurol persisted until July 22
(35 days) while control with Orthene at 0.5 and 1.0 pounds per acre
was still effective August 11 (62 days). Orthene was very effective
at the lowest rate tested, 0.125 pounds.
Leesburg ARC Research Report (WG 80-6)
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Table 1. Control of grape leafhopper on Lake Emerald grape, 1976.
AI/100 Average leafhopper/10 leaves
TreatmentI gal 7/12 7/16 7/22 8/3 8/20 9/3
Orthene 75SP 1.0 15.8 0.17 a 0.00 a 0.67 a 2.00 a 8.00 a
0rthene 75SP 0.5 16.9 0.50 a 0.17 a 1.17 a 1.83 a 6.17 a
(3.2/gal) 0.1 13.9 3.17 a 2.33 a 6.00 be 5.50 ab 15.83 b
(2.4/gal) 0.1 13.8 1.67 a 1.50 a 2.50 ab 11.67 bc 17.83 b
(3.2/gal) 0.05 14.1 4.50 a 5.17 a 5.00 b 11.17 bc 18.33 b
Benlate 50W 1.00 11.2 20.50 b 10.67 b 8.67 c 14.50 c 20.33 b
Application date July 13.
Table 2. Control of grape leafhopper on Lake Emerald
grape with Sevin and Orthene applied on
various schedules, 1977.
Pounds Average leaf-
Treatment AI/100 hoppers per 10
schedule1 gal leaves June 17
A Pre-bloom plus monthly Sevin 1.0 1.67 a
B Single post-bloom Orthene 0.5 1.67 a
C Post-bloom plus monthly Sevin 1.0 3.50 b
D Single pre-bloom Sevin 1.0 6.00 b
E Single post-bloom Sevin 1.0 6.33 b
F No Spray -- 14.17 c
1Applications: D, April 8; E, B. April 28; C, April 28,
May 27; A, April 8, May 13, June 14.
Table 3. Control of grape leafhopper on Lake Emerald grape with
Orthene at various concentrations and with Mesurol, 1980.
AI/100 Average leafhoppers per 10 leaves
TreatmentI gal 6/16 6/27 7/1 7/9 7/16 7/22 8/5 8/11
1Single application made June 17, 1980.
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