Preliminary Results June 17

Treatments Rate/acre Leafhoppers/0l leaves

Sevin, pre-bloom + 1 month 1.0 1.67
Orthene, post bloom 0.5 1.67
Sevin, post-bloom + 1 month 1.0 3.50
Sevin, pre-bloom 1.0 6.00
Sevin, post-bloom 1.0 6.33
No treatment 14.17


Evaluated 70 days after pre-bloom and 50 days after post bloom
application.

Results 1976: Orthene and two new synthetic pyrethroid materials
gave excellent control of grape leafhoppers, but the effects of
Orthene were more persistent.

1976 Thrips Control Test: A synthetic pyrethroid material,
FMC 33297, gave excellent control of thrips. Guthion and
Orthene were very good and somewhat better than Cygon.

In a second test, Lannate was more effective than Diazinon,
Guthion, and Malathion. Guthion and Malathion gave good control.



Disease Control of Bunch Grape in Florida (D. L. Hopkins)

Disease control is an absolute necessity to successful bunch grape
production in Florida. The most severe fungal disease is an-
thracnose, which affects both foliage and fruit. There are 3
other fungal fruit rots black rot, ripe rot, and bitter rot -
that must be controlled. A number of leafspot diseases become
serious problems during late summer. These diseases must be
controlled to prevent premature defoliation in the fall, thus
assuring a stronger vine in dormancy and better yields the
following year.

A long growing season, high temperatures, abundant rainfall,-and
high humidity make grape diseases very difficult to control in
Florida. Therefore, a vigorous spray program must be started in
the spring when buds are 2-6 inches tong and continued throughout
the season. Fungicides should be applied every l0-14 days until
a week before harvest, and every 3-4 weeks from harvest through
November or until dormancy.

The fungicides Manzate D, Dithane M-22 Spe.atal, Captan, Phaltan,
and Benlate are effective in controlling grape diseases in
Florida. In recent tests, Benlate and Captfan haze been especially
effective in controlling black rot, thus increasing marketable
yields. A spreader-sticker may be included in the spray. A
winter spray of lime sulfur, 2 qts. of 26-31% solution per 100
gallons of water (1 1/4 tablespoons/gal) is suggested for
anthracnose control.