In
some vineyards in the eastern part of the state, sharpshooter
leafhoppers, the vectors of Pierce's disease, are of
concern. While research is needed on the vector relationships and
timing in Virginia, several control options are available to
growers. The neonicotinoids Assail 70WSP (1.1 oz/A), Assail
30SG (2.5 oz/A), Belay 50WDG (4-6 fl oz), Venom 70SG (1-3 oz/A,
and Venom 20SG (0.44-0.66 lb/A) are registered for control of
sharpshooters. Use the higher rates for higher pest
pressure. In addition, Scorpion and Venom are
registered for soil application (9-10.5 fl oz, 5-6 oz/A,
respectively), as are Admire 2F (16-32 fl oz/A) and Admire Pro
(7.0-14.0 fl oz/A) are registered. Soil application should
be performed between bud break and pea-berry stage. A
successful approach has been to split the application of Admire
Pro in two appolications applied through drip irrigation.
Sharpshooter sprays will be most useful following winters with
three or fewer nights below 15 degrees F. Assail is limited
to two applications, and Venom to three applications per season. The most
appropriate timing is provisionally in late April or early May,
and the first week of July.
In addition to neonicotinoids, the following pyrethoids are
registered for sharpshooter control: Danitol 2.4EC (10 2/3 -
21 1/3 fl oz/A), Brigade 2EC (6.4 fl
oz/A), Brigade 10WSB (16 oz/A), Sniper 2, Baythroid XL (1.6-3.2 fl
oz/A) and Baythroid 2EC (1.6-3.2 fl oa/A). Danitol is
limited to 2 applications, Baythroid to 4 applications, and Brigade to
2 applications at the low rate, and one application at the high
rate. Pyrethroids may induce outbreaks of grape mealybug,
the vector of grapevine leafroll virus.