NOTE: Below are the fire blight risk assessments, comparing graphics
from Maryblyt 7, and also from the Cougarblight model as shown on our NEWA site. We will be using the same weather data from our NEWA station to make these
comparisons. We thank Dr. Mizuho Nita for hosting the Maryblyt 7.1 download site.
CAUTION: The observations,
conditions, and recommendations reported for Winchester, VA are provided as a
guide to fire blight risk assessment only for the immediate area of the
Virginia Tech AREC located six miles southwest of Winchester. Use of the
information reported here for making orchard management decisions outside of
that area is not our intent. Fruit producers outside of that area are
encouraged to consult their state extension specialists for information similar
to that provided here.
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| Graphic from Maryblyt 7, April 23, 2018. Click to enlarge. |
FIRE BLIGHT: Above is a cropped
graphic from the Maryblyt 7 program. We are using Wednesday, Apr 14 as the date
of first bloom open on Idared and Pink Lady cultivars. The temperature and
rainfall data are current through Monday evening, April 23. Predicted weather
conditions are shown for April 24-27. The components of fire blight risk are
indicated in the columns labeled B (blossoms open), H (degree hours for
epiphytic bacterial populations), W (wetting by rain or dew), and T (average
daily temperature 60 F or above). For infection to be predicted, wetting
must occur after the EIP (epiphytic infection potential) reaches 100 or higher,
and this must coincide with an average daily temperature of 60°F or more. Based on
recorded temperatures and wetting, the risk column shows low to moderate risk
for Apr 23-27. With cooler predicted temperatures for the coming week or more,
fire blight risk should remain low to moderate. However, with warmer than predicted
temperatures, expect the risk to increase again.
Below is the graphic from the Cougarblight model as shown on our NEWA site. We selected orchard blight history option as “Fire blight occurred in your neighborhood last year” and first
blossom open date as 4/14/2017. Cougarblight shows color-coded risk assessment
as “Cougarblight 4-Day DH” which also remains low at least through Apr 27.
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| Cougarblight graphic from April 23, 2018. Click to enlarge. |
