Agriculture Reference
In-Depth Information
problem and hope it will go away. Remember, you are trying to work with nature rather
than against it, using the resources at hand to help manage problems such as pests and dis-
eases.
The first step is to practice prevention. Correct vineyard layout, good soil preparation,
and selecting the right rootstock will help to ensure that your grapevines can resist many
problems. Next is maintenance. Plants that are weak or stressed through lack of water or
nutrition are more subject to predation by insects. Overcrowded vines with too much fo-
liage are more likely to develop fungal diseases due to lack of circulation. Weeds compete
with vines for resources and they also harbor diseases and pests. So keeping up with your
maintenance tasks through the year—watering, feeding, canopy management, and weed
control—helps to keep down the number of problems you have to deal with.
But inevitably diseases and pests will find your vines. When this happens, you want
to be sure which pests you have. Dealing with problems in the vineyard is a process of four
steps.
1. Observation
Your initial pest and disease control program should start with an ongoing visual ob-
servation of the vineyard. Walk through the rows and look for anything unusual or that
has changed significantly. In other words, know your vineyard. When you first discover
something you think is different, decide whether it is within the normal range or whether it
looks like a problem.
2. Identification
Consider what the elements of the problem are. Look at the growth. Is it weak or excessive?
Are shoots curling? Are leaves eaten or scarred? Is the color changed? Is there a distortion
of the leaf surface? Are insects present? Observe not only the leaves, grapes, and shoots,
but the trunk and roots. Snoop around and under the leaves, peel off some bark, and pick
off a grape. Is it only one vine? Is the problem localized or is it scattered throughout the
vineyard?
3. Diagnosis
After you have carefully observed the affected vines and compared them to healthy, normal
vines, you will begin to determine what is eating or damaging your vines. A number of
common problems are listed in the following pages. But if you cannot positively identify
a pest or disease, don't guess at it. Talk to other local growers and farmers. Consult your
local extension service or agriculture office. Consult a reliable online source, such as that
of your local extension, or a good national source like Cornell University or University of
California, Davis. An excellent printed resource is the UC Davis book
Grape Pest Man-
