Agriculture Reference
In-Depth Information
Shoots should be well exposed to sunlight. If collecting more than 60 to
70 days after petal fall, collect the first and second fully mature leaves below
the shoot tip. Collect only clean leaves that are typical of those on the tree.
Avoid those damaged by pests, diseases, weather, or mechanical injury, and
do not collect leaves showing unusual symptoms, unless they are typical of
the trees being sampled. Collect both the leaf blades and petioles by grasp-
ing the petioles (leaf stems) firmly and pulling them downward and away
from the shoot.
Repeat the leaf collecting process across the orchard or planting block,
much as you did for soil samples, collecting roughly 60 to 100 leaves in total
for each variety. If possible, collect from at least 5 to 10 trees and do not col-
lect all of your samples from a few trees planted closely together. Repeat for
different varieties and crops, if necessary.
Place the leaves inside a paper lunch sack and allow them to air dry at
room temperature until they are brittle. Transfer the leaves to the sample
bag provided by the analytical laboratory and send the samples to the labor-
atory.
TO WASH, OR NOT
Growers often ask whether they should wash the leaves before drying
them to remove dust or other contaminants. In general, most analytical
laboratories prefer that you do not wash the leaves. If the leaves are
dusty, covered with kaolin clay (Surround), or have recently received a
cover spray, you may want to wash them. The following guidelines are
courtesy of Cornell University's Agro-One Soils Laboratory.
Wash the leaf samples while they are still fresh and before they wilt. If
a large number of samples are involved, they may be stored overnight
in a refrigerator or ice chest to keep them from drying out.
