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I N S E C T S
Pecan Nut
CaseBearer
Pecan nut casebearer, Acrobasis nuxvorella, overwinters as
partially grown larvae in small cocoons (hibernacula) located at the
junction of the bud and stem. Larvae leave the cocoons in the early spring
about the time the buds open, feed briefly (about two weeks) on the
exterior of opening buds and then bore into the young tender shoots, where
they mature and pupate.
Hickory Shuckworm
Mature larvae of Hickory shuckworm, Cydia caryana,
overwinter in pecan shucks found on the ground or the tree and emerge as
moths in mid-May. Spring development of hickory shuckworm coincides with
that of native hickory trees, which set fruit two to three weeks earlier
than pecans.
Nut Curculio
The adult nut curculio attacks immature pecans from mid-July to
mid-August. Females make shallow, crescent-shaped punctures with their
beaks in the shucks of immature nuts, and they deposit a single egg in
each nut.
Pecan Weevil
The adult pecan weevil typically emerges from the soil as early as
July 25, frequently two to three days after a heavy rain. Adults cause two
types of nut damage, depending on the stage of nut development during
attack. Adults feeding on nuts before the gel stage (i.e., in the water
stage, usually before shell hardening) induce kernel shriveling and
blackening and premature nut drop.
Pecan Phylloxera
Three species of phylloxera (Phylloxera devastratrix) are
pecan pests, but only the pecan phylloxera causes economic damage in
certain years. The pecan leaf phylloxera and the southern pecan leaf
phylloxera feed primarily on the foliage, whereas the pecan phylloxera
attacks the foliage, shoots and fruit and is therefore the most damaging.
D I S E A S E S
Pecan Scab
The pecan scab fungus (Cladosporium caryigenum) overwinters
as a small, tight mat of fungal material called a "stroma" on
shucks, leaf petioles and stems infected the previous season. With warmer
temperatures and rainfall in the spring, fungal spores are produced on the
stroma. Dew and rain spread spores locally within a tree, and the wind
spreads them over long distances to adjacent trees or orchards.
Back to Hickory and Pecan Trees
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