Foliage Pests of Pecan
Will Hudson
Extension Entomologist
Objective : Protecting Pecan Foliage
Budbreak to Harvest
is 8 months
Pecan foliage has to
be conserved and
protected from insects
and diseases to
produce
photosynthate for
next season’s crop
and to reduce the
amplitude of alternate
bearing cycle
Foliage Pests
Aphids
– Yellow Pecan Aphid
– Black-margined Pecan Aphid
– Black Pecan Aphid
Mites
Phylloxerans
Caterpillars
Aphids
Short life cycle and high reproductive
potential result in explosive population
growth in favorable conditions
Lots of natural enemies, so biological
control can be effective
Scouting is critical
Both systemic and contact insecticides are
used
21
-M
28 ay
-M
a
4- y
J
11 un
-J
18 un
-J
25 un
-J
un
2Ju
9- l
J
16 ul
-J
23 ul
-J
30 ul
-J
6- ul
A
13 ug
-A
20 ug
-A
27 ug
-A
u
3- g
S
10 ep
-S
ep
Aphids/comp. leaf
Aphid Abundance by Date in Untreated
Trees
YPA
BMA
BPA
100
80
60
40
20
0
Predicting Aphid Outbreaks
Population Growth - Days to Double
aphid
BMA
YPA
June
28 C
1.8
2.1
July August Sept. Oct.
27 C 28 C 27 C
23 C
1.6
1.7
1.8
2.1
2.0
2.0
2.0
2.4
BPA
2.9
2.7
2.7
2.8
3.4
Kaakeh and Dutcher. 1992. Environ. Entomol. 21: 632-9.
Scouting for Aphids
Orchards should be scouted weekly
Examine a “random” sample of terminals
from trees throughout the orchard
Know how to identify the aphids
Recognize beneficials
Know your trees and orchard history
Keep up!
Yellow Pecan Aphid
May be found any
time during the
season
Winged adults are not
always present
Populations usually
peak in late summer
“Threshold” is 20 per
compound leaf
Black Pecan Aphid
Populations usually
peak in late season
Some varieties are
very susceptible to
damage
Feeding causes
chlorosis and leaflets
drop prematurely
Threshold is 15% 0f
terminals with >1
Lady Beetles
LADY BEETLE PUPA
Lacewings
Green Lacewing Eggs
BROWN LACEWING
BROWN LACEWING LARVA
LACEWING CAMOUFLAGE
SYRPHID FLY ADULT AND
LARVA
Pecan Aphid Chemical Control
Soil Treatment – Season-long chemical
control is effective with application of
systemic insecticide – Temik or Admire
Foliage Treatment - Reliance on beneficial
insects for control through early August
and foliage application of Dimethoate,
Fulfill, Centric, Provado + Lorsban, etc.
from then until October
Insecticide
Application Methods
aphids per compound leaf
Black-margined Aphid Abundance in
Insecticide-Treated and Untreated Trees
18
16
14
12
10
8
6
4
2
0
l
l
l
ay Jun Jun Jun -Ju -Ju -Ju Aug Aug Aug Sep
8 18 28 7- 7- 7- 6-M 8- 8- 89
1
2
1
2
2
Treatment oz form/a
Control
Admire - 16
Provado - 3.5
Black Pecan Aphid Abundance in
Insecticide-Treated and Untreated Trees
aphids per compound leaf
35
30
25
20
15
10
5
0
2
l
l
l
ay Jun Jun Jun -Ju -Ju -Ju Aug Aug Aug Sep
M 8- 8- 88 18 28 7- 7- 7- 691
2
1
2
Treatment –
oz form/a
Control
Admire - 16
Provado - 3.5
To Treat or Not To Treat
What aphid?
What else is there?
– Beneficials
– Other pests
Weather conditions
Cultivar
Time of the season
Pecan Leaf Scorch Mite
Feeding causes
“scorching” effect on
leaves
Mites are usually found
on underside of leaflet
Infestations often start
low in the center of the
tree
Symptoms look like some
diseases
Dicofol, Vendex, Temik
provide control
Photo by HC Ellis
Pecan Leaf Scorch Mite
Caterpillars
Most foliage feeders are minor in
importance
Usually infest only a few trees
Many insecticidal options are labeled
Sprays for other insects usually get these
also
Walnut Caterpillar
Fall Webworm
Phylloxera
Two types – stem and leaf
“Sucking bugs”, related to aphids
One generation per year
Once the galls form, control is difficult
Treat at bud-break, or go systemic
Leaf Phylloxera
Stem Phylloxera
Extension Programs
Annual spray guide
Scout school odd years
Field day Sep 8
Telephone hotline and direct line
– 1-800-851-2847
Websites and handbook
– http://sacs.cpes.peachnet.edu/pecan/
Grower association meetings
– GPGA annual meeting May 5 in Perry