DISEASES
Pecan Scab: A good portion of the eastern two
thirds of the state has received adequate to excessive amounts
of rain. The major threat to the crop in areas with all this
moisture will be pecan scab. In addition to rain, humid
conditions which allow for extended periods of heavy dew
also provides ideal conditions for scab development. In
fact heavy dew is probably worse than rain. Hard rains
can help wash scab spores off of leaves while heavy dew
allows scab spores on the leaf to germinate.
In many cases orchard floors might be to wet so aerial
application might be an answer. Aerial application of a
fungicide, although not as effective as a ground application
is a lot better than not doing any thing. With aerial applications
spreader stickers are not recommended and consider shorteningn
treatment intervals.
Pecan Scab photo by Dr.Chip Lee
Several producers without pesticide licenses and homeowners
have asked about available fungicides. I hate to say this
but we are really hurting in this area with very few if
any products available. For those without a license Topsin
M might be your best or only choice.
For commercial producers the following fungicides are
labeled for pecan:
Abound (azoxystrobin)
Flint (trifloxystrobin )
Enable (fenbuconazole)
Enable 75WSP/AgriTin
Orbit (propiconazole)
Orbit45WP/Supertin 80WP
Propimax (propiconazole)
Super Tin (triphenyltin hydroxide)
Stratego (trifloxystrobin)
Syllit 65W (dodine)
*** Grazing restrictions also apply to fungicides.
INSECTS
Aphids: Honey dew from blackmargined aphids is apparent
on the foliage. My general recommendation for blackmargined
aphid is to leave them alone. There are numerous beneficials
such as lady beetle, lacewings and spiders that help
maintain populations.
Cotton square borer: I’ve received several questions
concerning pecan nutlets that have been observed with nice
round holes and no frass, This damage is caused by larvae
of the cotton square borer. This insect is occasionally
found on pecan and does not represent any type of “economic” threat.
Fall webworm: Webs which are created by larvae of the
fall webworm are very apparent at this time. I’ve
received one report of very heavy FWW in Brazoria County.
In this particular orchard it has been noted that where
Confirm and SpinTor were applied for pecan nut casebearer
there are significantly fewer FWW webs as compared to
the Lorsban and untreated plots. This side benefit of
using these products for PNC was also noted last year.
Grasshoppers: I have not heard any state wide report on
grasshopper populations but I have noticed immatures
and adults in many orchards in the Brazos county area..
I’m
hoping that the wet conditions will help keep populations
down. If the situation arises and you need to treat,
treat the orchard floor, ditches and fence rows.
There are several products to choose from such as chlorpyrifos
(Lorsban 4E), carbaryl (Sevin 80S, 50W, 4L, XLR), diflubenzuron
(Dimilin 2L) esfenvalerate (Asana). Note - you will need
to take into consideration grazing restrictions if livestock
are present. Also, Dimilin 2L will only work on immature
grasshoppers.
Pecan nut casebearer: Second generation PNC should be
starting in the southern portion of the state. As a general
rule the second generation is approximately 42 days or
six weeks after the first. I recommend that new PNC pheromone
traps be placed in the orchard to monitor for this generation.
In most years insecticides are not required for the second
generation but I still recommend monitoring and scouting
for this second generation.
Stink bugs/ Leaffooted bugs: Although it is a little
early for this group of insects it is not to early to start
planning some type of management program - if you have
been having problems. This complex of kernel feeding insects
can feed on pecans up to the day of harvest. Feeding after
shell hardening causes the black spots on pecan kernels
at harvest.
Here are a few things to consider. Have you
had problems in the past? If you are in an area with
row crops - what crops have been planted?
Row crops such as soybeans and grain sorghum can produce
a lot of stink bugs. As these crops mature and are harvested
adult stink bugs can move into orchards. Also, with the
spring rains, alternate weed hosts are very plentiful
and might produce high numbers of leaffooted bugs and
stink bugs.
There is one species of stink bug which can be very numerous
in orchards and this is the rice stink bug. This insect
is slender, straw colored with two forward pointing spines
on the “shoulder area”. This stink bug is a
grass feeder only and is not a threat to pecans.
TEXAS PECAN GROWERS CONFERENCE
I hope all of you will be able to make it to the annual
TPGA Conference and Trade Show in San Antonio this year.
Call the TPGA office 979-846-3285 or visit their web site
at http://www.TPGA.org for more information. I will have
an exhibit booth again this year and hope you will come
by to visit.
Also this is a reminder that CEU credits will be given
during the conference and you will have to sign up each
day. Announcements concerning sign up location and CEU
credits will be made each morning.
COUNTY REPORTS
Burnet county: Up to 2 inches of rain across county. Webworm
activity is high. Crop is moderate and spotted but yard
trees look good. Minimal first generation casebearer
infestations
Comanche county: Good Wichita crop, Cheyenne is fair and
Pawnee is poor. Natives havesome top crop. Even with lots
of rain scab pressue id moderate overall. Pecan nut casebearer
activity was light.
Eastland county: Fair crop overall. Pecan nut casebearer
activity was light. The county has missed all of the big
rains but did receive 2 ½ inches last week.
Guadalupe county: Rain, rain and more rain. 6 - 8 inches
in two hours last week. Average crop and casebearer activity
was very light.
MEETINGS:
June 16-18, 2004
Louisiana Pecan Growers Annual Conference
Baton Rouge, LA
Contact: Frances Knox 318-747-3003 or
francesknox@bell-south.net
July 11-14, 2004
83rd Annual Texas Pecan Growers Conference and Trade Show
San Antonio, TX
Contact: TPGA - 979-846-3285
