Page 12 - Griffin Gazette Spring 2016

GerberaGrowing Gorgeous
By Tami Van Gaal,
GGSPro Technical Support Representative
Consumers love
daisies! And when
it comes to daisies,
nothing grabs
consumer attention
like a well-grown
gerbera. Big, bold
flowers drive sales
at the grocery store
floral counter and in
the garden center.
This nearly perfect retail opportunity can
also present growers with a few challenges.
Fortunately, GGSPro has solutions to the
most common gerbera production problems.
Implement a few changes, avoid a few pitfalls
and produce a spectacular crop.
Challenge #1: Thrips Control
Thrips are problematic on many crops and
have a stealthy ability to ruin a gerbera crop following spray strategies:
almost before growers know a problem exists.
Thrips are drawn to the developing flowers
very early, leaving highly visible streaking,
necrosis and distortion when the flowers
open. This same rasping feeding pattern also
damages young leaves, resulting in highly
visible feeding scars and distorted foliage.
With only a handful of flowers open at sale,
you can’t really afford to lose even a single
flower to thrips damage. An iron-clad thrips
control program is warranted.
Growers can use BCAs or chemistry to
control thrips. If using BCAs, begin treatment
with an inundative, bulk release of Amblyseius
12 Griffin Gazette Spring 2016
cucumeris at transplant to stop any larvae that
may have come in with the young plants. From
here, determine your strategy for treatment for
the rest of the crop cycle based on whether
or not a bridge of contact exists between the
plants. If pots are touching or share a bridge
of contact, turn to sachets. Use one Amblyline
Stick per shuttle tray. Replace sachets every
four to five weeks for continued production. If
pots don't share a bridge of contact, continue
with weekly releases of A. cucumeris.
A. cucumeris will control only the larval
stage, so partner the mites with control of
additional life stages for full control. The next another application of the tank mix four days
easiest life stage to target is the pre-pupal/
pupal stage, which is most often found on
the media. Control using drench applications
of the beneficial nematode Steinernema
feltiae (available as Nemasys, NemaShield,
Exhibitline and Sentry). Make applications
every two to three weeks, depending on
pest pressure.
Thrips can be also be controlled with
chemistry. GGSPro regularly recommends
a Kontos drench for superior thrips control
(see the digital Gazette for Kontos application
tips). The beauty of using Kontos is that
control also extends to aphids, spider mites
and whiteflies, essentially covering all the
bases for gerbera. Count back seven weeks
from your sell date to time your Kontos
application. This allows for several weeks for
uptake and a solid five weeks of control. Prior
to the Kontos application, plan one of the
Spray Rotation A:
Starting two weeks before the drench, make
two applications of Pylon (MOA 13) or an
Avid/Azatin tank mix (MOA 6 and UN); apply
twice at a 5-day interval
Follow with an Overture spray at the time of
drench (MOA UN, two weeks of control)
Spray Rotation B:
Two weeks before the drench, apply
a Botanigard/Azatin O tank mix series
(MOA UN): apply the tank mix followed
by BotaniGard alone four days later, then
after that. Mycotrol ESO may be subbed for
the BotaniGard, and AzaGuard or Molt-X may
be subbed for the Azatin O.
Follow with an Overture spray at the time of
drench (MOA UN, two weeks of control)
Mainspring presents another option for long-
term thrips control from a drench. Mainspring
moves very quickly into the crop and provides
long-lasting control for at least four weeks.
Keep in mind that thrips must be controlled
prior to drenching Mainspring. Scout carefully
and employ one of the spray strategies
outlined above.
See the digital Gazette for suggestions for
soft chemistry options for thrips control and
control of broad mites.
Challenge #2: Powdery Mildew
While not sensitive to a wide range of foliar
diseases, gerbera are particularly sensitive
to powdery mildew. In fact, gerbera will