Preventative Fungicides for FallPlanted Bulbs: Assessing the Options
September 2014
As autumn draws near, growers preparing to plant fall flower
bulbs need to keep a watchful eye. Careful physical inspection
of bulbs upon arrival is the first step in disease management.
Bulbs have often been in transit for several weeks; how
they were packed can impact quality. Upon opening your
shipment, be wary of packaging that’s overly wet or smells
bad. Any signs of visible mycelium, colored spores, soft rot,
discolored bulb scales or a sour smell point toward a problem.
If detected, be sure to notify your bulb supplier immediately
and discard infected bulbs.
Pots, flats, trays, tools and rooting rooms should always
be thoroughly cleaned and sanitized prior to use; doing
so will further help to prevent the need for fungicides.
Key environmental factors such as relative humidity and
temperature during storage, as well as in rooting rooms, can
impact flower bulb health.
The optimum pH range for soilless media is 5.5 to 6.5, with
low soluble salts. Furthermore, the soil medium should be
moist prior to planting bulbs with an ideal soil temperature
of 50-63°F. Well-drained, sterile planting media mixes include
Fafard® 2 or 3B, Sunshine Mix 1 or 4, and Metro Mix 360 or
510. Pro Mix BX is a soil mix enriched with Bacillus subtilis to
prevent root diseases, which may reduce the need to apply
fungicide drenches. No matter which media is ultimately
utilized, it’s imperative that the mixture is light in weight but
heavy to anchor bulbs and should not compact easily so as to
provide oxygen to roots.
Bulbs dipped or drenched with fungicides avert many bulb
diseases from occurring. Bulb dips for Fusarium, Penicillium
and Rhizoctonia can be achieved using Cleary’s 3336® at 1
to 1.5 oz./gal. for 30 minutes. Another option is KleenGrow™
Featured Products for Drench or Dip
Product
at 0.13-1.0 oz./gal. as a bulb dip, submerging bulbs from 30
seconds to five minutes to control Penicillium, Xanthomonas
and Fusarium bulb rots.
Fungicide drenches labeled for Rhizoctonia and/or Fusarium
control include Cleary’s 3336, OHP 6672™, Terraguard, or Medallion. When tank-mixed with fungicides Segway, Subdue
or Terrazole, Pythium and Phytophthora control is gained.
Truban fungicide offers control of Pythium and Phytophthora
but Truban EC cannot be tank-mixed whereas Truban WP can.
Banrot and Hurricane fungicides combine two active ingredients that offer full control of the aforementioned diseases.
Trichoderma virde, a pathogen
found on tulip roots, shows up
in the greenhouse, not in the
cooler. Therefore, treatment
must occur prior to disease
onset. As a preventative
measure, apply Kleengrow at
38 oz. per 100 gal. when tulips
are first taken out of the cooler
and then again in two weeks,
at 15 oz. per 100 gal., as a soil
drench. Trichoderma virde Tulip root system infected with
occurs only on lower roots. Trichoderma virde
Watch
for
glassy-looking
roots, which can become covered in white fungal hyphae.
When the disease is too late to treat, the roots begin to rot and
turn light to dark brown in color.
Read and follow all label directions. Not all products are registered for use in all states or for all crops. Products other than
those mentioned may also be safe and effective.
Featured Products for Drench Only
Size
Item No.
Product
Size
Item No.
Cleary’s 3336 F
1 qt.
71-2575
Banrot 40% WP
2 lbs.
71-1210
Cleary’s 3336 WP
2 lbs.
71-2565
Hurricane WDG
8 oz.
71-14751
2.5 gal.
71-2670
Medallion WDG
8 oz.
71-16502
2 lbs.
71-2672
Segway® O
16 oz.
71-31101
2.5 gal.
71-3200
Subdue® MAXX®
1 qt.
71-2979
Transom 50 WSP
2 lbs.
71-3195
Terrazole 35% WP
2 lbs.
3183862
KleenGrow
1 gal.
74-21101
Terrazole L
1 qt.
71-3025
Terraguard SC
1 qt.
71-3018
Truban® 30% WP
2 lbs.
71-3065
Truban® 25% EC
1 qt.
71-3070
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OHP 6672 4.5 F
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OHP 6672™ 50 WP
Transom™ 4.5 F
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