HISTORIC NOTE

The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
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site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida

GULF COAST STATIO-1 MIMEO REPORT 56-5 ,- "* "
Brode;ton, Floridn

NOTES ON GLADIOLUS DISEASE RESEARCH 1956 MAY 1-4 1956

R. O. Magie

Controlling Leaf and Flower Diseases

Manzate and Orthocide 50W were compared with Parzate and Parzate Liquid-zinc

sulfate sprays in plots of Picardy bulblets, planting stock and large bulbs. The

Botrytis and Curvularia diseases were encouraged by inoculations and overhead ir-

rifetions. Maneb (Mqnzate or Dithane M-22) was most effective. Zineb (Parzate

and Dithane Z-78) was almost as effective as maneb and was definitely more effec-

tive than nabam + zinc sulfate (Dithane D-14 or Parzate Liquid), especially in con-

trolling Botrytis. Captan (Orthocide) gave poorer control than the other spray ma-

terials. Maneb and zineb were used at 2 lbs.-l0 gals.,captan 50W at 3-100, and

nanbm at 2 quarts + 3/4 lb. zinc sulfate in 100 gallons.

It is now recommended that zineb be used instead of nabam plus zinc sulfate.

The indications are that better disease control and plant nutrition will result

from a spray schedule using both zineb and m-neb. Zineb will give longer protec-

tion than maneb. Therefore, use zineb in dry weather or before the dieases:appear,

spraying once a week. After the disease begins to spread and wetting periods are

frequent, maneb should be altorn-ted with zineb, using 1 1/2 lb. maneb powder in

100 gallons and spraying twice each week, once with mpneb and once with zineb.

Then rain or fog occurs frequently and the plants are growing rapidly, especially

young bulblets and flower spikes, it will probably be necessary to spray three

times each week, once with zineb and twice with maneb,

In order to keep the spray droplets from running together on the new, waxy

growths, a wetting agent is added to the spray mixture. Use only enough wetter

to cause the droplets to flatten out slightly on young leaves or spikes.

GULF COAST STATIO-1 MIMEO REPORT 56-5 ,- "* "
Brode;ton, Floridn

NOTES ON GLADIOLUS DISEASE RESEARCH 1956 MAY 1-4 1956

R. O. Magie

Controlling Leaf and Flower Diseases

Manzate and Orthocide 50W were compared with Parzate and Parzate Liquid-zinc

sulfate sprays in plots of Picardy bulblets, planting stock and large bulbs. The

Botrytis and Curvularia diseases were encouraged by inoculations and overhead ir-

rifetions. Maneb (Mqnzate or Dithane M-22) was most effective. Zineb (Parzate

and Dithane Z-78) was almost as effective as maneb and was definitely more effec-

tive than nabam + zinc sulfate (Dithane D-14 or Parzate Liquid), especially in con-

trolling Botrytis. Captan (Orthocide) gave poorer control than the other spray ma-

terials. Maneb and zineb were used at 2 lbs.-l0 gals.,captan 50W at 3-100, and

nanbm at 2 quarts + 3/4 lb. zinc sulfate in 100 gallons.

It is now recommended that zineb be used instead of nabam plus zinc sulfate.

The indications are that better disease control and plant nutrition will result

from a spray schedule using both zineb and m-neb. Zineb will give longer protec-

tion than maneb. Therefore, use zineb in dry weather or before the dieases:appear,

spraying once a week. After the disease begins to spread and wetting periods are

frequent, maneb should be altorn-ted with zineb, using 1 1/2 lb. maneb powder in

100 gallons and spraying twice each week, once with mpneb and once with zineb.

Then rain or fog occurs frequently and the plants are growing rapidly, especially

young bulblets and flower spikes, it will probably be necessary to spray three

times each week, once with zineb and twice with maneb,

In order to keep the spray droplets from running together on the new, waxy

growths, a wetting agent is added to the spray mixture. Use only enough wetter

to cause the droplets to flatten out slightly on young leaves or spikes.

Maneb may stop development of some of the newly-started infections. There-

fore, if a disease is spreading and prolonged rain occurs, use mnneb spray as soon

as the plants dry off. The main reliance, however, should always be placed on the

protective notion of zineb and mnneb because maneb's curative action is only per-

tl-l. The aim should be to have the newly-exposed leaf and flower tissue covered

iih spray before the rmin or dew periods and to use the curative action of m,bas

o lhelp out in emergencies.

,-neb has been used by several growers during the past two years with little

cr no injury. However, test plants have been severely injured wheln the spray did

no'; dry off before night. The leaves and spikes were injured in cool as well as

warm weather. The following precautions should be taken with mineb spray:

1. Do not drench the spikes.
2. Spray plants early enough so they will dry completely before
night.
3. Never spray when plants are wet with dow or rain.

If the plants cannot be sprayed, dust them with zineb or meneb. The dust mix-

tures should contain 5 to 6 percent of active ingredient. Light dusting applied

every third or fourth day ore more effective then a heavy dusting made once a week,

Flower Dip for Botrytis Control

The Botrytis disease causes a soft rot of petals and a slimy breakdown of

rnikes in transit and cold storage. Considerable damage may result from n few

petal infections too small to be seen when spikes are packed. This can be held

fairly well under control by dipping the heads and part of the stens in zineb

~;'stable powder (Parzate or Dithane Z-78) spray mixture. Use one pound of the

,ettPhle powder in 50 gallons of water plus 2 oz. of a wetting agent. Keep it

stirred up and dip the bundles for about two seconds as soon as they are received

at the packing house. Before packing, shake the spray out of the buds because ex-

cess spray inside the bud sheaths may cause burning in warm weather. If zineb

causes too much visible residue, use nabam plus zinc sulfate mixed as for field

crying.

-3-

Other materials which hold down the spread of Botrytis in the package are Von-

cirde "51", 1/2 pint to 50 gallons, and Puratized Agricultural Spray, 1/2 pint in 50

gallons. Add 2 oz. of a good wetting-penetrating agent such as Triton X-100. The

spike dip is not a substitute for regular and thorough spraying or dusting in the

field because dipping will not stop the development of infections which have al-

ready taken place.

Now train of Curvularin Fungus

Curvularia infection was found on planting stock of Snow Princess, Valerin,

Hoprmns Glory, Morning Kiss and other varieties for the first time. This appears

to be a new strain capable of attacking varieties which h-ve been free of infection

rn' ti recently. All varieties, especially planting stock and bulblets, henceforth

should be sprayed each week regularly from the time of emergence. This new strain

may explain the severe rotting of bulbs by Curvularin seen in recent years.

Fusnrium Control

Pre-storoge Bulb Treatments

Practically all bulb treatment tests show that flower and bulb yields are in-

creased by treating the bulbs. This is true for all varieties tested.

Large apnd Jumbo bulbs treated when cleaned and again before planting. For

dust treatment, use Spergon wettable powder diluted 1-1 or capton (Orthocide) 50T

diluted 1-3 (12..54). Pyrophyllite (Pyrox) or 54 DDT may be used as the diluent.

Dust should be applied immediately after breaking off old bulb when the scar is wet.

For dip treatment, use 6 lb. captan 50' mixed in 50 gal. water. Stir vigorous-

ly between batches. Do not put bulbs in burlap bags. Soak bulbs 15 to 30 minutes.

Where bulbs must be treated in burlRp bags, use Dowicide B, 2 lb. per 50 gal.

plus 1/2 cup of Triton X-100 (do not use Tergitol Dispersant TON with Dowicide B).

So:-k bulbs 15 minutes. Dip treatments cn be delayed as much as 24 hours after

clea ing bulbs.

-3-

Other materials which hold down the spread of Botrytis in the package are Von-

cirde "51", 1/2 pint to 50 gallons, and Puratized Agricultural Spray, 1/2 pint in 50

gallons. Add 2 oz. of a good wetting-penetrating agent such as Triton X-100. The

spike dip is not a substitute for regular and thorough spraying or dusting in the

field because dipping will not stop the development of infections which have al-

ready taken place.

Now train of Curvularin Fungus

Curvularia infection was found on planting stock of Snow Princess, Valerin,

Hoprmns Glory, Morning Kiss and other varieties for the first time. This appears

to be a new strain capable of attacking varieties which h-ve been free of infection

rn' ti recently. All varieties, especially planting stock and bulblets, henceforth

should be sprayed each week regularly from the time of emergence. This new strain

may explain the severe rotting of bulbs by Curvularin seen in recent years.

Fusnrium Control

Pre-storoge Bulb Treatments

Practically all bulb treatment tests show that flower and bulb yields are in-

creased by treating the bulbs. This is true for all varieties tested.

Large apnd Jumbo bulbs treated when cleaned and again before planting. For

dust treatment, use Spergon wettable powder diluted 1-1 or capton (Orthocide) 50T

diluted 1-3 (12..54). Pyrophyllite (Pyrox) or 54 DDT may be used as the diluent.

Dust should be applied immediately after breaking off old bulb when the scar is wet.

For dip treatment, use 6 lb. captan 50' mixed in 50 gal. water. Stir vigorous-

ly between batches. Do not put bulbs in burlap bags. Soak bulbs 15 to 30 minutes.

Where bulbs must be treated in burlRp bags, use Dowicide B, 2 lb. per 50 gal.

plus 1/2 cup of Triton X-100 (do not use Tergitol Dispersant TON with Dowicide B).

So:-k bulbs 15 minutes. Dip treatments cn be delayed as much as 24 hours after

clea ing bulbs.

-4-

rInre sind umbo bulbs treated only at cleaning timo. Soak 30 minutes in

Dovricile B, 2 lb. per 50 gal. plus wetting agent. If bulbs have not been well

cured, use capten dip or one of the dusts, because DowiciTe B may injure the bulb

surface.

Pre-planting Bulb Treatments

InS.re nd jumbo bulbs treated when cleaned and again before planting. For

b.al.s treated with Dowicide B at cleaning time, use the 1 minute N.I.Ceresnn dip.

Qne poun- N.I.Coresan plus 1/2 cup wetting egent per 50 gallons. For bulbs treated

othrw.se, use 5 Ibs. (4 lbs. in cool weather) Dw'icide 3 in 50 gallons plus w~et-

ti-n nrgent, nrd soak bulbs for 15 to 20 minutes.

L-ire anai jumbo bulbs treated only before planting. Use 3 lbs. (4 lbs, ii

cool losther) of Dowicide B in 50 gallons with Triton X-100 spreader nnd sonk 20

to 30 minutes. Treatment may be mnde a few days before planting. In case bults

have sprouts and roots grown out, trert in cnptnn dip.

Sniller bulbs lnd bulblets. Soak bulbs for 5 to 15 minutes and bulblets for

30 minutes in N.I.Ceresnn solution. Plant immediately in moist soil. Bulblets

given tho hot-wtater treatment do not need to be dipped.

Hot WIter Treatment for Bulblets

The prospects of producing disease-free bulbs have been greatly improved by

the development of a hot-waiter treatment by Roistacher and Bald. Our tests show

th'it the treatment eliminates infections of Fusarium, Curvulnrin and Stromatinir

on bulbl.ts. Probably latent Fusarium infections are also cured but final proof

of this will only come from years of experience.

This treatment is relatively inexpensive and can be carried out on any farm.

The recommended procedure follows:

The time to heat-treat bulblets is during May, June and July. Bulblots dug

in these months are most likely to be dormant enough to tolerate the heat treatment.

-5-

Those du; in the winter probably sre not dormant enough and most of them would be

killed. About 4 to 8 weeks after digging, soak the bulblets in cool vnter for twc

days. (One day is sufficient if a half-cup of wetting agent such as Tergitol Dis-

persnnt TMT or Triton X-100 is added to each 100 gallons). Skim off and discard

nil bulblets that float. This is important in controlling Fusnrium disease. Put

ic-',e good bulblets in sacks about 2/3 filled, And soak them for four hours in forn-

~lin solution 1-200 (1 quart formalin in 50 gal. water). Formalin is a 40% solu-

tion of formaldehyde.

ifraediately after the formalin soak, place the sacks of bulblets in water

heated to 137 F or a little higher, so that the cold bulblets will drop the tem-

perature to 135" F. Have cold and boiling water handy to add to tank as needed

for adjusting the temperature quickly. Hold the temperature at 135' F as closely

as possible for 30 minutes. The water must be circulated and kept at nn even tem-

perature throughout the tank.

Remove the sacks promptly and immediately plunge them into a large volume of

cold winter to stop the treatment at 30 minutes. Pour bulblets into clean trays

pnr, when dry, place them in cold storage for four months, or until time to plant.

Minimum equipment needed: Two or more dairy thermometers. Some method of

h0e'tin? water in tank Equipment to circulate the hot water through the bulblets.

Extr- tanks for formalin solution and for cold water.