Note: Descriptions are shown in the official language in which they were submitted.
1317217
METHOD FOR CONTROLLING PLANT DISEASES
AND MICROORGANISMS IN THE PRESENCE o~ P~ANTS
.. . . ... .. .. _ _ ,
Background of the Invention
This invention relates to plant dlseases and
deleterious microorganisms found in environments adapted
for the growth of higher order plants, and more particu-
larly to control and inhibition of plant diseases and
deleterious microorganisms found in such environments.
In environments adapted for the growth of plants
of higher biological development or complexity than micro-
organisms such as bacteria, yeast, algae or simple fungus,
that is, in environments adapted for the growth o~ higher
order plants, development of such microorganisms on practi- -
cally any moist surface has been a longstandlng and
intractable problem.
Greenhouses contain a myriad of water sources,
including irrigation water, irrigation water run-off,
spilled water, cleaning water, condensation, atomized water
drifting from a humidifier or evaporative cooler and
extraneous sprayed water as might result from a water
hose. Since almost all surfaces in a greenhouse tend to
become moist from these sources, nearly any surface in a
greenhouse may serve as a site for microorganism growth.
Thus, in conventional greenhouses, microorganisms inevit-
ably colonize and grow not only on the plants themselves,but also on all other surfaces such as walls, ceilings,
floors, flower pots, flats, irrigation mats, irrigation
equipment and evaporative cooling pads.
~ Similarly, in outdoor nurseries, crop fields, and
any other environment, such as lawns or golf courses,
1317217
adapted for the growth of higher order plants,,micro-
organlsms tend to develop on irrigatLon or sprinkling
equipment, soil and the plants themselves, and containers
and planters.
Growth of miceoorganisms often is deleterious to
the operation of an irrigation system as well as to the
higher order plants themselves. Growth of slime bacteria
has a propensity to foul the system and clog irrigation
equipment, reducing its efficlency. Likewise, development
of yeast, fungus and algae causes spoiling of plants, and
the fruits and seeds of plants, and otherwise harms higher
order plants. Development of pathogenic microorganisms
such as Verticillium, Pythium, Fusarium, and Pseudomonas in
or on plants also causes various plant diseases. Further
lS more, microorganism development in lLving plants may accel-
erate rotting or spoiling of the plants after harvesting,
or even accelerate rotting or spoiling of fruits or seeds
harvested from the plants. Moreover, development of micro-
organisms in a greenhouse can cover the greenhouse with an
unappealing slime which rubs off on workers who brush
against a coated greenhouse surface, blocks light trans-
mission through the glass walls of the greenhouse, fouls
the greenhouse, makes the greenhouse Eloors slippery, pro-
vide a breeding ground for fungus gnats and other pests,
and potentlally poses health hazards.
Previous attempts to inhibit microorganism
development in plant environments either have failed or
have been self-defeating because ordinary biocides or dis-
infectants, such as bleach or various quaternary ammonium
compounds, that have been employed to kill or inhibit
microorganisms, also are toxic to the higher order plants
in the environment. ThUsl ordinarily the cleaning of
1317217
greenhouse surfaces has entailed tedious, labor intensive
careful scrubbing of the surfaces to avoid accidentally
contacting a plant with the biocide, or time consuming
removal of all the higher order plants from the greenhouse
before washing down the surfaces with a hose. Moreover, it
seems clear that because such biocides are phytotoxic, they
cannot be considered for direct plant treatment either in
the irrigation water to keep clean the surfaces contacted
by the water, or in irrigatlon water or otherwise in order
to treat the plants themselves. On the other hand, how~
ever, while some biocides may have low enough phytotoxic
characteristics to use directly on plants, many have been
associated with health hazards to humans that eat the
plants or harvested parts thereof.
In addition to the health hazards from the toxic-
ity of the oxidizing biocides used in the prior art for
treating microorganism development around plants, such
biocides also usually involve other health hazards from
some other characteristic, such as the explosiveness of
~0 chlorine gas tanks. Other problems with many of the con-
ventional chlorine biocides include instability of the
biocide in the presence of organlc matter, effectiveness o~
the biocide only in a narrow pH range, and the formation of
chloramines in the presence of ammonia, thereby producing
residual compounds which undesireably persist in the
environment. Further, the additives typically employed in
irrigation systems for control of certain microorganisms,
or for other purposes such as fertilization, tend to be
compositions of high water solubility and so require
employment of expensive pumps and other mechanical parts to
regulate the concentration of the additives, to maintain an
appropriate concentration and to avoid a phytotoxic over-
dose.
1 3 1 72 1 7
AS disclosed in Paterson ~.S. patent 3,412,021
and Macchiarolo U.S. patent 4,297,~24, 1-bromo-3-
chloro-5,5-dimethylhydantoin is known as an oxidizing bio-
cide for use in water treatment in certain environments,
such as swimming pools and cooling towers in whlch higher
order plants are not a concern. Patent and other technical
literature discloses a n~mber of uses for this and other
N-halohydantoin compounds based on the biocidal properties
of these compounds.
Summary of the Invention
Among the several objects of the lnvention,
therefore, may be noted the provision of a ~ethod for con-
trolling unwanted microorganisms located on, in or near
higher order plants without harming the higher order
plants; the provLsion of a me~hod for cleaning greenhouses
and surfaces therein with biocide treated water that does
not harm higher order plants; the provlsion of a method for
treating higher order plants for inhibition of unwanted
microorganisms without harming thc hlgher order plants; the
provision of a method for treating higher order plants ~or
controlling disease to the plants without harming the
plants~ the provision of a method for treating higher order
plants for lnhibltion of unwanted microorganisms and con-
trol of disease without harm to the plants and without the
need for extra pumps to apply the treatment; the provision
of a method for treating harvested plants, frults, vegeta-
bles, and seeds for inhibition of rotting or spoi.ling by
treating growing plants; the provision of a method for
irrigating plants whereby development of unwanted micro-
organisms is inhibited; the provision of a method fortreating soil, growth media or aggregate, or hydroponic
solutions for inhibiting unwanted microorganisms without
1 3 1 72 1 7
-5- 6~25-441
harming the plants; the provlsion of a method for treating an
evaporative cooler or humidifier whereby development of unwanted
microorganisms is inhibited; and the provision o~ a method for
trea~ing an evaporative cooler or humidifier whereby development
of unwanted microorganisms is inhibited, and plants contacted by
atomized water emitted from the evaporative cooler or humidifier
are unharmed.
According to one aspect of the present invention there
is provided a method for controlling disease caused by
microorganisms or growth of unwanted microorganisms in or on a
growing higher order plant rooted in a solid growth medium without
harming the plant, the method comprising:
providing ontact between the plant, the rhizosphere of the
plant, or growth medium in which a seed or bulb for the plant is
planted, and a mixture of N-halohydantoin and water, the N-halo
hydantoin being selected from the group consisting o~ a l-bromo-3-
chloro 5,5-dialkylhydantoin and a 1,3-dibromo-S,5-dialkyl-
hydantoin, and being provided in an amount su~ficient to control
said disease or miroorganisms.
~, . . .
1 31 72 1 7
-6- 6~725-~41
According to a further aspect of the present invention
there ls provided a method for treating harvested plants whereby
growth of unwanted microorganisms in or on harvested plants is
controlled without harming the plants, the method comprising
contacting the harvested plants with a mixture of N-halo-
hydantoin and water, the N-halohydantoin being selected from the
group consisting of a 1-bromo-3-chloro-5,5-dialkylhydantoin and a
1,3-dibromo-5,5-dialkylhydantoin, and being pro~ided in an amount
sufficient to inhibit rotting or spoiling of the harvested plants.
The method also controls microorganisms in the root zone
within the growth media. In the method, the higher order plant
remains unbarmed by the N-halohydantoin contained in any of the
treated water that may contact the plant or the growth medium in
which the plant is rooted.
~0,~ .
., ,
1317217
~7- G4725-441
Preferably, the method comprises several steps. First,
N-halohydantoin is dissolved in water to produce a disinfectant
solution having a concen~ration of N-halohydantoin sufficient to
inhibit growth o~ mieroorganisms. Then, growing plants are
contacted with the disinfectant solution. Finally, the yrowing
plants, or
, .~
1317217
their fruit or seeds are harvested and t otting or spoiling
of the harvested plants is inhi.bited.
Description of the Preferred Embodiment
In accordance with the present invention, it has
been discovered that N-halohydantoins, their metabolites
and residuals, can be used for effective control of micro-
organisms in a plant environment without risk of injury to
higher order plants. More particularly it has ben found
that aqueous solutions of N~halohydantoins may be formu-
lated in a wide easily attainable range of concentratlonsthat are high enough to kill various unwanted micro-
organisms such as slime bacteria, yeast, fungus and algae,
yet low enough not to harm higher order plants, whether
contact of the plant with the solution ls intentional or
incidental Regulation of the concentration of N-halohy-
dantoin is simplified by the relatively low solubility o~
these compounds in water, and the fact that the highest
concentration of N-halohydantoin that is obtained under
ordinary conditions is too low to result in phyto~oxicity.
Unexpectedly, not only is a saturated solution of N-halohy-
~dantoin harmless to plants but, astonishingly, actually
seems to stimulate plant growth. It has further been found
that solid state N-halohydantoins are not harmful to hlgher
order plants, and that these biocides may thus be appli.ed
in either solid or solution form in plant environments, or
indeed to the plants thermselves, without risk of injury to
plant systems or tissue.
Moreover, since ingestion of reasonable amounts
of N-halohydantoins is not believed to pose health dangers
to humans from toxicity, ingestion of plants or parts
thereof treated with N-halohydantoin is believed to present
.:'~'';',
-
1317217
no serious or appreciable health risk. FurtheL, .since
N-halohydantoins are nelther flammable nor typically stored
in pressurized containers, they do not present dangers from
explosions The N-halohydantoins of this invention also
show greater stability in the presence of organic matter
and effectiveness over a wider pH range than shown by
typical chlorine disinfectants of the prior art. Further,
the N-halohydantoins of this invention do not tend to form
chloramines in the presence of ammonia, and so are not
believed to form residual compounds which undesirably per-
sist remain in the environment.
Due to the surprising selective toxicity of
aqueous N-halohydantoin compositions, the compositions can
be employed in many biocidal applications wherein the com-
position does or may contact desired higher order plants.Accordingly, greenhouse surfaces susceptible to micro-
organism development may be cleaned with a solution of
N-halohydantoin without undue concern as to whether any of
the solution incidentally contacts the higher order plants
growing in the greenhouse. Moreover, N-halohydantoin can
be incorporated into irrigation water to control the growth
of microorganisms in the water, on the lrrigation equipment
and on surfaces contacted by the water without harming the
plants to be lrrigated.
It has also been found that because o~ the selec-
tive phytotoxicity characteristic, N-halohydantoin can be
incorporated into irrigation water or otherwise applied
directly to plants or to the growth medium in which plants
are rooted to treat the plants, to control microorganism
development in, on and aro~nd the plants and to control
certain plant diseases, without harming the plants. Also
surprisingly, it has been discovered that treating growing
1317217
plants with N~halohydantoin and then harves~ing the plants,
or their fruit or seeds, results in harvested plants, fruit
or seeds that do not rot or spoil as early as do harvested
untreated plants, or ~ruit or seeds from untreated plants.
It further has been found that the benefit of delayed rot-
ting or spoiling also can be achieved by applying N-halohy-
dantoin composition directly to the harvested plants, fruit
and seeds.
In addition, it has been foùnd that the rela-
tively low water solubility of N-halohydantoins avoids the
formation of a highly concentrated phytotoxic solution.
However, the concentration necessary for inhibiting micro-
organism development is so low that the low solubility of
N-halohydantoin does not present a significant obstacle to
production of a solution effective in killing micro-
organisms. In fact, even solutions of low Nvhalohydantoin
concentration have been found to be dramatlcally effective
in killing microorganlsms. Therefore, N-halohydantoin
practically self-regulates for the appropriate concentra-
tion range, and it is essentially unnecessary to provideexpensive pumps and other mechanical parts for introductlon
of N-halohydantoin into a water system, or to introduce the
biocide in a meticulously regulated manner to carefully
control the N-halohydanto5n concentration therein.
It also has been Pound that lncorporating N-halo-
hydantoin in a circulating water system, such as an evapor-
ative cooler or humidifier, located in a greenhouse or
otherwise located in close proximity to desired plants or
other organismsl keeps the system substantially free of
unwanted microorganisms but does not harm the ~esired
plants or other organisms in the environment. Moreover, it
is believed that the atomized treated water propelled from
1317217
~ 64725~~41
the cooler or humidifier and contacting surfaces and plants and
other organisms in the environment improves the sanitation of the
environment.
Preferably, the N-halohydantoin of this invention is an
N,N'-dihalohydantoin compound, more particularly a l,3-
dihalohydantoln corresponding to the formula:
X~
2R~N~
o~ X , . ._
wherein Rl and R2 are independently alkyl, and Xl is bromo and x2
is bromo or chloro, R1 and/or R2 may for example, comprise methyl,
ethyl, n-propyl, isopropyl, n-butyl, or n-pentyl. Generally, it
is preferred that the constituents comprising R1 and/or ~2 contain
not more than about 5 carbon atoms. Preferred N-halohydantoins
are N-halogenated dimethylhydantoins. Particularly preferred N-
halohydantolns include 1,3-dibromo-5,5-dlmethylhydantoin and 1-
bromo-3-chloro-5,5-dimethylhydantoin.
In this invention, N-halohydantoin is incorporated in
water to produce an oxidizing biocide composition. The
concentration of N-halohydantoin in the composition as it is
applied to inhibit microorganism development or to control plant
disease .should be at least about one part per million, and
preferably at least about 5 ppm, to be effective against
microorganisms and related diseases. However,
~ . , .
-
1317217
the concentration of N-halohydantoin in the composition as
the composition contacts desired higher order plants should
not exceed the point at which the composition becomes
phytotoxic. Nevertheless, it has been found that the con-
centration of N-halohydantoin, due to its low solubility,
under ordinary conditions, does not exceed about 1500 ppm,
at which concentration not only has phytotoxicity not been
observed, but the growth of higher order plants seems to be
stimulated Thus, a biocide of N-halohydantoin concentra-
tion between about 1 and about 1500 ppm has been foundeffective to kill unwanted microorganisms, yet harmless to
higher order plants.
~ he N-halohydantoin may be incorporated into a
water system at any point in the system although, of
lS course, for a non-recirculating system the biocidal activ-
ity resulting from the N-halohydantoin only occurs down-
stream of the point of incorporation. Moreover, as noted,
due to the self-regulatory nature of the N-halohydantoin
dissolution, special pumps and other mechanical parts for
metering the N-halohydantoin are unnecessary, and so the
incorporation of the N-halohydantion in water can be an
essentially passive operation.
Thus, for example, solid N-halohydantoin, prefer-
ably in particulate form, can be placed in a mesh bag and
suspended in a stream of water or in a well of a water
circulating system. Water contacting the N-halohydantoin
in the bag dissolves some of the N-halohydantoin. For a
stream the relationship between flow rate and effectiv
area of contact between water and solid biocide should be
such that the downstream N-halohydantoin concentration is
at least 1 ppm. As noted, due to the relatively low water
solubility of N-halohydantoins, the concentration of
1 3 1 72 1 7
13
N-halohydantoin under ordinary conditions remalns less than
about 1500 ppm. Ordinarily, the concentratlon remains
between 2 ppm and 10 ppm. Preferrably the concentration is
between about 5 ppm and about 10 ppm. Accordingly, by this
essentially passive mechanism, the treated watee contains a
concentration of N-halohydantoin sufficient to control
development of microorganisms and plant disease without
harming higher order plants.
On the other hand, if so desired, N-halohydantoin
may be introduced into the water by means of an inexpensive
standard halogenator or brominator. If a brominator is
used, either the entire water stream is directed through
the brominator, or a side stream is diverted, passed
through the brominator and reunited with the main stream.
Likewise, for applications of N-halohydantoin by hose, a
brominator may be connected to the hose line or N-halohy-
dantoin may be placed in a hose attachment such as those
originally intended for application of detergents and
cleaning compounds.
There are several applications for the water so
treated with N-halohydantoin. For example, the treated
water can be applied to an irrigation system to clean the
irrigation equipment and other surfaces, to clean or to
treat the plants and the fruit and seeds they bear, to
treat by foliar application the plants and the ~ruit and
seeds the plants bear, to clean a greenhouse without harm-
ing plants therein and to treat and to clean evaporative
coolers or humidifiers often found in a greenhouse.
In a greenhouse, plants are often watered by
means of a capillary mat irrigation system. In a capillary
mat irrigation system, irrigation water typically is
1317217
14
delivered through a conduit to a water absorbent sheet of
material, such as polypropylene felt. ~y means of the
natural absorbency of the material, the water is trans-
ported through the material to the growth medium of potted
plants sitting on the absorbent material.
N-halohydantoin may be introduced into a green-
house irrigation system by directing the stream of water to
be used for irrigation through a brominator containing
N-halohydantoin, The biocidal activity of the treated
water not only tends to prevent development of unwanted
microorganisms that otherwise proliferate in the water and
on the irrigation equipment, but also prevents the develop-
ment of microorganisms that otherwise grow and coat the
irrigation mat and the pots holding the plants. Thus, by
including N-halohydantoin in the system, clogging of the
irrigation equipment and coating of the irrigation mat are
avoided, and the efficiency degradation normally encoun-
tered with the irrigation system is suppressed. Also
extends the useful life of the equipment. Further, such
treatment of the irrigation water also inhibits development
of microorganisms on the floor and other surfaces in the
greenhouse often contacted by irrigation water run-off.
As for the plants themselves, the cleaner water
provided by this method is believed to deliver to the
plants via the roots thereof fewer living microor~anisms
that could be deleterious to the plant~ Moreover, the
biocidal activity of the treated water delivered to the
plant is believed to inhibit microorganism development in
and on the plant, and so helps prevent or control certain
plant diseases which could result from pathogenic micro-
organisms. Importantly, therefore, this method is believed
to control diseases that otherwise spread quickly through
1317217
the plants in a greenhouse. Also prevents spread of
disease by re-cycled greenhouse irrigatlon water. Yet,
despite such biocidal activity of water treated with .
N-halohydantoin, the plant itself .is not harmed by the
treated water. Thus, irri~ation water can be treated wlth
N-halohydantoin for all these purposes, to avoid Eouli.ng
and clogging of the equipment and other surfaces and to
treat the irrigated plants, without endangering the plant.
Walls, ceilings and floors in greenhouses, and
even filters from evaporative coolers may be cleaned in
accordance with this invention by hosing down the surfaces
with treated water. The biocidally treated water kills the
algae and other microorganisms that develop on the surfaces
and cleans far more effectively than does untreated water,
but treated water that splashes onto the plants in the
greenhouses does not harm the plants as do other biocides
such as bleach. Therefore very time consuming removal of
plants from the greenhouse before cleani.ng is unnecessary.
For this application, the water can be treated by dissolv-
ing N-halohydantoin in a volume of water, by inserting
N-halohydantoin in the water stream, or by directing the
stream, or a side stream, through a brominator contai.ni.ng
~-halohydantoin. The greenhouse may then be quickly and
easily hosed down without serious danger of harming the
plants hit by splashed water, deflected water, extraneous
atomized sprays of water, or even misdirected streams of
water.
By the method of this invention, evaporative
coolers or humidifiers, whether located in a greenhouse or
another environment containing ~lants, animals, or other
organisms also can be maintai.ned substantially free o~
fouling microorganisms without harming plants or animals
1~17217
16
nearby. As with the other particular applications,
N-halohydantoin can by incorporated at essentially any
point in the system. ~dvantageously, N-halohydantoin can
be placed in a mesh bag in the water collecting well o~ the
circulating system. The self-regulating mechanism of
N-halohydantoin discussed above tends to maintain the
treated water at an appropriate concentration. In accord-
ance with this method, the evaporative pad remains sub-
stantially free of unwanted microorganisms that otherwise
accumulate, while equipment, plants or other organisms
contacted by atomized treated water drifting from the
cooler or humidifier not only are not harmed by the treated
water, but may be disinfected by the treated waterO Thus,
an unhealthy environment can be converted to a healthful,
somewhat antiseptic environment.
As with greenhouse plants, crops or plants in an
outdoor nursery may be irrigated with treated water.
N-halohydantoin may be incorporated anywhere in the water
system as described above, and the plants irrigated with
the treated water by any of several irrigation methods,
such as spray irxigation, trickle or drip irriga~ion, mist
or fog irrigation, sub-irrigation, ebb-and-flow irrigation,
and hydroponics. Also as with the greenhouse irrigation
methods, the treated water acts to control unwanted micro-
organisms Prom developing on the irrigation equipment, aswell as in or on the plants and growth medium in which the
plants are rooted. The treatment thereby helps prevent
certain plant diseases arising from pathogenic micro-
organisms and control the outbreak and spread o~ such
diseases.
In an alternative application of the method of
the invention, solid N-halohydantoin may be placed on or in
- .
1317217
17
the ground near growing plants so that rain or irrigation
water delivers the N-halohydantoin to the plant's roots or
rhizosphere. Likewise, solid N-halohydantoin may be placed
on or in the ground near implanted bulbs or seeds so that
rain or irrigation water delivers the N-halohydantoin to
the roots or rhizosphere of plants grown from the bulbs or
seeds. Or, if desired, the bulbs or seeds themselves may
- be treated by applying powder or granular N-halohydantoin
or a slurry or solution of N-halohydantoin directly to the
bulbs or seeds before planting.
In still another alternative embodiment of the
application of the method of this invention growing plants
may be treated with the treated water or by foliar applica-
tion of an N-halohydantoin powder, slurry or solution to
lS inhibit the development of unwanted microorganisms and
diseases on or in the fruit or seeds of the treated plants,
and to delay rotting or spoiling of the plants, fruit or
seeds even after harvesting. Significantly, the treatment
process of this invention not only is harmless to the
plants, but because ingestion of N-halohydantoins in
ordinary doses is widely believed to be safe to humans,
unlike many presently available herbicides and pesticides,
the resulting low doses of N-halohydantoin in ~he harvested
plants, fruits and seeds appear to pose no appreciable
health hazards to humans consuming them.
Due to the self-regulating quality, N-halohydan-
toin can also be applied to growing plants by placing solid
N-halohydantoin on or in the ground near the rhizosphere o
plants, and rain water or irrigation water will dissolve
the N-halohydantoin to the plants in appropriate dosages.
If desired, the N-halohydantoin can be applied to ~he
ground before germination of seeds or growth o bulbs, and
1317217
18
can even be applied to the ground while planting seeds or
bulbs, thereby eliminating the need for a separate treat-
ment step. Optionally, or in the alternative, N-halohydan-
toin can be added as a powder or slurry di~ectly to bulbs
or seeds before planting. It is believed that these appli-
cations of N-halohydantoin directly to the growth medium or
the bulb or seed itself and transportation to the plant by
rain or irrigation water is effective in controlling
development of unwanted microorganisms and plant diseases
without harming higher order plants.
Alternatively, or additionally, N-halohydantoin
can be applied topically to plants, fruit o~ seeds after
harvesting. The N-halohydantoin can be dissolved in water
to form a treatment solution. Then, the harvested plants,
~ruit or seeds can be sprayed or washed with the treatment
solution. Or, if so desired, the harvested plants, fruit
or seeds can be dusted or coated with N-halohydantoin
powder or an N-halohydantoin slurry. Regardless, the
harvested plants, fruit and seeds are not harmed nor are
~0 they believed toxic to humans. Yet, microorganism develop-
ment in and on the harvested plants, fruit and seeds is
inhibLted and so rotting and spoiling is delayed.
Thus, N-halohydantoin can be applied in conjunc-
tion with irrigation, applied as a separate treatment or
incorporated in water used for other purposes to protect
plants unintentionally hit by the water.
Other advantages derived from the practice of
this invention will become apparent from the following
description and examples:
1 31 72 1 7
lg
EXAMPLE_l
Experiments were conducted to compare the e~Eec-
tiveness of an N-halohydantoin composition wlth the effec-
tiveness of sodium hypochlorite in producing deslred levels
of free residual halogen in infested water. A bromo-
chloro-dimethylhydantoin ~BCDMH) solution wa~ callbrated so
that five drops o the solution added to distilled water
~300 ml) resulted in a solution of 1 ppm BCDMH. Water
samples were collected from a muddy water seepage area in a
canal slte. A second set of water samples was collected
from a "swamp" at the bottom of an 800-foot well. The
swamp water contained 0.5 ppm hydrogen sulfide, 0.8 ppm
iron, S ppm aromatic hydroxyl compounds and probably other
unknown impurities. Drops of the BCDMH solution were added
to the water samples (300 ml each) and the free residual
bromine in the sample measured to determine the BCDMH con-
centration necessary to produce 0.6 ppm free residual Br-
in the sample. The results were compared to the sodium
hypochlorite concentration necessary to produce 0.6 ppm
free residual Cl- in the sample. The Cl- concentratlon
was measured with a standard Hach test kit. The Br~
concentration was measured with a similar test kit, The
results were as follows:
Canal Water Swamp Water
25 Total NaOCl Added5.6 ppm 4.2 ppm
Free ~esidual Cl- 0.6 ppm 0,6 ppm
Total BCDMH Added- 4.0 ppm 3,4 ppm
Free Residual Br~006 ppm 0.6 ppm
Thus, about 23~ to 40~ more sodium hypochlorite than ~CDMH
was required to produce the same level of free residual
halogen.
-
1317217
EXAMPLE 2
Chrysanthemums and gladioli were planted ln ~our
50-~oot plots under ull-bed culture in ~auGallie fine
sand. ~he plants were irrigated by drip irrigation. One
week later, BCDMH was introduced into the irrigation water
of two of the 50-foot plots. The BCDMH was introduced to
the irrigation water by mixing 9~ a~ueous BCDMH mixture (71
gal.) with water (4000 gal ). The 4071 gallons of total
solution were applied to the two 50-foot plots (about 11
acre inches of irrigation) over almost ten weeks. Residual
Br~ concentration in the water collected from the end Oe
the drip tube during operation was 2 to 2 5 ppm. The
following results, showing no adverse effect on either
chrysanthemum or gladiolus production, were obtained:
Chrysanthemums:
Weight/Plant (lbs.) No. of Plants
Untreated Plot 3.6 100
Treated Plot 3.8 100
Gladiolus:
No of Stems No o~ Florets
Per Stem
~ntreated Plot 55 14.2
Treated Plot 49 14.6
No significant difference in microorganism development was
apparent between the tubes carrying treated water and those
carrying untreated water, but it is believed that the dura-
tion of the trial was too short for any significant differ-
ence to appear.
1317217
~XAMPLE 3
Two sets of Yellow Mandalay chrysanthemums
(thirty plants per set) were grown and irrigated by sub-
irrigation mats. The plants were fertilized with six
S ounces of Osmocote per cubic foot of growing medium. One
set of plants (control) was not treated with biocide. For
the other set of plants ~test), BCDMH was injected into the
irrigation system at a rate of about 2 to 4 ppm. ~romine
levels of the test and control mats were measured daily and
the bromine level was maintain 2 to 4 ppm higher than the
level of the control. About eleven weeks after planting,
leaf samples were collected and analyzed. Table 1 shows
; levels (in percent by weight) of various nutrients (nutri-
ents for which the fertilizer was the only direct supply)
lS found in the leaves (and compared with desired levels):
While the test samples showed lower concentra-
tions of some nutrients, the experiments were not conducted
~or such analysis and fertilization was not controlled.
Thus, these results are not believed signFicant in dis-
tinguishing the effects of BCDMH on nutrient uptake. Theplants were then evaluated for phytotoxicity. There was no
observable phytotoxicity. The plant heights were measured,
but no difference was observed between the heights or
growth between the treated plants and the control plants.
While considerable algae growth had developed on
the mat and fungus gnats had become a problem in the con-
trol set, there was no algae growth on the treated mat.
Three weeks later, algae growth still had not appeared on
the treated mat.
1317217
22
The experiment was repeated with exacum lnstead
oE chrysanthemums. T~ble 2 shows results from the foliar
analysi.s were obtained:
1317217
23
N 1--
æl~ N Z1~
~1~ ~ I ~lo ~ I
¦~) N ~ ¦~ N
t` ~D
~ + ~ ' +
clco ~ O ~ o o
~--~D 0 1-- ~ O
'1 . '1 ~
V 1~
~D
o ~ o a~ ~- o
m N _~1 m ~ ~
~ ~ . +
~l~ ul o c~l~ N O
~ + ~ +
~clr-. o oN ~¦~`1 ~
::1~ N ~ ~ I N ~`
m~r~ m~o
~~ ~ ~~ ~ )
E~ :~ . . E~ ~ .
o O o o o o
U- ~
o o ,~ r- o~ o
~ . . . ~ . . .
N ~ _ O O ~1
~ a~
--~D O N 0~ 0
. . . ~ . ~
r ~ o ~r
~) ~`J 0 1--
N ~1 ~ ~ ~1 r
. . . ~ . . .
ooo ooo
N N ~ ~
~ ~ U~ f~) N U'l
z ~."~ æ ~r
o ~ o ~ -
C ~ U~
o ~ ~ o
o
U~
1317217
2~
While the test samples showed lower concentrations of sorne
nutrients, the experiments were not conducted for such
analysis and fertllization was not controlled. Thus, these
results are not believed signficant in distlnguishing the
effects of BCDMH on nutrient uptake. Moreover, with ~he
exacum it was noticed that of the 80 plants on the control
mat, 50 had roots growing into the mat. Of the remaining
30 plants, many had roots growing out of the pot, but not
yet into the mat. However, of the 77 plants on the treated
mat, none "stuck" to the mat or had roots growing out of
the bottom of the pot. Thls avoidance of sticking to the
mat is desirable for aesthetics and ease of handling.
EXAMPLE_4
The following plants received a drench of foliar
applicatlon of a saturated (1500 ppm) BÇDMH solution:
Foliage Croe Potted Plants
Pilea Grape Ivy
Syngonium Zebra Plant
Schefflera Velvet Plant
Pepperomia English Ivy
Dieffenbachia Christmas Cactus
Ficus Benjamina Asparagus Fern
Neanthe ~ella Perrywinkle
Maranta Leuconeura Fibrous Begonia
Coleous
r mpatiens
Applications were intermittent for three to six weeks in a
greenhouse environment, No phytotoxicity was observed In
a separate experiment, the same types of plants received
foliar sprays containing 150Q ppm BCDMH. Plants received 3
applications of spray separated by lO day intervals. No
phytotoxLcity was observed.
-
1 3 ~ 72 1 7
The following plants were sprayed with BCDMH
solutions of 1, 10, 100 and 1000 ppm in the spring:
Potted Plants Flats
8" Zonal Geranlum Fibrous Begonia
3" Tomatoes Seed Geranium
6" Pot Mums Non-Stop Begonias
4" Gebera Petunias
Impatiens
Excep~ for occasional pinpoint burns on some flowers
sprayed with the most concen~rated solution, no other signs
of phytotoxicity were observed. Undissolved particles of
3CDMH are believed to have caused the pinpoint ~urns.
Unopened buds were not ha~med.
The following plants in 4-inch pots were sprayed
15 with BCDMH solutions of 1, 10, 100 and 1000 ppm in the
summer:
Potted Plants
Pteris Cretica
Gloxinia
20 African Violet
Gerbera
Non-Stop Begonia
~ild phytotoxicity symptoms were observed on open flowers
at 100 and }000 ppm.
EXAMPLE 5
Seeds were planted in several plots. several
sets of seeds were coated with various powder composi-
tions. Some of the compositions comprised the commercially
available products phygon, the dichlone 2,3-dichloro-
1~4-naphthoquinonel w~ ch is a trade designa~ion o~
Uniroya ~ and Vitavax, a carboxin, which is a trade desig-
nation of Uniroyal. The formulas of these products are not
~ ~rt~C~e- ~at`k
t317217
26
known. One set of seeds in each plot were uncoated. The
coatings for each set and the amounts of the coatlng (in
ounces per hundred weigh~) were as follows:
Set Coating CompositionAmount of Coatin~
1 none
2 Pentacbloronitrobenzene12
! ~ 3 Phygon~27X 12
.,`. ~ 4 Phygon 27X and Vitavax 30C 10 and 3.3, resp,
5 Phygon 27 and Vitavax 30C 10 and 3.3, res~.
6 Phygon 29 and Vitavax 30C 10 and 3.3, resp.
7 Phygon 27 7
8 Phygon 27 and Vitavax 30C 7 and 3.3, resp.
9 Phygon 29 7
10 Phygon 29 and Vitavax 30C 7 and 3.3, resp.
11 Particulate 92.5~ BCDMH 5
12 Particulate 92.5~ BCDMH10
The seeds were planted in various plots, with the
following survival rates ~in percent of planted seeds that
survived) of the seeds (sets 11 and 12 were planted only in
20 plot 3):
Plots:
Set 1 2 3 4 5 G
1 83 34 43 77 25 59
2 76 31 58 77 28 61
3 81 34 63 79 26 6~
4 82 26 69 73 48 63
83 30 60 79 39 63
6 82 ~1 55 8~ 43 65
7 78 33 41 80 - 58
8 ~2 39 58 81 -- ~5
9 80 37 46 77 -- 60
83 32 60 81 -- 64
11__ __ 47 _~
~ 58
35 Minimum significant
differences:5 -- 11 -- 11 -
The minimum significant difference indicates the
95~ confidence ran~e within which there is no significant
difference. For example, for the survival rate of set 12
~ ~rQde~m~k
. ~ .. ;.. . . ... . . .
1317217
(58~), there is no significant difference between survival
rates between 47% and 69%. Thus, it appears from the data
that the BCD~H seed coating is at least as effective as the
other coatings~
In view of the above, it will be seen that the
several objects of the invention are achieved and other
advantageous results attained.
