Paddy rice treatment

A method of treatment of a paddy whereby a plant protecting effective amount of a plant protecting composition, with the water soluble envelope containing it, is dropped in different locus of the water of a paddy where the rice plants are growing, this plant protecting composition being in a viscous or sticky fluid form, such as a liquid or a gel, which is able to spread rapidly and uniformly along the surface of the water of the paddy and coat the rice plant of insect in response to changes in the water level.

BACKGROUND OF THE INVENTION 
I. Field of the Invention 
The invention relates to new methods for treatment of paddy rice. More 
specifically, it relates to a method of treating paddy rice, wherein a 
water soluble package containing a viscous or sticky fluid or gel plant 
protecting agent is placed in the rice paddy such that the agent spreads 
to form a uniform film, which can coat the rice plants in response to 
water levels changes in the rice paddy. 
II. Discussion of the Related Art 
It is well known that paddy rice, as well as most other crops in the world, 
is commonly infested with many pests, such as insects and weeds. 
There are many difficulties in treating paddies in order to control weeds 
or insects because of the unusual wetland growing conditions used to raise 
paddy rice in addition to those difficulties found with most crops. 
First of all, there are the classical problems of all pesticidal 
compositions having a pesticidal active ingredient. These products should 
be applied to the crops in a safe manner and need to be applied in a 
timely and efficient manner for the composition to have its greatest 
effect. 
The application of an effective amount of these products in a safe manner 
on crops means that an effective amount of active ingredient is provided 
to the plant while a minimum amount of the said active ingredient is 
applied or remains elsewhere, either in the environment, on the 
application tools or machinery, or onto the persons who are handling these 
products. A safe manner to apply the active ingredient includes reduced 
worker exposure to these products, safety for the environment, including 
spills, and minimized container disposal issues. 
The application of these products in an efficient manner means that an 
effective amount of active ingredient is provided to the plant which needs 
it, in order to save it from the pests. That is to say, the amount of 
insecticides afforded to the plant should be large enough to kill the 
insects attacking or going to attack the plant during a substantial time 
frame. It also means the amount of herbicides afforded to the plant should 
be large enough to kill the weeds or to slow down or prohibit the growth 
of weeds competing with the crop, and this effect should remain during a 
substantial time frame. Still another requirement is that a uniform or 
balanced amount of active ingredient should be applied to the plants in 
order that phytotoxicity and efficacy are well coordinated. 
Regarding the paddies, one common method of applying pesticides is to 
introduce the mixture on the water of the paddy, so that the active 
ingredient is spread out and dispersed on the surface of the water, and 
reaches the rice plant so as to have its efficacy directly on the plant at 
the interface of the water surface and plant. 
Rice paddies are fields that can be flooded with water and usually bordered 
by an elevated dry area or other such edge area. In order to have the 
active ingredient spread out in a uniform manner, the most practical 
manner currently used is where the farmer, walks through the flooded area 
of the paddy, with his feet immersed in water, as he introduces the active 
ingredient in the water near him. Unfortunately and obviously, a major 
drawback of this method is to have the farmer, through his feet, 
permanently in contact with a liquid (the water of the paddy) containing 
the pesticide. 
One solution to the above problems is described in Japanese Patent No. 
563-30281 to Nihon Kayaku K.K., published Jul. 29, 1985 and granted on 
Jun. 17, 1988. The method described in this patent involves use of a 
powder and dry granules of active ingredient in water soluble packaging. 
The granules initially sink to the bottom then eventually float on the 
surface and dissolve in the water. While they avoid the need to walk in 
the flooded area, granules deliver active at other than the surface, are 
relatively slow to dissolve and disperse on the surface of the water, are 
expensive to make and still represent a dusting problem during 
manufacture, do not coat the surface of the water evenly and may only 
afford protection at the interface between the film on the water surface 
and the plant and do not coat the plant under changing water levels in the 
rice paddy. 
There are many methods of treatment of paddy by all kind of agrochemicals, 
either liquid or solid, but there is a need to find better methods to 
increase simultaneously the safety for people who are handling the active 
ingredient and the efficacy of the active ingredient for the plant, i.e. 
rice plant. 
SUMMARY OF THE INVENTION 
An object of the instant invention is to provide a new and safe method of 
treatment of paddies against pests. 
Another object of the instant invention is to provide a new method of 
treatment for paddies which is simultaneously safe for the workers and 
efficient for the crop. 
Another object of the instant invention is to provide an inexpensive and 
easy method of treatment for rice paddies. 
Other objects of the instant invention will better appear in the 
description which follows. 
Another object of the instant invention is to provide a safe and easy 
method to protect paddies against insecticidal attacks, said method being 
better able, not only to spread on the surface of water of paddies, but 
also to join or coat the stems of plants and the insects walking thereon 
or going to walk thereon. 
Another object of the instant invention is to provide a safe and easy 
method to protect paddies against insecticidal attacks, said method being 
better able, not only to spread on the surface of water of paddies, and to 
join the stems of plants but also to remain on or to coat to such stems. 
Another object of the instant invention is to provide a safe and easy 
method to protect paddies against insecticidal attacks, said method being 
better able, not only to spread on the surface of water of paddies and to 
join or coat the insects walking on or going to walk on the stems of 
plants, but also to remain on or to coat such insects. 
Another object of the instant invention is to provide a safe and easy 
method to protect paddies against insecticidal attacks, said method being 
better able to form less waste water, especially less waste water 
containing insecticides. 
Another object of the instant invention is to provide a safe and easy 
method to protect paddies against insecticidal attacks, said method being 
better able to lose less insecticides in the water of paddies. 
It has been found that one or more of these objects can be met by the 
method of treatment of paddy of the instant invention. 
The invention provides a new method of treatment of a rice paddy whereby a 
plant protecting composition in a water soluble envelope is dropped onto a 
paddy where the rice plants are growing or will grow, this plant 
protecting composition being a viscous or sticky fluid or gel and able to 
spread rapidly and uniformly along the surface of the water of the paddy 
and coat the rice plants in response to changes in water level. 
According to a preferred feature of the invention, a gel composition is 
used. 
According to another feature of the invention, the size of the bag and the 
concentration of active ingredient (plant protecting) is determined so as 
to be able to protect an area large enough so that there is no need to 
walk through the field to treat it. 
DETAILED DESCRIPTION OF THE INVENTION 
More precisely, the invention provides a new method of treatment of a paddy 
utilizing an effective amount of a plant protecting composition, with the 
water soluble envelope containing it, the method comprising positioning in 
different loci of the water of a paddy where the rice plants are growing, 
the plant protecting composition being in the form of a viscous or 
sticking fluid or gel, which is able to spread rapidly and uniformly along 
the surface of the water of the paddy and coat the rice plant when the 
water level is lowered or raised in the field. 
By positioning, it is meant to drop, throw, place or the like in the water 
from a position outside the water, preferably the dry bank. 
By plant protecting composition, it is meant a composition comprising an 
active ingredient which may have a plant protection action, such as a 
plant growth regulator, herbicide, a pesticide or the like. This pesticide 
may be an insecticide or a fungicide or a nematicide or a miticide or a 
molluscicide. Herbicides are considered as plant protecting in the sense 
that they protect the crop by killing the weeds. 
By viscous liquid or gel is meant a liquid plant protection composition 
having a Brookfield viscosity sufficient such that the viscosity aids the 
active in coating the plant on response to water level changes. This would 
be around at least 200 cps up to as much as 50,000 cps but will vary from 
compound to compound. By sticky it is meant that composition which 
contains, or is itself a sticker, that is the plant protecting composition 
will adhere or coat the plant in response to changes in water level. This 
is normally accomplished by choosing a liquid solvent which has a higher 
affinity for organic materials than for water. Once the liquid or gel has 
formed a film on the surface of the water, changes in the level of water 
will cause the liquid or gel to coat the rice plants. This coating will 
give protection from insects which actually exists or move about on the 
plant and come in contact with the coating by walking or landing thereon. 
Although all plant protecting agents are contemplated in this invention, 
nevertheless, insecticides and insecticidal compositions are especially 
appropriate and beneficial for rice growers. Thus the method of the 
invention is especially effective against insects which are moving or 
traveling along the stem of the plant, up and down, such as the rice water 
weevil, rice stem borer, grass leaf roller, rice leaf beetle, brown plant 
hopper and the like. 
The plant protecting composition in the water soluble envelope is called 
hereafter a plant protecting unit. 
The water soluble envelope may be of any type of enveloping system. 
Preferably it is a bag. 
The envelope is generally made of a water soluble polymeric material in the 
form of a film, and this film constitutes the wall of the bag. Polymeric 
material which can be used in the invention are polyvinyl alcohol; 
cellulosic materials such as methyl or ethyl cellulose; polyalkylene 
oxides. A preferred material is the polyvinyl alcohol, which is 
advantageously totally or partially hydrolyzed or alcoholyzed polyvinyl 
acetate. The hydrolysis or alcoholysis rate of polyvinyl acetate in the 
invention is generally between about 70 and about 99% (new co-polymers get 
close to 100% hydrolysis. All these materials should be cold water soluble 
(cold means, here, less than 35.degree. C.). 
The thickness of the wall of the envelope can be great enough so that it 
dissolves in the water of the paddy at the desired rate. Thus the 
thickness is generally comprised between 1 mm and 10 micrometer. 
Preferably, the thickness is in the range from 10 to 150 micrometer. As 
newer films get developed, strength may be improved to go to thinner 
films. It will be desirable to use the thinnest film possible. 
In order to protect the whole paddy which is to be treated, more than one 
envelope may be dropped into the paddy water. They are dropped in 
different loci so that the different surfaces which are reached by the 
spreading of the composition contained in one envelope are joined and 
formed to cover the surface of the whole paddy with as little overlap as 
possible. Much of this can be accomplished by making the envelope of a 
size such that the amount of active ingredient is appropriate for the 
paddy size. 
In order to have the plant protecting composition spreading rapidly and 
uniformly and/or coating adhering or sticking or acting on the stems, 
further various modes of practicing the invention have also being found. 
According to another feature of the instant invention, a method of 
treatment of paddy, as already presented, comprises further the use of a 
plant protecting composition which has one or more of the following 
characteristics. 
The active ingredient, that is to say the plant protecting agent, 
preferably has a low water solubility. Generally solubility is less than 
5% (w/w) , and a solubility less than 2% is preferred. It is preferred 
that the active ingredient has a better solubility in the solvent of the 
composition than in water, so that it prefers to spread with the 
composition on the water rather than in the water towards the ground. 
Generally, the ratio of solubility in the solvent/solubility in water is 
more than 5, preferably more than 10. It is preferred that the active 
ingredient, that is to say the plant protecting agent, is in a solubilized 
or dispersed form. The plant protection composition is enclosed in a water 
soluble envelope, or preferably a bag, which is preferably able to float 
on the surface of the water. 
It is especially preferred that in order for the plant protecting 
composition to form a film, it must float on water. Its specific gravity 
is thus preferably less than 1 g/cm.sup.3, and still more preferably in 
the range from 0.7 to 0.98 g/cm.sup.3. Specific gravity can be &gt;1 and 
sink, but the material inside bag should eventually float to the surface. 
The composition can also include, as an aid to the spreading, a water 
immiscible solvent having a specific gravity less than the specific 
gravity of the water of the paddy (that means generally less than 1 
g/cm.sup.3). It can also comprise a cosolvent; the purpose of this 
cosolvent is generally to adapt the solubility and dispensability of the 
active ingredient in the solvent; some solvents like vegetable oils might 
be chosen for other beneficial properties they have and not have the best 
solubilizing or wetting ability; the cosolvent is the remedy to this 
problem. 
One other optional ingredient for the plant protecting composition 
comprises a highly surface active agent. The surface active agent of the 
plant protecting composition is mainly a wetting agent having spreading 
properties (wetting/spreader). In order to assess whether a wetting 
spreader is suitable according to the invention, the following test is 
carried out: 1-2 drops of material in 31/2 inch dish of water and looked 
to see what spread the best. 
The plant protecting composition optionally comprises a sticker to adhere 
the active ingredient to the rice plant; a sticker is a material that 
helps adhere or coat the active ingredient to plant stem in a rice paddy 
having an affinity for organics relatively higher than that of water; 
vegetable oils which may be used as solvents are also appropriate 
stickers, especially cottonseed oil, soybean seed oil, corn oil, rapeseed 
oil, sunflower seed oil, coconut oil; hydrocarbons such as terpenes, 
pinene are also suitable. Hydrocarbons that are useful are those which are 
insoluble in water (&lt;2% by weight), are compatible or can be made 
compatible with the pesticidally active ingredient, and can have their 
surface tension lowered (i.e., this causes rapid spreading on the water 
surface) by the addition of a surface active agent. The hydrocarbon 
solvent should have a density of a 1 g/cc so that it will float on the 
surface of the water rather than sink and be diluted by the water in the 
rice paddy. Terpenes are useful hydrocarbon sticking agents for once they 
adhere to a surface, they tend to react with the sunlight and polymerize 
on the surface of the plant which makes it more difficult for it to be 
washed off as the height of the paddy changes throughout the season. 
The size of one bag or envelope, amounts and concentrations of ingredients 
in the composition contained in the bag or envelope are chosen so as to 
fit to an area of 100 square meter (plus or minus 10% of paddy field, 
The preferred size of bags used to contain the liquid or gel is in the 
range of 10 to 1500 ml, most preferably in the range of 10 to 500 mi. 
There may be needs to go bigger on sloping fields where bags are placed at 
the top of the field. 
According to another feature of the instant invention, better adhesion of 
the plant protecting agent and composition is obtained when the flooded 
field is adjusted either artificially or by natural means such as 
evaporation. Thus, the invention is also directed to a method of treatment 
of a paddy as already defined which comprises a further optional step 
(after dropping the envelopes in the paddy and alley, the composition to 
spread on the surface) of lowering the water level in the paddy. 
A particular feature of the invention is a method as already described 
whereby one water soluble envelope containing a plant protecting 
composition is dropped or thrown into a sector of the flooded paddy field, 
the said sector, with the other similar sectors, constituting the whole 
flooded paddy field. For example, it is particularly convenient and 
efficient to walk around the paddy field on the dry areas and to drop one 
envelope per square sector on a rectangular paddy field, two sectors being 
as long as the paddy field is wide. 
Another preferred feature of the instant invention is a method which 
comprises application of plant protecting unit wherein the plant 
protecting composition is not flowing through pinholes and such as its 
Tg(phi) (as hereafter defined) is less than or equal to 1.5, for example 
through use of a gel. 
Many types of insecticides may be used in the invention, for example 
carbaryl, Thiodicarb, Ebufos, Carbosulfan, Amitraz, Vamidothion, Ethion, 
Triazophos, Propoxur, Phosalone, Parathion, Methylparathion, Diazinon, 
Malathion, Lindane, Fenvalerate, Ethoprophos, Endrin, Endosulfan, 
Dimethoate, Dieldrin, Dicrotophos, Dichlorprop, Dichlorvos, Azinphos and 
its Derivatives, Aldrin, Disulfoton, Chlordimeform, Chlorpyrifos, Dicofol, 
Propargite, Demeton, Fipronil. 
Herbicides, Fungicides or Plant growth Regulators may also be used. For 
example herbicides such as oxidiazon, anilofos, piperophos, esprocarb, 
benthiocarb, dimepiperate, molinate, pyributicarb, daimuron, butachlor, 
pretialchlor, butenochlor, terbuchlor, benzofenap, MCPCA (mapica) 
clomeprop, inabenfide, furyloxyfen, pyrazolynate, propanil, carbendazim, 
and fungicides such as triapenthenol, uniconazole, probenazole, 
validamycin, isoprothiolane, ediphenphos, tricyclazole, and iprobenfos. 
Solvents which can be used in the invention are preferably liquid at room 
temperature (but, high temperature liquids may also be useful) and not 
miscible with water. They may be used as a single solvent or a mixture of 
solvents. Solvents which may be used include xylene, toluene, liquid alkyl 
substituted aromatic hydrocarbon; alkyl or alkenyl esters of aliphatic or 
aromatic acids, such as benzoates, salicylates or anthranilates, 
especially esters having 1 to 8 carbon atoms in the alcoholic part of the 
molecule and 6 to 18 carbon atoms in the acid part of the molecule; alkyl 
or aryl ethers; cyclohexanone vegetable oils such as cottonseed oil, 
soybean oil, corn off, rapeseed oil, coconut off, sunflower seed oil, 
olive oil, palm off, peanut off, safflower off, sesame off, rice bran off; 
esters derived from vegetable oils; vegetable oils are preferred as more 
environmentally friendly. 
Cosolvents which may be used in the invention include ketones, like 
cyclohexanones; lactones like butyrolactone; amides; N-alkyl pyrrolidones, 
especially N-methyl-, N-octyl, N-decyl, and N-cyclohexyl-pyrrolidone; 
tetrahydrofuran, aliphatic or aromatic or heterocyclic substituted 
alcohols, such as tetrahydrofurfuryl alcohol. 
Surface wetting spreaders (surfactant with dispersant properties) which can 
be used in the invention may be of any type compatible with the plant 
protecting agent, anionic or non-ionic or cationic or amphoteric 
surfactants. They include salts of lignosulphonic acids such as calcium 
lignosulfonate, salts of phenyl sulphonic or naphthalene sulphonic acids, 
condensed naphthalene sulfonic acid; poly condensates of ethylene oxide 
with fatty alcohols or fatty acids or fatty esters or fatty amines, or 
substituted phenols (particularly alkyphenols or arylphenols); salts of 
sulphosuccinic acid esters, such as sodium sulfosuccinate; taurine 
derivatives (particularly alkyltaurates); phosphoric esters of alcohols or 
of polycondensates of ethylene oxide with phenols; esters of polyols and 
of fatty acids or sulphuric acid or sulphonic acids or phosphoric acids; 
glyceryl esters , especially esters with fatty acids such as glyceryl 
stearate; substituted ethylene glycols; and the like. 
Specific surface active agents which are advantageous which may further be 
added to the compositions of the invention are: dialkyl sulfosuccinates; 
alkylbenzene sulfonates salts, such as calcium dodecyl benzene sulfonate; 
ethoxylated tristyryl phenols, and sulfates and phosphates thereof; alkyl 
poylethoxyether phosphates esters, either in acid or in salt form; 
ethoxylated fatty acids or alcohols; ethoxylated alkyl phenols or dialkyl 
phenols; ethoxylated castor oil; ethoxylated propoxylated block 
copolymers; ethoxylated propoxylated alkylphenol block copolymers; 
ethoxylated propoxylated tristyrylphenols; glycerol esters, especially 
esters of fatty acids; glycol esters, especially esters of fatty acids; 
lecithin and lecithin derivatives; sugar esters and other derivatives, as 
sorbitol, and sucrose or glucose esters or derivatives; sucroglycerides. 
Gelling agents which can be used in the invention are generally solid and 
have low solubility in the plant protecting composition and are able to 
form a homogeneous mixture as can be seen visually with the surface active 
agent of the plant protecting composition. Furthermore, the gelling agent 
is preferably also able to form a homogeneous, as can be seen visually, 
ternary mixture with the solvent and the surface active agent. It happens 
sometimes that the gelling agents are mixtures of different compounds 
which might not be gelling agents alone. 
Gelling agents which can be advantageously used are: polyacrylic 
derivatives such as polyacrylic salts, especially the alkali or ammonium 
salts; sodium dioctyl sulfosuccinate, optionally mixed with organic salts, 
such as sodium benzoate; silica; sodium acetate in combination with other 
compounds; urea; alumina; titanium dioxide; sugars; lignosulfonates; salts 
of alkyl arylsulfonates, such as sodium dodecyl benzene sulfonate ; 
combinations of modified clay and propylene carbonate; hydrogenated castor 
oil; ethoxylated vegetable oil; tetramethyl decynediol; mixtures of 
dimethyl hexane diol and hexyne diol; and mixtures thereof. Some gelling 
agents might have both an surface acting action and a gelling action such 
as ethoxylated/propoxylated alkyl phenol block copolymers; ethoxylated 
alkyl phenols and dialkyl phenols; ethoxylated fatty acids; ethoxylated 
fatty alcohols; ethoxylated propoxylated block copolymers; and mixtures 
thereof. 
The gel material which is used in the invention is essentially a material 
which has a phase difference phi between the controlled shear stress and 
the resulting shear strain such that Tg(phi) is less than or equal to 1.5. 
Tg(phi) is the tangent of the phi angle (or phase difference). The 
measurement of phi is made by means of a dynamic rheometer. Dynamic 
rheometers which are appropriate to measure phi are known and available 
commercially. They usually have a flat fixed plate and a rotating cone or 
plate, or a so-called couette measuring system. Other mechanical systems 
are also available. Generally the choice of one system or another is made 
according to the recommendations of the seller of the rheometer, and is 
adapted to the kind of compound, gel or liquid, which is tested. The 
particular choice of a specific type of rheometer is something well known 
by the man skilled in the art of rheology. A rotating plate over another 
plate or a cone rotating over a plate are often more appropriate when a 
gel or a viscous liquid is tested. When two kinds of system for the 
rheometer are possible, similar values of phi are actually measured. The 
cone (or the plate or the couette) is caused to rotate by means of a 
controlled speed motor; the rotation is a sinusoidal one, i.e., the strain 
and the angular displacement change as a sine function with time. Tg(phi) 
is equal to the ratio G"/G', wherein: G' is the storage modulus 
(represents the behavior of a perfect solid); G" is the loss modulus 
(represents the behavior of a perfect liquid). G' and G" are expressed in 
Pascal for a given rotational speed (radian per second). 
G' and G", and thus Tg(phi), may depend on the amplitude of the 
oscillations (percentage of strain) of the rheometer; however, there is 
generally a so-called viscoelastic plateau whereby the values G' and G" of 
a gel do not depend substantially on the said amplitude; this means that 
in the conditions of the test under the viscoelastic plateau the structure 
of the gel is maintained and no destruction of the gel into a liquid 
happens. Of course, the measurement of G' and G" of a gel is made under 
the conditions of this viscoelastic plateau, just because it corresponds 
to the normal gel structure which is precisely what is tested. 
G' and G", and thus Tg(phi), may also depend on the speed of the 
oscillations (time to reach the chosen percentage of strain; expressed as 
radian per second) of the rheometer; however, when the gel is well 
structured, there is no so much variation from one speed to another. In 
order to have a reasonable measurement of the properties of a gel, it is 
generally preferred to operate in conditions whereby the gel is not too 
much stressed, that is to say at speed such as 1 rd/s. Of course, 
measurements at higher speed may also be made. 
As already stated, the plant protecting unit comprise a plant protecting 
composition contained in a water soluble envelope, the said composition 
comprising a plant protecting active ingredient and a solvent and at least 
one gelling agent and at least one surface active and optionally, but 
preferably, a sticker and/or a spreader. 
The amount of active ingredient in the plant protecting composition of the 
invention is generally comprised between 0.1 and 60% of the total plant 
protecting composition contained in the envelope, preferably between 1 and 
40% (in the present specification, unless otherwise specified , the 
percentage are w/w). 
The amount of solvent in the plant protecting composition of the invention 
is generally comprised between 10 and 95% of the total plant protecting 
composition contained in the envelope, preferably between 30 and 90%. 
The amount of surface active agent (wetting spreader) in the plant 
protecting composition of the invention is generally comprised between 0.5 
and 30% of the total plant protecting composition contained in the 
envelope, preferably between 0.8 and 20%. 
The amount of gelling agent in the plant protecting composition of the 
invention is generally comprised between 0.1 and 20% of the total plant 
protecting composition contained in the envelope, preferably between 0.3 
and 10%. 
The amount of sticker in the plant protecting composition of the invention, 
if any, is generally comprised between 0.0% and 20% of the total plant 
protecting composition contained in the envelope, preferably between 0.5% 
and 20%, more preferably between 0.5 and 10%.

The following examples are given to illustrate the inventions and some mode 
of realization. It is not intended to restrict the invention to these 
particular examples. One of ordinary skill in the art could select 
solvents, gelling agents, films and the like. 
EXAMPLE 1 
An insecticidal composition was made by attrition grinding of a mixture 
off: 
1.33% of a 1-haloaryl 3-CN pyrazole whose water solubility is 3 mg/liter at 
20.degree. C. 
85.1% of corn oil which is immiscible with water 
5% of N-Methyl-pyrrolidone 
6% of alphadecyl omegahydroxy hexaethoxylated decylalcohol which is a 
wetting agent 
2.5% of sodium dioctyl sulfosuccinate mixed with sodium benzoate 
0.07% of a tracer dye 
The Brookfield viscosity was 3000 cps; the density was 0.929 g/cm.sup.3. 
This composition was put in a polyvinyl alcohol water soluble envelope 
which was closed by heat sealing. 
10 similar envelopes are dropped onto a rectangular paddy comprising 10 
sub-rectangles of 10 m.sup.2 each. One envelope is dropped on each 
sub-rectangle. The envelope dissolves in less than 3 minutes. The 
composition spreads in 30 minutes covering over the whole paddy and sticks 
to the stem. 
The insecticidal effect, as determined six days after treatment by 
measurement of the percentage of plants damaged by rice water weevil, was 
6.6%.