The present invention relates to insecticidal compositions. More particularly the
present invention relates to a synergistic insecticidal composition comprising
Bifenthrin and Thiamethoxam.
BACKGROUND OF THE INVENTION
To enable the efficient elimination or controlling of unwanted insects in
agricultural and other applications, it is desirable to use effective chemical
insecticides on these unwanted pests. Formulations containing multiple
insecticides are desirable in order to broaden the spectrum of economically
important insect, mite, and other pest species killed or controlled and take
advantage of the individual insecticidal characteristics of each of the active
ingredients.
Compositions containing two or more insecticides have been practiced in the art,
but problems with the physical stability of such mixtures in water have caused
application and efficacy issues. When traditional insecticidal compositions are
combined, the combined components (surfactants, viscosity modifiers, wetting
agents) of both may cause accelerated physical degradation (phase separation) of
the mixture when diluted in low to moderately hard water. This physical
degradation can occur in the mix tanks prior to application on plants or another
locus where control is desired. Often this problem goes unnoticed and a uniform
application of the insecticide mixture is not achieved, yielding inadequate
efficacy.
Typically, in commercial applications, the insecticidal formulation comprises less
than one percent of the tank mixture to keep the cost of the formulation low, while
still yielding spectrum and onset of visual symptomology benefits. The physical
stability of the formulation when diluted with water is a key problem in the art.
An insecticidal composition must satisfy a range of requirements to be viable in
the market. One such requirement of the insecticidal composition is the ability to
be selective in biological action and have low toxicity and a high margin of safety
1011/PAT APPLN/11
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to humans, crops, economic animals, aquatic organisms and birds. Another
requirement is the desire that the composition should be environmental-friendly in
that there should be demonstrably low impacts on the environment. Further, there
should be none or little insect resistance to such compounds or combinations. A
number of pesticidal compositions comprising Bifenthrin or Thiamethoxam are
known in the art.
Bifenthrin is a pyrethroid ester insecticide/acaricide known for controlling a
variety of pests. US patent 4238505 offers a description of Bifenthrin and some of
its uses. Bifenthrin is generally known as 2-methylbiphenyl-3-ylmethyl
(1RS,3RS)-3-[(Z)-2-chloro-3,3,3-trifluoroprop-1-enyl]-2,2-dimethylcyclopropane
carboxylate or
2-methylbiphenyl-3-ylmethyl (1RS)-cis-3-[(Z)-2-chloro-3,3,3-trifluoroprop-1-
enyl]-2,2-dimethylcyclopropanecarboxylate, CAS registry number 82657-04-3
having structure
Bifenthrin is also described in The Pesticide Manual, page 104 (entry 83), Ed.
C.D.S. Tomlin, 15th Edition, 2009. Bifenthrin acts on nervous system of insects,
1011/PAT APPLN/11
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disturbs the function of neurons by interaction with the sodium channel, may
cause paralysis or death and is effective against broad range of foliar pests,
belonging to order Coleoptera, Diptera, Heteroptera, Homoptera, Lepidoptera,
Orthroptera and some species of order Acarina in variety of crops like cereals,
fruits, vegetables, vines etc. Bifenthrin is mainly known for offering control over
lepidopterous insects of the Noctuidae family, especially those popularly known
as caterpillars.
Thiamethoxam (IUPAC: 3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-
oxadiazinan-4-ylidene(nitro)amine and CAS Registry Number 153719-23-4)
belongs to the neonicotinoid insecticide class, more specifically to the class of
neonicotinoid in the nitroguanidine form and was first reported by R. Senn et. al.
in Proceedings of Br. Crop Protection Conference – Pests Dis., 1998,1,27. The
structure, as depicted in the FAO Manual, is as follows:
Thiamethoxam acts as agonist of the nicotinic acetylcholine receptor, affecting the
synapses in the insect nervous system. Thiamethoxam is a contact and systemic
insecticide with contact and stomach action, rapidly taken up into the plant and
transported acropetally in the xylem. It is widely used for control of widespectrum
of insect-pests like aphids, whitefly, Colorado beetles, thrips, hoppers,
bugs, grubs and lepidopteran species etc. in a wide range of
agricultural/horticulture crops.
The standard composition of Bifenthrin available in the art is 10% emulsifiable
concentrate and 8% suspension concentrate and that of Thiamethoxam is 25%
water dispersible granules.
1011/PAT APPLN/11
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As stated earlier, numerous patent documents disclose pesticidal compositions
comprising Bifenthrin or Thiamethoxam. For example, German Patent
DE19956098 discloses a Synergistic plant fungicide composition containing A)
spiroxamine, (B) quinoxyfen and (C) imidacloprid, thiacloprid and/or
thiamethoxam especially effective against cereal diseases.
WO9740692 discloses combinations of any one of several oxadiazine derivatives
with one of a long list of other insecticides. Although the application mentions
that the combinations can be applied to plant propagation material for its
protection, as well as to plant shoots and leaves, no examples are provided to
demonstrate that any one of the combinations listed is actually efficacious. Further
pesticide combinations are described in U.S. Pat. Nos. 4,415,561, 5,385,926,
5,972,941 and 5,952,358.
Prior art patent application EP 1962591 A2 discloses the combinations of
Bifenthrin with other insecticides, for example, a combination of enriched
Cypermethrin and Bifenthrin. Similarly, US 20120122856 A1 discloses a liquid
termiticide composition comprising Bifenthrin and Clothianidin and US 8092816
B2 discloses house hold insecticide combination of Bifenthrin with Imidacloprid.
However, in the existing art, little or no guidance has been found as methods for
predicting which combinations of pesticides will result in unexpectedly superior
efficacy and which combinations will not. These documents also do not disclose
the particular combination of Bifenthrin and Thiamethoxam nor do they disclose
the concentration ranges and the ratios of Bifenthrin and Thiamethoxam which
show synergistic effect.
In a view of afore mentioned there is a need of preparing synergistic insecticidal
composition comprising an effective amount of Bifenthrin (an pyrethroid) and an
effective amount of Thiamethoxam which provides improved efficacies at lower
concentration compared to that observed with the individual components.
Additionally, there is a demand for providing mixtures having synergistic
insecticidal properties, in particular for controlling insects such as chewing and
biting insects, mites, borers, hoppers, and representatives of the order Lepidoptera.
1011/PAT APPLN/11
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SUMMARY OF THE INVENTION
The present invention relates to synergistic insecticidal composition for wide
spectrum control of insect pests, delaying the appearance of the resistant strains of
the insect-pests, minimizing the risk of development of resistance, and achieving
effective and economical control of undesired insect-pests.
In accordance with an embodiment of the invention, there is provided a
synergistic insecticidal composition, comprising: (a) Bifenthrin; and (b)
Thiamethoxam.
The synergistic insecticidal composition comprises Bifenthrin and Thiamethoxam
in a mass ratio in the range from 1:0.40 to 1:0.60. The mass ratio of Bifenthrin to
Thiamethoxam is preferably 1:0.50.
In accordance with another embodiment of the invention, the synergistic
insecticidal composition comprises Bifenthrin in an amount of about 10% and
Thiamethoxam in an amount of 4.0 to 6.0%.
The synergistic insecticidal composition, further comprising excipients, may be
formulated as an emulsion concentrate (EC), a suspo-emulsion (SE), a micro
emulsion (ME), an encapsulated suspension (CS), a water dispersible granule
(WG or WDG) or a suspension concentrate (SC).
The excipients are selected from the group consisting of a solvent, an emulsifier,
an anti-freezing agent, a dispersing cum wetting agent, a defoamer, a biocide, a
thickener and water, and the composition is preferably formulated as a suspoemulsion
(SE).
In accordance with still another embodiment of the invention, the synergistic
insecticidal composition comprises a solvent in an amount of 0 to 10%, an
emulsifier in an amount of 0 to 5%, an anti-freezing agent in an amount of 0 to
8%, a dispersing cum wetting agent in an amount of 2 to 10%, a defoamer in an
amount of 0.01 to 0.50%, a biocide in an amount of 0.01 to 0.50%, and Xanthan
gum as thickener in an amount of 0.10 to 0.50%.
1011/PAT APPLN/11
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In accordance with yet another embodiment of the invention, the synergistic
insecticidal composition is non-phytotoxic and stable.
The invention further relates to the use of the formulations according to the
invention for the control of insects that affect edible and non-edible crops. In
accordance with a further embodiment of the invention, there is provided a
method for controlling insects, comprising contacting crops or their environment
with an agrochemically effective amount of the synergistic insecticidal
composition, wherein the crops are cereals, pulses, vegetables and fruits, and
wherein the insects are from the orders and sub-classes hemiptera, lepidoptera,
coleoptera and arachnida.
In accordance with a still further embodiment of the invention, the synergistic
insecticidal composition of the present invention may be used to control insects
such as aphid, jassid, thrips, white fly, borers, stem borer, leaf folder or mites.
It was surprisingly observed that using the composition comprising Bifenthrin and
Thiamethoxam in the ranges in accordance with the invention leads to much better
control of the different insect pests in comparison to the individual commercial
formulations, reduced volumes of spray in comparison to individual commercial
formulations are required, and this considerably reduces the spray of individual
active ingredients in the combination formulations and lower grams per hectare of
the active ingredients are sprayed than the individual commercial formulations.
Consequently, the residual amount of insecticides in the crops is also much lower,
which reduces the environmental load/residues considerably. Thus, the toxic
effects of the residues of the active ingredients on the biotic and abiotic part of the
ecosystem are minimized.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1. is a flowchart for preparing a synergistic insecticidal composition in the
form of a suspo-emulsion (SE).
1011/PAT APPLN/11
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DETAILED DESCRIPTION OF THE INVENTION
Discussed below are some representative embodiments of the present invention.
The invention in its broader aspects is not limited to the specific details and
representative methods. The illustrative examples are described in this section in
connection with the embodiments and methods provided. The invention according
to its various aspects is particularly pointed out and distinctly claimed in the
appended claims read in view of this specification and appropriate equivalents.
It is to be noted that, as used in the specification and the appended claims, the
singular forms "a", "an" and "the" include plural referents unless the context
clearly dictates otherwise. Thus, for example, reference to a composition
containing “a compound” includes a mixture of two or more compounds. It should
also be noted that the term “or” is generally employed in its sense including
“and/or” unless the content clearly dictates otherwise.
The expression of various quantities in terms of “% w/w” or “%” means the
percentage by weight, relative to the weight of the total solution or composition
unless otherwise specified.
The term "agrochemically effective amount" is that quantity of active agent,
applied in any amount which will provide the required control of pest and
diseases. The particular amount is dependent upon many factors including, for
example, the crop, pest and disease sought to be controlled and environmental
conditions. The selection of the proper quantity of active agent to be applied,
however, is within the expertise of one skilled in the art. The term “active agent”
or “active ingredient” used herein refers to that component of the insecticidal
composition responsible for control of undesired insect-pests.
Compositions comprising a single insecticidal active component suffer from
numerous drawbacks such as development of resistant insect species, requirement
of high amount and concentration of the active ingredient, environmental damage,
seepage of the active component into ground water, phyto-toxicity and harmful
effects on the health of animals and humans.
1011/PAT APPLN/11
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Accordingly, the inventors of the present invention have formulated a synergistic
insecticidal composition, comprising: (a) Bifenthrin; and (b) Thiamethoxam;
wherein the mass ratio of Bifenthrin to Thiamethoxam is in the range from 1:0.40
to 1:0.60, preferably 1:0.50.
The synergistic insecticidal composition of the present invention, further
comprising excipients, may be formulated as an emulsion concentrate (EC), a
suspo-emulsion (SE), a micro emulsion (ME), an encapsulated suspension (CS), a
water dispersible granule (WG or WDG) or a suspension concentrate (SC).
Preferably, the synergistic insecticidal composition is in the form of a suspoemulsion,
and comprises excipients such as a solvent, an emulsifier, an antifreezing
agent, a dispersing cum wetting agent, a defoamer, a biocide, a thickener
and water. The term “suspo-emulsion” used herein refers to a mixture of waterinsoluble
active ingredients dispersed in an aqueous solution, where one (or more)
of the active ingredients is in suspension form and one (or more) of the active
ingredients is in emulsion form. The formulation is intended for dilution into
water prior to spray application. Mixtures of active ingredients are often used to
provide a broader spectrum of pest control. Formulating the active ingredients
together eliminates the need for tank mixing (which can lead to incompatibilities).
Like other aqueous liquid formulations, suspo-emulsions are easy to handle and
measure, dust free, non-flammable and offer good miscibility with water.
Suitable solvents useful in accordance with the invention are C IX,
cyclohexanone, N-methyl pyrollidone (NMP), butanol and combinations thereof,
and present in an amount in the range from 0 to 10%. The term “C IX” refers to a
solvent which mainly comprises of hydrocarbons with nine carbon atoms.
It is desirable to have an emulsifier in the synergistic insecticidal composition. An
emulsifier is a substance that stabilizes an emulsion by increasing its kinetic
stability. One class of emulsifiers are known as "surface active agents",
or surfactants. Non-limiting examples of emulsifiers that can be used in the
present invention include nonionic and anionic surfactants. Each of these
1011/PAT APPLN/11
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surfactants can be used either individually or in combination in an amount in the
range from 0 to 5%.
An anti-freezing agent is generally added to insecticidal compositions, to prevent
the aqueous compositions from freezing. Suitable anti-freezing agents useful
herein, but not limited to, include propylene glycol, di-ethylene glycol and monoethylene
glycol, and combinations thereof. Preferably, the anti-freezing agent is
present in an amount in the range from 0 to 8%.
A dispersing cum wetting agent is another important component of a suspoemulsion
as it facilitates the suspension of a water insoluble substrate in an
aqueous suspension. Non-limiting examples of dispersing cum wetting agent that
can be used in the present invention include non-ionic surfactants and amine salt
of phosphate tristyryl phenol ethylated, acrylic copolymer, ethoxylated
polyarylphenol phosphate ester, each of which can be used individually or in
combination, in an amount in the range from 2 to 10%.
A defoamer, also called as anti-foam, is generally added to an insecticidal
composition as foam formation prevents the efficient filling of a container.
Preferably, the defoamer is dimethyl polysiloxane emulsion and present in an
amount in the range from 0.01 to 0.50%.
The synergistic insecticidal composition comprises a biocide selected from the
group consisting of Proxel GXL, formaldehyde and combinations thereof, and
preferably present in an amount in the range from 0.01-0.50%. Proxel GXL is a
broad spectrum biocide for the preservation of industrial water-based products,
such as the composition of the present invention, against spoilage from bacteria,
yeasts and fungi.
It is necessary to add a thickener to an insecticidal composition to reduce the
tendency of the insecticide composition to disperse when sprayed, and decrease
the likelihood of it being rinsed off of the crops. Preferably, the synergistic
insecticidal composition comprises Xanthan gum as thickener in an amount in the
range from 0.10-0.50%.
1011/PAT APPLN/11
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It has been surprisingly found that the synergistic insecticidal composition of
present invention provides a wide spectrum control of insect pests, delaying the
appearance of the resistant strains of the insect-pests, and achieving effective and
economical control of undesired insect-pests. Accordingly, there is provided a
method for controlling insects, comprising contacting crops or their environment
with an agrochemically effective amount of the synergistic insecticidal
composition, wherein the crops are cereals, pulses, vegetables, and fruits and the
insects are from the orders and sub-classes of hemiptera, lepidoptera, coleoptera
and arachnida. Preferably, the insects controlled using the above method may
comprise aphid, jassid, thrips, white fly, borers, stem borers, leaf folder, mites,
etc.
The present invention is more particularly described in the following examples
that are intended as illustrations only, since numerous modifications and
variations within the scope of the present invention will be apparent to those
skilled in the art. The following examples illustrate the basic methodology and
versatility of the present invention.
Examples 1-3
The unit of each value below is “% w/w” i. e. the percentage by weight, relative to
the weight of the total solution or composition unless otherwise specified. The
compositions contemplated by each of the Examples 1-3 that are tabulated in
Table 1 are formulated as a Suspo-emulsion (SE) formulation.
Table 1: Synergistic insecticidal compositions
Component Function Examples
1 2 3
Bifenthrin **A.I 10.00 10.00 10.00
Thiamethoxam **A.I 4.00 5.00 6.00
1011/PAT APPLN/11
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C-IX Solvent 0.0-5.0 0.0-5.0 0.0-5.0
Butanol Solvent 0.0-5.0 0.0-5.0 0.0-5.0
Blend of Anionic and
Nonionic surfactants
Emulsifier 0.0-5.0 0.0-5.0 0.0-5.0
Diethylene glycol Anti-freeze
agent
0.0-8.0 0.0-8.0 0.0-8.0
Acrylic co-polymenr Dispersing
cum
Wetting Agent
2.0-10.0 2.0-10.0 2.0-10.0
Dimethyl Polysiloxane
emulsion
Deformer 0.01-0.50 0.01-
0.50
0.01-0.50
Formaldehyde Biocide 0.01-0.50 0.01-
0.50
0.01-0.50
Xanthan Gum Thickener 0.10-0.50 0.10-
0.50
0.10-0.50
Demineralized Water Solvent *q.s. *q.s. *q.s.
*q.s. = quantity sufficient
**A.I = Active ingredient
The aforementioned synergistic insecticidal compositions can be formulated as
Suspo-emulsion (SE) by the process described below. The raw materials required
for Examples 1, 2 and 3 are illustrated in table 2 under the column headings 1, 2
and 3 respectively. Entries for Bifenthrin and Thiamethoxam in table 2 differ from
those in table 1 as entries in table 1 are for 100% pure compounds, whereas those
in table 2 are for technical ones, i.e. the ones containing a certain percentage of
impurities.
1011/PAT APPLN/11
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The amounts of active ingredients presented in table 2 may be greater than the
values calculated taking into account the percentage purity of the active
ingredients, to compensate for losses of said ingredients during the manufacturing
process. It was observed that following said procedure on industrial scale the final
yield of A.I. will be similar or same as to standardized values.
Process for preparing a synergistic insecticide composition in the form of
Suspo-emulsion (SE).
The synergistic insecticidal compositions of Examples 1-3 are prepared by the
process depicted in Figure 1. All the raw materials were verified for conformance
to the laid down individual specifications. The required quantities of raw materials
as illustrated in Table 2 below were weighed, and transferred through the autobatching
system. Bifenthrin Technical is first dissolved in suitable solvents, then
emulsifier and water are added, and mixed by high shear mixer to form a
homogeneous emulsion.
The dispersing cum wetting agent is diluted in demineralized (D.M.) water
separately, and solubilized by high shear mixing and then anti freezing
agent, Thiamethoxam technical and deformer, are added and mixed to make
homogeneous mass. The homogenous mass is ground in a Bead Mill until a mean
particle size of 3-5 (D-90) μ is obtained.
After the grinding, the mass is mixed with Bifenthrin homogeneous emulsion and
an aqueous solution of Xanthan gum under stirring. After mixing, the quality of
in-process sample was checked for conformance to the laid out specifications. The
quality approved in-process sample was transferred to the holding tank after
passing through sparkler filter pump for packing as per the requirements.
1011/PAT APPLN/11
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Table 2: Quantities of TGAI* and raw materials charged
Component Function Quantities of
materials charged
(kg)
1 2 3
Bifenthrin (based on 95% w/w
minimum purity)
TGAI* 10.60 10.60 10.60
Thiamethoxam (based on 98% w/w
minimum purity)
TGAI* 4.10 5.12 6.14
C-IX Solvent 3.00 3.00 3.00
Butanol Solvent 2.00 2.00 2.00
Blend of Anionic and Nonionic
surfactants
Emulsifier 3.00 3.00 3.00
Diethylene glycol Antifreeze agent 5.00 5.00 5.00
Acrylic co-polymer Dispersing cum
Wetting Agent
5.00 5.00 5.00
Dimethyl Polysiloxane emulsion Deformer 0.20 0.20 0.20
Formaldehyde Biocide 0.20 0.20 0.20
Xanthan Gum Thickner 0.30 0.30 0.30
Demineralized Water Solvent *q.s. *q.s. *q.s.
*q.s. = quantity sufficient
*TGAI = Technical Grade Active Ingredient
1011/PAT APPLN/11
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Evaluation of the synergistic insecticidal effect of insecticide composition
against insect pests in paddy
Field trials were performed to evaluate the biological efficacy of the synergistic
insecticidal composition of present invention against Leaf folder (Cnaphalocrosis
medinalis) and Stem borer (Scirpophaga incertulas) in paddy and its effect on the
vigour/yield of crops. This evaluation was performed by comparing the claimed
synergistic insecticidal composition of the present invention against the marketed
reference products, i.e., Bifenthrin (WILTHRIN 10% EC) and Thiamethoxam
(WILLOXAM 25% WDG).
Application was made using broadcasting method. Experiments were carried out
in randomized blocks with four replications and each plot measured an area of 100
m2 (10 m x 10 m). The number of freshly folded leaves and dead hearts DH
(drying of the central shoot )/white ear heads WEH (drying up of the entire
panicle of mature plant ) were assessed at 15 days after application (DAA).
Table 3 below summarizes the synergistic effect that exists whenever the action of
an active ingredient combination is greater than the sum of the actions of the
individual components i.e. Bifenthrin and Thiamethoxam against Leaf folder and
Stem borer at different concentrations.
In the field of agriculture, it is often understood that the term "synergy" is as
defined by Colby S. R. in an article entitled "Calculation of the synergistic and
antagonistic responses of herbicide combinations" published in the journal Weeds,
1967, 15, p. 20-22. The action expected for a given combination of two active
components can be calculated as follows:
Where,
E = Expected percentage of insecticidal control for the combination of the two
insecticides at defined doses (for example equal to x and y respectively),
1011/PAT APPLN/11
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X = the percentage of insecticidal control by the compound (I) at a defined dose
(equal to x),
Y = the percentage of insecticidal control by the compound (II) at a defined dose
(equal to y),
When the percentage of insecticidal control observed for the combination is
greater than the expected percentage, there is a synergistic effect.
Table 3: Synergistic effect of separate and combined treatments, for insect
pests, comprising Bifenthrin and Thiamethoxam (SE).
Compound
A.I./ha
% control
at 15
DAA*
Expected
Control
(Et)
Colby’s
Ratio
(Ea+b/Et)
Bifenthrin 50 Ea = 58.61 - -
Thiamethoxam 20 Eb = 41.68 - -
Bifenthrin and Thiamethoxam 50 + 20 Ea+b =
73.17
75.86 0.96
Thiamethoxam 25 Eb = 43.65 - -
Bifenthrin and Thiamethoxam 50 + 25 Ea+b =
89.95
76.67 1.17
Thiamethoxam 30 Eb = 45.00 - -
Bifenthrin and Thiamethoxam 50 + 30 Ea+b =
87.58
77.23 1.13
DAA = Days after application
A.I./ha = Active Ingredient applied as formulation on per hectare basis
1011/PAT APPLN/11
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Ea = % control 15 DAA for Bifenthrin
Eb = % control 15 DAA for Thiamethoxam
Ea+b = % control 15 DAA for a combination of Bifenthrin and Thiamethoxam
Et = Expected % control 15 DAA for Bifenthrin and Thiamethoxam in
combination (Calculated)
It can be seen from the data presented in Table 3 that combinations of Bifenthrin
and Thiamethoxam demonstrate synergistic effect against insect population.
Evaluation of bio-efficacy of synergistic insecticidal composition against
insect pests in paddy
The trials were conducted in Lucknow district of Uttar Pradesh State, India on
paddy following a randomized block treatment with seven compositions and four
replications. For each treatment, 10 plants were randomly tagged per hill, and pre
and post treatment observations were recorded before the spray and 1 DAT (days
after treatment), 3 DAT, 7 DAT and 10 DAT and mean control is calculated.
Based on various doses, weighed quantity of test products were dissolved in 10 L
of water/treatment and sprayed uniformly.
Details of the experiment
Target pests: Leaf folder (Cnaphalocrosis medinalis) and Stem borer
(Scirpophaga incertulas).
Crop: Paddy
Variety: PR-13
Plot Size: 100 m2
Water volume/acre: 200 liters
Spray Equipment: Power operated knapsack sprayers fitted with cone nozzle
Observation: Means of 10 plants/ hill
The treatment details are tabulated in Table 4 below.
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Table 4: Treatment details for evaluation of bio-efficacy of insecticide
compositions against insect pests in Paddy.
Particulars Treatment Dose/Acre
T1 Bifenthrin 10% and Thiamethoxam 4% SE 200 mL
T2 Bifenthrin 10% and Thiamethoxam 5% SE 200 mL
T3 Bifenthrin 10% EC 200 mL
T4 Bifenthrin 10% and Thiamethoxam 6% SE 200 mL
T5 Thiamethoxam 25% WDG 40 g
T6 Bifenthrin 8% EC 250 mL
T7 Control Water spray
The bio-efficacy of different insecticidal compositions on Paddy crop and the
treatment wise yield data of Paddy grain are summarized in the Table 5 and Table
6 below.
Table 5: The bio-efficacy of insecticidal compositions on Paddy crop
Treatment
Stem Borer per cent damage
Leaf Folder damage Per cent Dead mage (%)
Heart (DH)
Per cent White
Ear Head
(WEH)
15
DAA
PR
15
DAA
PR PTC
Mean of 4
observation
PR
T1
2.09
(8.31)
78.14
2.56
(9.21)
76.77 12.00
3.85
(11.32)
78.00
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T2
2.01
(8.15)
78.97
2.39
(8.89)
78.31 11.50
3.76
(11.18)
78.51
T3
5.61
(13.70)
41.32
6.69
(14.99)
39.29 11.48
6.89
(15.22)
60.63
T4
1.92
(7.96)
79.92
2.16
(8.45)
80.40 11.08
3.59
(10.92)
79.49
T5
5.39
(13.42)
43.62
6.13
(14.33)
44.37 11.55
9.83
(18.27)
43.83
T6
5.71
(13.82)
40.27
6.52
(14.79)
40.83 11.57
7.26
(15.63)
58.51
T7
9.56
(18.01)
-
11.02
(19.39)
- 12.01
17.5
(24.73)
-
SEm (±) 0.09 - 0.28 - - 0.18 -
CD at 5% 0.28 - 0.86 - NS 0.56 -
*Value in parenthesis are square root transformed value
PTC: Pre-treatment Count
*SEm ±: Standard Errors of Means; CD 5%: Critical Difference
PR = percentage reduction with respect to control
DAA: Days after Application
NS: Not Significant
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Table 6: Treatment Wise Yield Data
Treatment
Grain Yield
(kg/ha)
Straw Yield
(kg/ha)
T1 4302.0 4655.0
T2 (Bifenthrin 10% and Thiamethoxam
5% SE)
4402.0 4710.0
T3 3885.0 4256.0
T4 4497.0 4821.0
T5 3796.0 4196.0
T6 3656.0 4112.0
T7 2450.0 2892.0
SEm ± 38.32 36.73
CD 5% 118.08 113.18
*SEm ±: Standard Errors of Means; CD 5%: Critical Difference
Treatment with the synergistic insecticidal composition of the present invention
results in a significant reduction of damage caused by Stem borer and Leaf folder.
The use of a combination of Bifenthrin 10% and Thiamethoxam 5% SE, at doses
of 200 mL/ acre, shows satisfactory damage reduction, i.e. 78% reduction in both
Stem borer and Leaf folder at 15 days after the treatment with respect to control.
These results are highly satisfactory and advantageous, considering the difficulty
of controlling these pests and the effect on grain and straw yield.
The phytotoxic effect of different treatment schedules were also observed in ten
randomly selected plants from each plot on 0-10 scale (Table 7) for yellowing,
1011/PAT APPLN/11
21
stunting, necrosis, epinasty, hyponasty etc. Observations were recorded on 1, 3, 7,
and 14 days after application and presented in Table 8.
Table 7: Phytotoxicity visual scoring 0-10
Description of
crop
Rating Remarks
Description of
crop
Rating Remarks
No injury,
normal
0 Immune Severe injury,
no recovery
possible
6 Moderately
tolerant
Slight injury /
discoloration
1 Resistant Sever injury,
stand loss
7 Susceptible
Some stand
crop, stunning /
discoloration
2 Moderately Almost
destroyed, a few
plants surviving
8 Susceptible
Injury more
pronounced but
not persistent
3 Tolerant Very few plants
alive
9 Highly
susceptible
Moderate
injury, recovery
possible
4 Tolerant Complete
destruction
10 Highly
susceptible
Injury more
persistent,
recovery more
doubtful
5 Moderately
tolerant
1011/PAT APPLN/11
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Table 8: Phytotoxic Effect of Different Treatments on Paddy crop
Treatments
Phytotoxicity ratings*
Leaf injury Wilting Vein clearing
R1 R2 R3 R1 R2 R3 R1 R2 R3
T1 0 0 0 0 0 0 0 0 0
T2 (Bifenthrin 10% and
Thiamethoxam 5% SE)
0 0 0 0 0 0 0 0 0
T3 0 0 0 0 0 0 0 0 0
T4 0 0 0 0 0 0 0 0 0
T5 0 0 0 0 0 0 0 0 0
T6 0 0 0 0 0 0 0 0 0
T7 0 0 0 0 0 0 0 0 0
*Observed on 1, 3, 7, and 14 days after spraying and mean values are given
R: Replication
From the foregoing it will be observed that numerous modifications and
variations can be effectuated without departing from the true spirit and scope of
the novel concepts of the present invention. It is to be understood that no
limitations with respect to the specific embodiments illustrated is intended or
should be inferred. It should be understood that all such modifications and
improvements have been deleted herein for the sake of conciseness and readability
but are properly within the scope of the following claims.
1011/PAT APPLN/11
23
We Claim:
1. A synergistic insecticidal composition, comprising Bifenthrin; and
Thiamethoxam.
2. The synergistic insecticidal composition, as claimed in claim 1, wherein
the mass ratio of Bifenthrin to Thiamethoxam is in the range from 1:0.40
to 1:0.60.
3. The synergistic insecticidal composition, as claimed in claim 2, wherein
the mass ratio of Bifenthrin to Thiamethoxam is preferably 1:0.50.
4. The synergistic insecticidal composition, as claimed in claims 1 to 3,
wherein Bifenthrin is present in an amount of 10% and Thiamethoxam is
present in an amount in the range from 4.0 to 6.0%.
5. The synergistic insecticidal composition, as claimed in claims 1 to 4,
further comprises excipients, wherein the composition is formulated as an
emulsion concentrate (EC), a suspo-emulsion (SE), a micro emulsion
(ME), an encapsulated suspension (CS), a water dispersible granule (WG
or WDG) or a suspension concentrate (SC).
6. The synergistic insecticidal composition, as claimed in claim 5, wherein
the excipients are selected from the group consisting of a solvent, an
emulsifier, an anti-freezing agent, a dispersing cum wetting agent, a
defoamer, a biocide, a thickener and water, and wherein the composition is
formulated as a suspo-emulsion (SE).
7. The synergistic insecticidal composition, as claimed in claim 6, wherein
the solvent is selected from the group consisting of C IX, cyclohexanone,
N-methyl pyrollidone, butanol and combinations thereof, and present in an
amount in the range from 0 to 10%.
8. The synergistic insecticidal composition, as claimed in claim 6, wherein
the emulsifier is selected from the group consisting of a nonionic
surfactant, anionic surfactant and combinations thereof, and present in an
amount in the range from 0 to 5%.
1011/PAT APPLN/11
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9. The synergistic insecticidal composition as claimed in claim 6, wherein the
anti-freezing agent is selected from the group consisting of propylene
glycol, di-ethylene glycol, mono-ethylene glycol and combinations
thereof, and present in an amount in the range from 0 to 8%.
10. The synergistic insecticidal composition as claimed in claim 6, wherein the
dispersing cum wetting agent is selected from the group consisting of
mixture of nonionic surfactants and amine salt of phosphate tristyryl
phenol ethylated, acrylic copolymer, ethoxylated polyarylphenol
phosphate ester and combinations thereof, and present in an amount in the
range from 2 to 10%.
11. The synergistic insecticidal composition as claimed in claim 6, wherein the
defoamer is dimethyl polysiloxane emulsion and present in an amount in
the range from 0.01 to 0.50%.
12. The synergistic insecticidal composition as claimed in claim 6, wherein the
biocide is selected from the group consisting of Proxel GXL,
formaldehyde and combinations thereof and present in an amount in the
range from 0.01 to 0.50%.
13. The synergistic insecticidal composition as claimed in claim 6, wherein the
thickener is Xanthan gum and present in an amount in the range from 0.10
to 0.50%.
14. The synergistic insecticidal composition as claimed in any of the claims 1
to 13, wherein the composition is non-