Broad spectrum Insecticidal Composition for Agricultural Crops
Field of the Invention
The present invention relates to an insecticidal composition for control of insects/pests as
well as mites in agricultural crops. More particularly, the present invention pertains to a
broad spectrum insecticidal composition effective against piercing and sucking type of
insects and mites; highly effective in low doses; and is also environment-friendly.
Furthermore, the insecticidal composition provided in accordance with the present
invention acts at all stages of insects/pests life cycle and has long lasting effect.
Background of the Invention
In an agriculture based economy, with inadequate resources, it is essential to resort to most
economical and promising agricultural practices. It demands not only consistent efforts
towards enhancing the crop yield but also efforts towards achieving fool proof protection
and stability of crops against the attack of insects/pests and/or mites etc. with minimal or
no side effects on the environment. The protection of the crops and its produce from insect
pests damage is an inherent requirement which is being addressed with the help of a vast
range of insecticides and pesticides for over several decades now. Accordingly, in the
presently existing agricultural practices, the use of organic chemicals and
insecticides/pesticides has become almost inevitable as a curative or as precautionary
measure. Not withstanding continuous and timely innovations towards enhancing the
activity and efficiency of the insecticides, there are enormous losses every year due to the
insect / pest attack on the agricultural crops. Also, consistent use of insecticides/pesticides,
inadvertently results in accumulation of these chemicals in the environment, which is
harmful.
Furthermore, although there is a vast array of known insects / pests which are considered
potential threat to the agricultural crops and against which targeted insecticides/pesticides
could be developed, unfortunately, the nature, variety, behavioral patterns, mode of action
etc. of these insects / pests varies with changing crops, geographical parameters, time and
several other factors. Due to such unaccounted variation, therefore, despite serious
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attempts it has not been able to reach to a universal composition effective against all kind of
insects and/or pests in all agricultural crops and in all conditions. Above all, due to over use
of insecticides/pesticides, there is always a natural tendency/adaptability of the insects /
pests to develop immunity against the particular insecticide/pesticide in use, which results
in use of further increased amounts of insecticide/pesticide. This vicious circle results in use
of continuously increasing amounts of the insecticide/pesticide and thereby increasing
negative impact on the environment.
Among the presently known insecticidal preparations, various attempts have been made to
ach ieve the maximum effectiveness of the chemicals. However, it has been difficult to
enhance the effectiveness of agricultural chemicals merely through adjustments in
formulations. Also, it is practically not feasible to every time invent a new active ingredient
for enhancing the activity and efficiency of the insecticidal composition. Selective
combination has been a means for achieving the desired effects. Any attempt to mix or use
two or more of existing insecticides in order to serve in most diversified conditions,
however, tends to compromise with the cost factor and the environment factor and further
there might be compatibility issues. Thus, there has been a continuous thrust towards
deriving insecticidal compositions which are low cost, broad spectrum, invoke minimum or
no immunity as well as environment friendly. Presently, no single insecticidal composition is
available for effectively killing piercing and sucking type of insects as well as mites. Although
many different compounds have been proposed for use in their eradication, none has been
found competent enough for various reasons. One major problem with the use of these
diversified insecticidal compositions is their high cost per unit dose.
More specifically, while using an insecticide, it must be taken care that the insecticide has
adequate efficacy for the particular target insects or class of insects such that the effective
lethal dosage of the insecticide is practically effective i.e., the effective ingredient of the
overall insecticidal composition are sufficiently high enough to cause the desired insecticidal
effect while simultaneously being at an adequately low level to ensure economical
justification and that no adverse side effects are created thereby. In so far as side effects are
concerned, since the insecticidal composition are generally sprayed or otherwise admitted
to the atmosphere, it is imperatively necessary that the effective constituent of the
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composition is not be toxic beyond the targeted population. Therefore, it is always desired
to have insecticidal composition which is sufficiently effective at minimal doses.
Secondly, most of the active ingredients used for exterminating the harmful insects are
stable in environment, for example in the soil, and remain in the ecosystem, where their
presence has become a problem. It is apparently due to the fact that there are limits to the
amount of petrochemical-based materials that can be safely absorbed into the
environment. There have been some environment friendly and easily degradable .
compositions available presently, but they suffer from their ineffectiveness against a wide
range of insects / pests.
Thirdly, individual insecticidal composition acts in a specific manner for restricting the
growth of a particular type of insects i.e. piercing and sucking type of insects including mites
in agricultural crops as well as plantation & horticultural crops.
It is desired to have insecticidal composition which is active against most or all type of
potential insects i.e. a composition with contact / systemic as well as trans-laminar activity
against the insects. This is also required to prevent the washing-out of sprayed insecticides
due to rain or during irrigation.
Finally and more importantly, it is also known that consistent and excessive use of particular
insecticide results in insects having developed a resistive mechanism to the said particular
insecticide. There has been effort in the past to overcome the problem of resistance such as
minimal use of the insecticide, specific pattern of use of the insecticide and compositions
with addition of particular compounds which acts as a synergist with the insecticide to
overcome to some degree the resistive mechanism. Although such systems are effective to
reduce the resistance, none of them are effective in eliminating the possibility of
development of resistance in the insecticidal population. Thus, it is required to have an
insecticidal composition which is not only instantly effective on the population as a curative
measure, but also has such long-lasting preventive effects that relatively minimum doses are
sufficient. Also, the insecticide should be capable of being used time and again (after the
used amount is dosed out), with minimal or no immunity being developed by the target
population.
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Summary of the Invention
It is an object of the invention to provide a combination of two different active ingredients
which are well known insecticides exhibiting different mode of action; thereby providing a
highly effective and efficacious solution for controlling major insects and pests in various
agricultural crops, wherein the two active ingredients are hexythiazox and a neonicotinoid
insecticides include imidacloprid, thiamethoxam, acetamiprid, thiacloprid, etc.
Another object of the invention is to provide a broad spectrum, insecticide effective against
both piercing and sucking type as well as mites and other type of insects for all the
agricultural crops including plantation and horticultural crops. The invention encompasses a
broad spectrum neurotoxic insecticidal composition with contact, systemic and translaminar
activity.
Yet another object of the invention is to provide a synergistic composition comprising
hexythiazox and a neonicotinoid insecticide, preferably thiamethoxam in synergistically
effective amount, wherein each ingredient significantly enhances and abets the activity of
the other ingredient. This way, the combination of both the active ingredients exhibits a
synergistic effect resulting in a faster and higher mortality of the insect pests. The enhanced
mortality ensures reduction in crop damage by insect pests, thereby resulting in a significant
increase in the overall yield of the crop. Also, the combination of both has made it possible
to achieve a higher insecticidal effect for a larger spectrum of insects/pests.
Another object of the invention is to provide an insecticidal composition that is effective
even when used in far lower amounts as compared to other insecticides that are usually
very expensive; thereby being highly cost effective. Further, since the dose of individual
active ingredient in this composition is far less than the doses required when used alone,
the residue in the soil as well in crop is also lower than their individual residues when used
alone. This eliminates any possible side/adverse effects. Consequently, this combination is
environmentally safer than its parental compounds. Individually, in such infinitesimally low
concentrations, both the components of the combination are very safe to the environment
as well as to any non-target organisms including human beings. Therefore, the present
composition turns out to be highly economical, effective against a large number of insects
and is also environmental friendly.
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It is also an object of the invention to provide a method of preparing the insecticidal
composition and its formulations thereof comprising Hexythiazox and Thiamethoxam.
Further object of the invention is to provide a method of controlling insects wherein the
insects, their habitats and/or plants are treated with the composition of the present
invention.
Description of the Invention
Accordingly, a broad spectrum insecticidal composition is provided in accordance with the
present invention which is capable of controlling major insects and pests in various plants
while it also overcomes some or all of the problems associated with the prior art as
identified above and others.
The composition in accordance with the present invention is a unique combination of
Hexythiazox which basically acts as an acaricide and a compound selected from
Neonicotinoid group of insecticides which are systemic, contact and stomach poisoning
insecticides, where examples of Neonicotinoid insecticides include imidacloprid,
thiamethoxam, acetamiprid, thiacloprid, etc.
The first active ingredient of the composition is Hexythiazox which is primarily an acaricide.
Hexythiazox has molecular weight of 352.88, empirical formula as C17H21CIN2O2S and is
identified as the following structural formula 1(a):
Hexythiazox exhibits contact and stomach action and does not translocate in the plants. It is
an acaricide which has ovicidal, larvicidal and nymphicidal activities and is applied at any
stage of plant growth from budding to fruiting. It interferes with normal growth activity of
the immature ones which leads to death of young ones without developed into adults.
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Hexythiazox kills the eggs before the mites hatch and also immature mites. Adult mites are
not killed, although adults exposed to residues may lay eggs that are not viable. Being a
growth regulator, the chance of development of resistance/immunity in the target mites
against this are minimally or nil.
The second active ingredient is a compound selected from the Neonicotinoid group of
insecticides such as but not limited to imidacloprid, thiamethoxam, acetamiprid, thiacloprid,
etc. These insecticides act as agonists of the acetylcholine receptor. That is, they mimic the
action of the neurotransmitter, acetylcholine (ACh). A preferred insecticide for the present
invention being thiamethoxam of molecular weight 291.71 and empirical formula
C8H10CIN5O3S. It is identified as the following structural formula 2(a). Thiamethoxam is a
systemic and stomach poisoning insecticide that is absorbed quickly by plants and
transported to all parts of the plant, where it acts as a deterrent to insect feeding. It
basically blocks the normal conduction of nerve impulse between nerve cells, making the
insects paralyzed.
The neonicotinoid insecticides, specifically those mentioned above and hereinafter, are well
known in the art, including their structures, properties and other characteristic details.
Besides, being economical and environmentally safe, the combination also targets towards
limiting the development of immunity in the target population for basically two reasons - by
rendering the adults sterile or resulting in infertile eggs; and due to minimal use of
composition (since the excessive use of insecticide is one of the prime reasons of developing
the immunity by the insects).
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Further, the composition of the present invention is capable of controlling all stages from
egg to adults of major insect pests as well as mite pests.
Various experiments and field trails (illustrated in later part of the detailed description) have
been conducted to compare the activity of the hexythiazox and a neonicotenoid insecticide,
specifically thiamethoxam, when used solitarily and in combination, the results revealed
that when hexythiazox and a neonicotenoid insecticide are used together in suitable
amounts, the resulting combination exhibits a higher insecticidal activity, at a much lower
concentration than when either of them is used alone; thereby confirming an excellent
synergistic effect.
The excellent insecticidal activity of the present composition can be seen from the examples
which follow. While the individual active ingredient exhibit weaknesses with regard to the
insecticidal activity, the combination of the two demonstrates enhanced activity which
exceeds the simple summation of individual activity. The combination of the two different
insecticides also provides that a single composition is capable of acting against different
insect types controlled by individual components, thus widening the spectrum of the
composition.
The composition of the present invention is suitable for controlling insect pests encountered
in agriculture. It is effective against both normally sensitive and resistant species of insects;
and is also effective in controlling all or individual stages of development of the insects. The
composition is highly effective against all piercing and sucking type of insects including mites
in agricultural crops as well as plantation & horticultural crops.
The composition in accordance with the present invention is suitable for foliar treatment of
plants and plant parts; wherein the term 'plant' in the present context, may encompass all
plants and plant populations, such as desired and undesired wild plants or crop plants
(including naturally occurring crop plants, plantation and horticulture crop plants}. Crop
plants may further be plants which can be obtained by conventional breeding and
optimization methods or by biotechnological and genetic engineering methods or by
combinations of these methods, including the transgenic plants. Plant parts are understood
as meaning all above-ground and subterranean parts and organs of the plants, such as
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shoot, leaf, flower and root, examples which may be mentioned being leaves, needles,
stalks, stems, flowers, fruiting bodies, fruits and seeds, and also roots, tubers and rhizomes.
The plant parts also include harvested material and vegetative and generative propagation
material, for example cuttings, tubers, rhizomes, slips and seeds.
The invention is further illustrated by the following embodiments which describe the
preparation, utility and effectiveness of the composition encompassed by the invention. The
embodiments are presented merely for the purpose of illustration and should not be
considered as limiting the invention in any way.
In accordance with the above, an embodiment of the present invention broadly covers an
insecticidal composition comprising hexythiazox and a neonicotenoid insecticide including
but not limited to imidacloprid, thiamethoxam, acetamiprid, thiaclonrid, etc.
A preferred embodiment describes a composition comprising hexythiazox in an amount
ranging from about 3-5% w/w and thiamethoxam in an amount ranging from about 3-5%
w/w. The composition has been tested against several species of insects and is found to be
effective against piercing and sucking type of insects including mites. The composition is
capable of exhibiting insecticidal activity at much lesser amount as compared to the amount
of Hexythiazox and Thiamethoxam, when used alone.
Alternate embodiments encompass formulations prepared using the composition of the
present invention, for example wettable powder (WP), soluble (liquid) concentrate (Si),
soluble powder (SP), suspension concentrate (SC), capsule suspensions (CS), water
dispersible granules (WG), micro-emulsions (ME), emulsified concentrate (EC). While the
nature of a few neonicotenoid insecticides is not compatible for EC preparation, appropriate
experimentation overcomes the said limitation.
An exemplary formulation based on SC has been described in detail herein, in terms of its
preparation (as in Example 1) and use (as in Example 2). The SC comprises hexythiazox and
thiamethoxam along with one or more suitable adjuvants like anti-freeze agent, dispersing
agent, wetting agent, deformer, biocide/s, thickening agents, etc. Preferred compounds
include polypropylene glycol as anti-freeze agent, modified alkyl phenol phosphate as
dispersing agent and amine salts of Polyaryl phenyl ether phosphate as the wetting agent;
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however, other compounds and chemicals as may be obvious to the person skilled in the art
may be used for practicing suspension concentrate and other formulations encompassed by
the present invention. For example, WG formulation comprising 4% Hexythiazox and 4%
Thiamethoxam can be prepared by using, inter alia, disposing agent, wetting agent,
plasticizer, carrier, binder corn starch, etc. In preferred embodiment, Sodium Lignosulphate
is used as disposing agent, Sodium Lauryl Sulphate as wetting agent, butylated polyvinyl
pyrrolidine as plasticizer, diatomaceous earth as carrier. Other compounds may be used as
adjuvants to pre'pare WG formulation.
In a preferred embodiment, adjuvants are added in the amount ranging from 90% to 92%;
however, the overall amount and that of individual ingredients can be varied as per
requirement and depending upon the type of formulation.
The desired particle size for the present composition varies from formulation to
formulation. For example, SC works best with particle size in the range of 3 to 5 micron and
particles of less than 5 micron size are preferred for SC.
An embodiment of the present invention also describes the method of controlling insects by
using the insecticidal composition of the present invention. The method comprises treating
the insects, their habitats or the plants with said composition. In a preferred instance, about
400 ml to 1000 ml/hectare of SC form of the composition was used for treatment of
infected plants. The amount can be varied depending upon the species, abundance of the
insects on the plants, etc.
To further assist in the understanding of the present invention and not by way of limitation,
the following examples are presented:
EXAMPLE 1:
An example described the most preferred method for preparation of SC comprising the 4%
Hexythiazox and 4% Thiamethoxam. The method comprises diluting 5% of modified alkyl
phenol phosphate and 2% of an amine salt of Polyaryl phenyl ether phosphate in D.M.
Water and solubilizing by high shear mixing. This is followed by adding 8 % of propylene
glycol, 4% of Hexythiazox ai (active ingredient), 0.20% of deformer and homogeneously
mixing the above and adding 4% of Thiamethoxam ai. The above mixture is mixed to make
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homogeneous mass which is then grounded in Sand Mill until a mean particle size of 3-5
microns is obtained. Pursuant to grinding, 2% water solution of xanthum gum is added
under low stirring conditions and is homogeneously mixed. A sample is drawn and tested
for quality parameters like active ingredients, physical stability, acidity, persistence foam,
flowability or suspensibility etc.; is packed if found meeting the specifications.
TABLE 1: Ingredients for 4% Hexythiazox + 4% Thiamethoxam SC
EXAMPLE 2:
A field experiment was carried out to evaluate the efficacy of this SCthis insecticidal and
acaricidal combination in different doses. The Suspension Concentrate (SC) comprising 4%
Hexythiazox and 4% of Thiamethoxam was tested on tea crop (12 years old bushes) infected
with Red Spider Mite (RSM) and Mosquito Bug (MB) in April-May, 2011. The experiment was
carried out with 7 treatments; each treatment replicated thrice using randomized block
design, while following all agronomic package of practices. The soil of experimental site was
sandy loam and water used for dilution was the normal soft water of neutral pH. The
prescribed quantities of different insecticides (test samples) were dissolved in required
quantity of water and used for evenly spraying (using knapsack sprayer pump) over the
infected plants, at the rate of 500 l i t / ha. The percentage reduction / increase of the pest
was observed at 0, 1st, 5th, 10th and 15th day after spraying (DAS). In this test, the
composition exhibited a synergistically enhanced activity compared to the active
compounds applied on their own as shown in Table 2(a) and 2(b). Similarly, Table-3 depicts
effect of different treatment of Hexythiazox 4% + Thiamethoxam 4 % SC (CPL4040) on yield
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during the control of Red Spider Mite (RSM) and Mosquito bug (MB) of Tea during April May
-2011
Table-2{a): Effect of different treatment of Hexythiazox 4% + Thiamethoxam 4 % SC in
control of Red spider mite (RSM) of Tea during April May- 2011 (mean of three replications)
**= Mean of the No of live nymph/bush
*= percent reduction / increase (+) RSM population in tea
Table-2(b): Effect of different treatment of Hexythiazox 4% + Thiamethoxam 4 % SC in
control of Mosquito Bug of Tea during April May - 2011 (mean of three replications)
**= Mean of the No of live nymph/bush
*= percent reduction / increase (+) MB population in tea
Table-3: Effect of different treatment of Hexythiazox 4% + Thiamethoxam 4 % SC (CPL4040)
on yield during the control of Red Spider Mite (RSM) and Mosquito bug (MB) of Tea during
April May-2011
In accordance with the above experiments, the percent reduction/increase in Red spider
mite (RSM)/ Mosquito bug (MB) population is worked out based on the number of nymph
and adult stages of the Red spider mite / Mosquito bug in 20 bushes/plot selected at
random. The observations on pest incidence were taken one day before and on 1s t 5th, 10 th
&15 days after spraying. Further, while the observations for RSM (nymph & adults)
populations were taken from three leaves per twig and three twigs per bush randomly, the
observations for MB (nymph & adults) populations were taken per bush randomly.
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As shown in Table 1 and 2, maximum reduction (89.32% and 91.07%) of RSM and MB
(nymph & adult) populations respectively were observed on 10th day after spraying with the
higher dose i.e., 1000 ml /ha followed by 600 ml /ha and 500 ml /ha.
From the point of view of cost, the test combination Hexythiazox 4% + Thiamethoxam 4 %
SC (CPL4040) @ 500 ml/ha shows significant efficacy (87.75% and 87.71% for RSM and MB
populations, respectively) over the standard checks and significantly at par with the higher
doses on 1st, 5th, 10 th & 15th days after spraying.
According to the table-3, percent increase in the yield over control observed with
Hexythiazox 4% + Thiamethoxam 4 % SC (CPL4040) @ 500 ml /ha was 51.14%, which was
significantly at par with the higher doses.
Similarly, other field trails were performed with other crops and insects where consistent
results were observed indicating enhanced efficacy of the combination and increased
activity of individual components.
Although the present invention has been described in considerable detail with reference to
the above embodiments and examples thereof, other embodiments and equivalents are
possible. Also, even though numerous characteristics and advantages of the present
invention have been set forth in the forgoing description, together with functional and
procedural details, the disclosure is illustrative only, and changes may be made in detail,
especially in terms of the examples of ingredients of the composition within the principles of
the invention, to the full extent indicated by the broad general meaning of the terms in
which appended claims are expressed. Thus various modifications are possible of the
presently disclosed composition without deviating from the intended scope and spirit of the
present invention. More particularly, the composition, as depicted in the present invention,
is seemingly a simplified and generalized one and there are several trivial variations possible
that may be included in the scope of the present invention.

We claim,
1. A composition comprising synergistically effective amount of two active ingredients,
wherein the first active ingredient is Hexythiazox and the second active ingredient is
a Neonicotinoid insecticide.
2. The composition of claim 1, wherein the amount of Hexythiazox ranges from about
3-5 % w/w.
3. The composition as claimed in claim 1, wherein the amount of Hexythiazox is about
4%-w/w.
4. The composition as claimed in claim 1, wherein the second active ingredient is
Neonicotinoid insecticide such as imidacloprid, thiamethoxam, acetamiprid,
thiacloprid.
5. The composition as claimed in claim 1, wherein the neonicotinoid insecticide is
thiamethoxam.
6. The composition as claimed in claim 1, wherein the amount of thiamethoxam ranges
from about 3-5 % w/w.
7. The composition as claimed in claim 1, wherein the amount of thiamethoxam is
about 4 % w/w.
8. The composition as claimed in claim 1, wherein the composition further comprises
agriculturally acceptable adjuvants.
9. A method for controlling insects, comprising treating the insects, their habitats or
plants with the composition as claimed in claim 1.