A Broad Spectrum Insecticidal Composition for Agricultural Crops
Field of the Invention
The present invention relates to an insecticidal composition for control of insects/pests in the agricultural crops. More particularly, the present invention pertains to a broad spectrum insecticidal composition with contact and translaminar activity and which is effective against a wide range of biting and chewing type of insects, which composition is highly effective at 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 resulting effective control 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 upon the environment and human beings. The protection of the crops and its produce from pest/insects damage is an inherent requirement which has been 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. Notwithstanding continuous and timely innovations towards enhancing the activity and efficiency of these 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 in long run for all the living organisms including human beings.
Furthermore, although there is a vast array of known insects / pests which are recognized as
potential threat to the agricultural crops and against which targeted insecticides/pesticides
have been developed, unfortunately, the nature, variety, behavioral patterns, mode of
action, growth conditions etc. of these insects / pests varies with changing crops,
geographical parameters, time and several other dynamic parameters. Due to such
unaccounted variation, it has not been possible, despite serious attempts, 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 overuse of insecticides/pesticides, there has always been a natural tendency/adaptability of the insects / pests to develop immunity against the specific concentration of 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, thereby rendering more and more negative impact upon the environment.
Among the presently known insecticidal preparations, various attempts have been made to achieve the maximum effectiveness of the chemicals. However, it has been difficult to enhance the effectiveness of agricultural chemicals merely through adjustments in formulations after an extent. Also, it is practically not feasible to every time invent a new active ingredient to combat the insect resistance and 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 despite the fact that the mixture may not be as effective as desired. Thus, there has been a continuous thrust towards deriving insecticidal compositions which are not only low cost and broad spectrum insecticides, but also invoke minimum or no immunity in the target insects/pests and is environment friendly. Presently, no single insecticidal composition is available for effectively killing a wide range of insects/pests primarily including the biting as well as chewing type. 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. Insofar 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 composition is non-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. biting type, chewing type, piercing type, sucking type etc. 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 translaminar 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 developing 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 or adjuvant 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.
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 Lufenuron and Emamectin benzoate.
It is also an object of the invention to provide a method of preparing the insecticidal composition and its formulations thereof comprising Lufenuron and Emamectin benzoate. Another object of the invention is to provide a broad spectrum insecticidal composition effective with contact and translaminar activity and which is effective against a wide range of biting and chewing type of insects, where the insecticidal composition is highly effective at low doses.
Further object of the present invention is to provide an insecticidal composition that acts at all stages of insects/pests life cycle resulting effective control and has long lasting effect. Yet another object of the invention is to provide a synergistic composition comprising Lufenuron and Emamectin benzoate 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, i.e. Lufenuron and Emamectin benzoate 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.
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
Lufenuron which basically an insect growth regulator and Emamectin benzoate, which is a
neurotoxin that works on synaptic junctions in insects in terms of mode of action.
The first active ingredient of the present composition is Lufenuron belonging to benzoylphenylurea chitin synthesis inhibitors which is a contact and stomach poison acting as chitin synthesis inhibitor resulting in the inhibition of the production of chitin in larvae. After spraying, it enters into the insect's body mostly by ingestion and contact. The affected larvae become unable to moult and do not transform into adults and eventually die. Thus, it interferes with normal growth activity of the immature ones which leads to death of young ones without being developed into adults. Lufenuron has molecular weight of 511.2 with formula as C17H8CI2F8N2O3 and is identified as the following structural formula 1(a):
(Formula Removed)
Lufenuron is selective for larval stage of Lepidoptera and some coleoptera and acts mostly by ingestion and cause inability to moult the larva and also cease feeding. It controls biting and chewing type insects like Lepidoptera and Coleoptera larvae on cotton, maize, vegetables and other field crops.
The second active ingredient is Emamectin benzoate, a neurotoxin that works on synaptic junction in insects in terms of mode of action. Emamectin benzoate acts by stimulating the release of gamma aminobutyric acid (GABA), an inhibitory neurotransmitter, causing paralysis. It is also a contact insecticide with translaminar action. Thus, after spraying on the crop, the active ingredient diffuses into the leaves and accumulates in the leaf-lamina and form the toxic reservoir. This chemical has capacity to kill the hiding insects on the lower surface of leaf due to this trans-laminar activity in addition to the insects which come in direct contact. The trans-laminar activity prevents washing away of the insecticide during rains due to penetration into the plant body after foliar application.
Emamectin benzoate is a mixture of the benzoic acid salt of two structurally complex heterocyclic compounds. It is a mixture containing 90% of (10E, 14E, 16E, 22Z)-(1R, 4S, 5'S, 6S, 6'R, 8R, 12S, 13S, 20R, 21R, 24S)-6'-[(S)-sec-butyl]-21, 24-dihydroxy-5', 11, 13, 22-tetramethyl-2-oxo-3, 7,19-trioxatetracyclo 15.6.1.14,8.020,24]pentacosa -10, 14, 16, 22-tetraene-6-spiro-2'-(5', 6'-dihydro-2'H-pyran]-12-yl 2, 6-dideoxy-3-0-methyl-4-0-(2, 4, 6-trideoxy-3-0-methyl-4-methylamino-a-L-lyxo-hexopyranosyl]-a-L-arabino-hexopyranoside benzoate (B1a) and 10% of (10E, 14E, 16E, 22Z)-(1R, 4S, 5'S, 6S, 6'R, 8R, 12S, 13S, 20R, 21R, 24S)-21, 24-dihydroxy-6'-isopropyl-5', 11, 13, 22-tetramethyl-2-oxo-3, 7,19-trioxatetracyclo [15.6.1.14,8.020,24]pentacosa-10, 14, 16, 22-tetraene-6-spiro-2'-(5', 6'-dihydro-2'H-pyran)-12-yl 2,6-dideoxy-3-O-methyl-4-0-(2, 4,6-trideoxy-3-0-methyl-4-methylamino-α-L-lyxo-hexopyranosyl)-α-L-arabino hexopyranoside benzoate (B1b). The molecular weight of the two isomers are: B1a: 1008.3 and B1b: 994.2. The molecular formula for B1a and B1b are C56H81NO15 and C55H79NO15, respectively and are identified by the following structural formula 2(a), where for B1a: R = CH3CH2- and B1b: R = CH3-.
(Formula Removed)
Individually, Emamectin benzoate acts by stimulating the release of gamma aminobutyric acid (GABA), an inhibitory neurotransmitter, causing paralysis, while Lufenuron inhibits the production of chitin in larvae. Without chitin, a larva is incapable to develop an exoskeleton. Contact and stomach poison is lethal to insects at all the stages of development, as well as causing the inability in the affected larvae to develop into adult ones. Therefore, both the components in the combination assist each other and show synergistic effect. Hence, in the combination both the components are effective at much lower concentration than their recommended doses individually, while the control of pests is fast and better than their alone applications. The combined mode of action of the insecticidal composition also tends to limit the development of immunity in the target population for basically two reasons - by terminating growth of insect population at larval stage itself; 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). Thus, it is possible to achieve a high insecticidal effect against a larger spectrum of insects / pests, whilst using far lower amounts of expensive insecticides and for over a larger period of time. Therefore, the present composition is highly economical and effective. In addition, the composition of the present invention is capable of controlling all stages from egg to adults of major insect pests.
Various experiments and field trails (illustrated in later part of the detailed description) have been conducted to compare the activity of the Lufenuron and Emamectin benzoate, when used solitarily and in combination. The results revealed that when these two insecticides 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 biting and chewing type of insects 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 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 Lufenuron and Emamectin benzoate.
A preferred embodiment describes a composition comprising Lufenuron in an amount ranging from about 1-5% w/w and Emamectin benzoate in an amount ranging from about 1-5% w/w. The composition has been tested against several species of insects and is found to be effective against chewing and biting type of insects.
Alternate embodiments encompass formulations prepared using the composition of the present invention, for example wettable powder (WP), soluble (liquid) concentrate (SL), soluble powder (SP), suspension concentrate (SC), capsule suspensions (CS), water dispersible granules (WG), micro-emulsions (ME), emulsified concentrate (EC) and Soluble granules (SG).
An exemplary formulation based on EC has been described in detail herein, in terms of its preparation (as in Example 1) and use (as in Example 2). The EC comprises Lufenuron and Emamectin benzoate along with one or more suitable adjuvants like solvent, co-Solvent, emulsifier, antioxidant, acidifier, etc.. In the most preferred embodiment related to EC preparation, n-hexanol as solvent; n-methyl pyrolidone as co-solvent; blend of anionic-ethoxylated fatty glycerides & nonionic-ethoxylated sorbitan esters as emulsifier; butylated hydroxytoluene (BHT) as an antioxidant and fumaric acid is used as an acidifier. Other adjuvants and compounds as may be obvious to a skilled artisan are encompassed within the scope of the present invention.
In a preferred embodiment, adjuvants are added in the amount ranging from 90% to 95%; however, the overall amount and that of individual ingredients can be varied as per requirement and depending upon the type of formulation.
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, 500
ml/hectare of EC 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 of preparation of EC comprising 1.5% Emamectin benzoate and 4% Lufenuron. The method comprises adding and mixing solvent and co-solvent, followed by the active ingredient compositions, antioxidant and acidifier. A suitable emulsifier is selected by using a sample of above homogenized mixture and is added to the mixing vessel. After complete homogenization a sample is drawn for quality check like active ingredients, acidity and /or alkalinity, persistence foam, emulsion stability and re-emulsification. Upon meeting the required specifications the homogenized mixture is transferred to storage tank for packaging. The required amount ingredients have been depicted in Table 1 below:
TABLE 1: Ingredients for 1.5% Emamectin benzoate + 4% Lufenuron EC
(Table Removed)
EXAMPLE 2:
Field trial was conducted to evaluate the joint and synergistic effect in term of bio-efficacy and phytotoxicity, of the combination of Emamectin benzoate insecticide and Lufenuron against Diamond back moth, Plutella xylostella Linn., infesting cabbage during March 2011. In particular, the efficacy of EC formulation of the combination of the present invention comprising Emamectin benzoate 1.5% and Lufenuron 4 % was compared with standard checks Emamectin benzoate 1.9% EC and Lufenuron 5.4 % EC applied at recommended doses. The trial design was randomized blocks with four treatments replicated four times. The number of larvae/10 plants was recorded on 1 day before spraying and on 1, 3,7 and 10 days after spraying.
The details of the treatments are given below:
Treatment Dose per hectare
T1-Emamectin benzoate 1.5% + Lufenuron 4 % EC: 500 ml (7.5 gm + 20 gm ai)
T2-Standard Check Emamectin benzoate 1.9% EC 525 ml (10 gm ai)
T3-Standard Check Lufenuron 5.4% EC 600 ml (30 gm ai)
T4-Control Untreated
Table-2: Effect of different treatments of Emamectin benzoate 1.5% + Lufenuron 4 % EC in
control of Diamond back moth (DBM) in cabbage during March - 2011.
(Table Removed)
where,
** = Mean of the No. of live larvae
* = % control of Diamond back moth (DBM) population in cabbage
DAS = Days after spraying
Among different treatments, the composition of the present invention when used @ 500 ml/ha is found the most effective (91.50% - 99.35%) at 1 - 7 DAS in controlling of Diamond back moth infesting cabbage followed by standard check Emamectin benzoate 1.9% EC @ 525 ml/ha (89.44% - 97.46%) at 1 - 3 DAS (Table-2). It was observed that the composition of present invention @ 500 ml/ha showed instant synergistic effect just after spraying and killed the insects pests by physiological (chitin inhibition) effect of lufenuron and neurotoxic effect of Emamectin benzoate simultaneously.
Further, Lufenuron 5.4 % EC @ 600 ml/ha showed the lowest efficacy (ranging from 27.00% to 85.40%) increasingly at every observation among the treatments perhaps because of that lufenuron is a chitin inhibitor, which acts on larval stage of the insect pests and kill them gradually. Lufenuron interferes with the physiology of insect pests during molting by disturbing the chitin synthesis. Thus, Lufenuron 5.4 % EC @ 600 ml/ha showed the lowest mortality initially. While, Emamectin benzoate is a neurotoxin and kills the insect by affecting their nervous system after spraying. Thus, Emamectin benzoate 1.9% EC @ 525 ml/ha showed the efficacy 89.44 - 97.46% up to 3 DAS and the efficacy started to decrease from 7 DAS onwards.
The present composition @ 500 ml/ha showed maximum mortality during the whole period of experiment. Furthermore, the mortality increased up to 3 DAS and remained constant up to 7 DAS. The results clearly indicates that the present composition @ 500 ml/ha was superior and showed maximum efficacy at 3, 7 and even 10 days after spraying among the treatments and showed long lasting effect to control the insect population among the treatments.
EXAMPLE 2;
Field trial was conducted to evaluate the joint and synergistic effect in term of bio-efficacy and phytotoxicity, of Emamectin benzoate in combination Lufenuron against Pod borer, Helicoverpa armigera, infesting pigeon pea during November 2011. More specifically, the
efficacy of EC formulation of the combination comprising Emamectin benzoate 1.5% and Lufenuron 4 % was compared with Emamectin benzoate 1.9% EC and Lufenuron 5.4 % EC applied at recommended doses. The trial design was randomized blocks with four treatments replicated four times. The number of larvae/10 plants was recorded on 1 day before spraying and on 1, 3, 7 and 10 days after spraying.
The details of the treatments are given below:
Treatment Dose per hectare
T1-Emamectin benzoate 1.5% + Lufenuron 4 % EC : 500 ml (7.5 gm + 20 gm ai)
T2- Standard Check Emamectin benzoate 1.9% EC : 580 ml (11 gm ai)
T3- Standard Check Lufenuron 5.4 % EC : 600 ml (30 gm ai)
T4-Control : Untreated
Table-3: Effect of different treatments of Emamectin benzoate 1.5% + Lufenuron 4 % EC in control of Pod borer of Pigeon pea during November - 2011
(Table Removed)
where,
**= Mean of the No. of live larvae
*= % control of Pod borer population in Pigeon pea
DAS = Days after spraying
Result and discussion
Similar results as indicated in Example 2 were observed in this experiment. Among different treatments, the present composition @ 500 ml/ha was found the most effective (92.04%-100.00%) at 1 - 7 DAS of in controlling of Pod borer infesting pigeon pea followed by standard check Emamectin benzoate 1.9% EC (90.48%-98.19%) at 1 - 3 DAS.(Table-3). It was observed that the present composition @ 500 ml/ha showed instant synergistic effect just after spraying and killed the insects pests by physiological (chitin inhibition) effect of lufenuron and neurotoxic effect of Emamectin benzoate simultaneously.
Lufenuron 5.4 % EC @ 600 ml/ha showed the lowest efficacy (ranging from 28.26% to 84.78%) increasingly during the whole period of experiment. Emamectin benzoate 1.9% EC @ 580 ml/ha showed the efficacy 90.48%-98.19% up to 3 DAS and the efficacy started to decrease from 7 DAS onwards.
The present composition @ 500 ml/ha showed maximum mortality during the whole period of experiment. Furthermore, the mortality increased up to 3 DAS and remained constant up to 7 DAS. The results clearly indicate that the present composition @ 500 ml/ha was superior and showed maximum efficacy at 3, 7 and even 10 days after spraying among the treatments and showed long lasting effect to control the insect population among the treatments.
Thus, the overall efficacy indicated in both the experiments that the combinations of Emamectin benzoate 1.5% + Lufenuron 4 % EC @ 500 ml/ha is effective economically, besides being less toxic to the environment and natural enemies in comparison to individual component and shows synergistic effect to control the major insect pests of agricultural crops.
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 Lufenuron and the second active ingredient is Emamectin benzoate.
2. The composition of claim 1, wherein the amount of Lufenuron ranges from about 1-5 %w/w.
3. The composition as claimed in claim 1, wherein the amount of Lufenuron is about 4% w/w.
4. The composition as claimed in claim 1, wherein the amount of Emamectin benzoate ranges from about 1-5% w/w.
5. The composition as claimed in claim 1, wherein the amount of Emamectin benzoate is about 1.5% w/w.
6. The composition as claimed in claim 1, wherein the composition further comprises agriculturally acceptable adjuvants.
7. A method for controlling insects, comprising treating the insects, their habitats or plants with the composition as claimed in claim 1.