GB2358800A

GB2358800A - Kothrine (deltamethrin) containing compositions and their use in controlling insects of the genus Rhynchophorus

Info

Publication number: GB2358800A
Application number: GB0028828A
Authority: GB
Inventors: Moustafa Elewa Moharrem
Original assignee: MOHAMMED AL QUBAISI ENTPR
Current assignee: MOHAMMED AL QUBAISI ENTPR
Priority date: 1999-11-25
Filing date: 2000-11-27
Publication date: 2001-08-08
Anticipated expiration: 2020-11-27
Also published as: GB2358800B; GB9927812D0; GB0028828D0

Abstract

A pesticide formulation comprising Kothrine a can be used to control insects that belong to the genus Rhynchophorous. In particular, this pesticide is the first to be effective against all species of Rhynchophorous and, in comparison to many other insecticides, although it has a high toxicity to the pest it has a significantly lower toxicity to other animals. Kothrine contains the insecticide deltamethrine: <EMI ID=1.1 HE=51 WI=144 LX=423 LY=1439 TI=CF> <PC>```Examples of the Rhynchophorus species include Rhynchophophorus ferrugineus (also commonly referred to as the Red Palm Weevil), Rhynchophorus vulneratus, Rhynchophorus bilineatus, Rhynchophorus palmarum, Rhynchophorus phoenicis, Rhynchophorus schach and Rhynchophorus cruentatus.

Description

"Improved pesticide formulation" The present invention relates to pesticide formulations, and most particularly insecticides for controlling species that belong to the genus Rhynchophorus. Rhynchophorus are one of the most dangerous and destructive pests to a11 types of palm trees, cocoa, sugar cane and a number of other hosts. In the case of palm trees for example, where the insect may be found at all times of the year, the damage is caused by the larval stage. The mature female lays eggs in crevices found in the stem of the tree. The eggs hatch into larvae, which penetrate the stem and feed on its contents, generating tunnels. The damaged tunnels turn necrotic and decay, encouraging the growth of micro-organisms, which in turn results in an unpleasant odour and on occasions a colourless gelatine-like substance can be seen on the outside of the stem holes. The leaves begin to wilt and gradually the tree dies. A number of methods have been used to try and combat the threat of these pests. Many countries including Pakistan, Saudi Arabia, India and the United States have used several insecticides, for example: 1. in United Arab Emirates they have used Marshall, Rogidal, Lindane, DDVP, Rolfan and phostoxin by spraying or injection; and 2. in Saudi Arabia, in recognition of the seriousness of the problem of these pests, the government has allowed the use of substances, which were previously banned, such as Aldrin, Disyston, Gamaxon, Chlordane and BHC.

Similar efforts in other countries in Africa, Asia and America have been found inadequate, the insecticides employed failing to control the pest or penetrate the stem of the palm tree or other host. Frequently, there were also associated problems with toxicity to the plant protection workers.

Other safer countermeasures such as using nematodes that transmit bacteria that are toxic to the pest have been tried, but these failed field-testing. European Patent Number EP '669 321 teaches the use of 4-acyloxy-quinoline derivatives against insects including weevil, mosquitoes, beetles and cockroaches.

However, such is the lack of effective treatment that Commonwealth Entomologist Society, based in London, has recently admitted that the only effective measure is to burn infected hosts. It is an object of the present invention to provide a new insecticide against species of the genus Rhynchophorus at various concentrations and in a number of formulations.

It is a further object to provide an insecticide which is non-corrosive, non volatile and non staining, stable to light and heat, odourless, safe and easy to use.

It is known to use deltamethrine in insecticides. For example, Research Disclosure Number 22830 teaches the use of deltame thrine in combination with methoxychlor for

combatting flea beetles. Deltamethrine is a compound (K-40E;%r,;Ve ;s a feg;,, teed I'GQe ^01-k) found in Kothrine% having the structure:

According to a first aspect of the present invention there is provided a pesticide formulation comprising Kothrine having a deltamethrine compound. Preferably, the pesticide formulation is adapted for combatting the species of the genus Rhynchophorus.

The pesticide may comprise boric acid.

It may additionally or alternatively include borate salts. For example, it might include disodium octaborate tetrahydrate. Preferably, the pesticide formulation is dissolved in or mixed with hot water prior to application.

The concentration of the Kothrine might typically lie in the range of1% to 7.5% by weight.

The pesticide formulation may be provided for use as an emulsifiable concentrate, wettable or dry powder or a flowable.

According to a second aspect of the present invention there is provided a method for controlling species that belong to the genus Rhynchophorous, the method comprising the step of applying a pesticide to a host suited to supporting the species, wherein the pesticide is in accordance with the first aspect of the invention.

The method may comprise mixing a Kothrine formulation with hot water and thereafter spraying the solution onto a said host. The hot water may have a temperature in the range of 30 to 40 degrees Celsius.

Alternatively, the method may comprise the steps of: a) mixing boric acid or a borate with hot water; b) adding and mixing Kothrine; and then c) spraying the solution or mixture on to a said host.

The host might typically be a palm tree. For example, the host might more specifically be a date palm tree, an oil palm tree, an ornamental palm tree or a coconut palm tree. Alternatively, it may be a cocoa plant, papaya tree, sugar cane, pine apple, banana tree, celery plant and so on.

Also according to a further aspect of the invention there is provided a pesticide for controlling the species of the genus Rhynchophorus, wherein the pesticide includes boric acid and or a borate.

The present invention has been developed over a number of years and field studies have been very encouraging. Indeed, this new pesticide is the first to be effective against all species of Rhyn chophorus. Examples of such species include Rhynchophorus ferrugineus, also commonly referred to as the Red Palm Weevil, Rhynchophorus vulneratus, Rhynchophorus bilineatus, Rhynchophorus palmarum, Rhynchophorus phoenicis, Rhynchophorus schach and Rhynchophorus cruentatus.

In order to portray a clearer understanding of the nature and definition of the invention herein, various experiments and example formulations and methods will now be described, but these should not in any way be deemed exhaustive or construed as encompassing all aspects, embodiments or methods falling within the scope of the invention herein intended. Laboratory Experiments 1. Insect rearing Insects were reared using parts of a palm tree stem along with10% sucrose and pieces of apple. The weevils were maintained at 28 C and75% relative humidity on an 8h light . 16h dark cycle. Only male weevils of age 3-4 weeks and larvae of 4-5 weeks were used in lab experiments. Females were used for some gland extract preparations and egg laying. In some experiments weevils were neck-ligated to prevent the release of hormone-like substances from a gland underneath the brain. This hormone-like substance has a hyperglycaemic effect. Ligation was done 12-16 hours prior to the use of the insect.

2. Experiments to show that mites can live symbiotically with weevils Mites were examined under a microscope equipped with a screen. The mite was on the lower surface of the elytra and breath from the tracheal system of the forewing (elytra). Mites lay eggs and developed on this surface. It was noticed that mites feed on particles adhered to the joints of the adult weevil and at its spiracles. This was also noticed in the larvae. So mite feeds from the weevil and at the same time cleans the spiracles and joints of the weevil. Mites have been found on weevils from U.A.E. and Egypt. 3. Physiological and Biochemical Studies The most important source of food for the weevil is carbohydrate, a very good source of energy. Experiments have been performed to determine the levels of carbohydrate in the weevil's haemolymph, central nervous system and fat stores. It is known that the main blood sugar in insects is trehalose and that in the fat stores and the nervous system sugar is stored in the form of glycogen.

Sugar levels in adult weevils: 1. Haemolymph sugar (Trehalose) = 42mM 2. Ventral Nerve Cord Glycogen= 120g/mg wet weight (central nervous system) 3. Fat body Glycogen = 800g/mg wet weight A neurohaemal organ lies under the brain that contains a substance capable of increasing blood sugar levels.

The glands of dissected female weevils were dissolved in Ringer Solution to a specific concentration. 1001 was injected into other insects using an AGZA micrometer controlled syringe through the intersegmental membrane between the sixth and seventh abdominal sternites. 6 hours after injection weevils were bled by piercing the sternum at the base of the coxa of the metathoracic leg. The haemolymph was collected and the level of trehalose was determined. This was done for both ligated and unligated insects.

Weevils o Increase in blood sugar level Unligated 800 Weevils Ligated 720 Weevils Injection of the gland extract resulted in an increase in blood sugar level for both ligated and unligated weevils. This extract is similar to the hyperglycaemic hormone released from the corpus cardiacum and corpus allatum in insects and is known to increase blood sugar level by inducing glycogenolysis of glyocogen in fat stores and the central nervous system.

4. Insecticide Application Experiments 4.1 Topical Application 1001 of insecticide was deposited between the elytra of the insect, on the dorasl surface of the larva, on the cocoon that contains the pupa or directly on eggs.

4.2 Spraying Palm Tree pieces Pieces of Palm Tree containing all the developmental stages of the weevil were sprayed with insecticide.

4.3 Surface Residual Exposure The residual contact effect of the insecticide was determined by allowing the insect to pass through pre- treated filter papers. The following results were obtained: 1. Topical Application 100% mortality for a11 development stages of the mite found under the elytra of the weevil. After 5hrs, adult weevils and larvae showed100% mortality.

2. Symptomatological effect of the Insecticide on the insect Topically treated insects were placed in a glass jar and external symptoms were recorded at intervals. Controls showed no symptoms.

External Symptoms of Time of Appearance after Treated Weevils Treatment in Hours Hyperactivity 1.0 0.01 Tremors 2.0 0.0 Ataxia 3.3 0.4 Falling 4.9 0.4 Prostration 6.0 0.5 Death 12.1 2.6 Skin wilted and became dark * Standard Error of the Mean brown Hyperactivity was noticed after 1hr of treatment with insecticide and after 4-5hrs the insect began to slow down and fall. Prostration was reached after 6hr and death followed after 12hr. The onset of hyperactivity and ataxia indicated a change in energy consumption and accordingly the effects of the insecticide on carbohydrate level in the insect were studied. 3. Effect of Insecticide on Insect Carbohydrate Levels Blood samples, at different intervals, were taken from topically treated, ligated and unligated weevils. The results are detailed in the table below.

Unligated Weevils Ligated Weevils Time Trehalose mM Time Trehalose mM (hr) Control Treated (hr) Control Treated 1 42.73 1. 35.90 0. 1 38.61 3. 42.40 3. 20 87 04 04 2 40.70 43.18 1. 2 35.54 2. 48.97 3. 1.31 69 39 27 4 34.91 0. 20.33 2. 4 31.95 3. 24.55 1. 94 20 90 13 6 36.03 1. 12.98 1. 6 30.26 2. 06.76 3. 05 86 81 26 After 6hrs, the time of prostration, blood sugar levels had decreased by63% in unligated weevils and by77% in ligated ones, indicating that the prostration stage is reached as a result of a sharp decrease in blood sugar level brought on by treatment with the insecticide. In a11 experiments insecticide treatment caused a sharp decrease in blood sugar levels. This hypoglycaemic effect of the insecticide is similar to insulin-shock in mammals. 4. Insecticide effect on insect blood volume The blood volume of topically treated insects was measured at time of prostration, 6hrs. Insects were injected with 1001 of saline containing 26,347 DPM of 14C- inulin. The labelled inulin solution contained 2mM unlabelled inulin as a carrier. Insects were bled by centrifugation 30 minutes after injection. Each sample of blood was collected from two insects. A 1001 sample of haemolymph was placed into a scintillation vial containing 0.4m1 20% KOH to solubilize the protein. 10m1 scintillation fluid was added and the samples were stored in the dark for 24hr to reduce chemiluminescence. Blanks as well as standards were carried through the counting procedure and blood volume was calculated.

Blood Volume (O1) Contr 201.6 of 09.001 Treat 169.5 ed 14.001 Insecticide treatment resulted in 20% decrease in blood volume.

It was also noticed that 6-12hrs after insecticide treatment all developmental stages of the insect (larvae, pupae and adults) had wilted with shrivelled skin and changed colour from white to dark brown, demonstrating that insecticide treatment resulted in a drop on blood volume and dehydration. 5.Ovicidal effect of the Insecticide The egg depositing behaviour of the insect was studied during its rearing. On being laid, eggs were collected with a piece of wood and sprayed with insecticide. The resulting percentage of egg hatching was calculated.

Comments Hatching Treated 0% Colour changed from creamy white to Eggs brown 2 days after treatment. Control 92.3% Colour changed from creamy white to Eggs brown after 3-4 days for the unhatched eggs. The insecticide shows an ovicidal effect.

6. Effect of the Insecticide on all the Developmental Stages of the Red Palm Weevil 1. Topical treatment 100% mortality for a11 developmental stages.

Developmental % Corrected Stage Mortality Larva 100% Pupa 100% Adult 100% All larvae and pupae died approximately 7-8hr after treatment while adults died 11-12hr after treatment.

2. Direct Spraying of Palm Trees 100% mortality for a11 developmental stages. 3. Residual Effect Exposure of the insects to a residual surface the mortality rate was 100% for adults and larvae. None of the pupae died due to the covering of the cocoons, which meant that the pupae were not exposed to the insecticide. However, when the pupa molted into an adult and left the cocoon death followed after 20-21 hr.

Thus laboratory experiments have demonstrated that exposure of the weevil to the insecticide results in 1000 mortality.

Field Experiments The effect of the insecticide against the insects has been studied in a series of field experiments. Experiments were performed at governmental palm farms both in the U.A.E. and elsewhere. In the U.A.E. experiments were performed at: 1. Municipality of Abu Dhabi (Abu Dhabi) 2. Municipality of Al Ain (A1 Ain) 3. Agriculture Department in A1 Ain Government specialists working in the above departments supervised a11 experiments.

The components of the new insecticide were mixed together with hot water and sprayed using portable sprayers. The infected trees were chosen randomly in each experiment and controls were sprayed with hot water. T-test was used for statistical analysis to compare the results for control trees and treated trees. Trees were dissected 7 days after treatment and the percentage mortality was calculated.

In each experiment 3-5 trees were kept undissected to observe the residual effect of the insecticide. Insects that fled during spraying were collected, placed in a glass container with pieces of palm tree and loo sucrose solution and observed. All external symptoms of the infection were recorded before and after treatment.

1. Symptomatological effect of the Insecticide on the insect in field experiments

External Symptoms before External symptoms after Treatment Treatment 1 - Presence of larger holes After 4-6 months secondary roots range from 20-25 cm diameter. had grown in the holes found near the trunk. After 9-10 months disappeared completely 2 - Presence of small round holes After 9-10 months disappeared range from 2.4-5.2cm diameter. completely. 3 - Adults, larvae and cocoons Adults and larvae were escaping could be seen through the holes. during and after spraying and some found dead near tree. 4 - Wilting or yellowing of inner Became bright green 4-6 months leaves. after treatment. 5 - Wilting or yellowing of outer Became bright green 4-6 months leaves. after treatment. 6 - Weak and loose outer leaves. Became strong and secure 4-6 months after treatment. 7 - Characteristic odour emitted Disappeared after 2 days during from the rotting holes. summer and 7-l0 days during winter. 8 - extruding of wet chewed Dried fibres. fibres. 9 - Oozing of white/yellow After 1 day oozing stopped. After gelatinous substance. 2-3 days colour turned dark brown, then dried 10 - Gnawing sound produced by Stopped 1-4hr after treatment. feeding grubs. These symptoms were continuously observed. During and after treatment some adults and larvae fled from the palm tree. These insects were collected and died within 6- 12hr from collection. The numbers were added to the totals for each tree.

2. Repellent effect of the Insecticide Tree No. of Escaping Adults No. of Escaping Larvae Number During After During After Spraying Treatment Spraying Treatment 1 10 3 3 1 2 22 5 2 2 3 12 8 3 1 4 15 1 1 5 23 2 2 5 6 18 - - 7 4 2 2 1 8 16 1 1 9 3 - - 10 9 - - - The above results demonstrate the repellent effect of the insecticide despite the fact that it is odourless.

3. The Insecticidal effect of the Insecticide After 7 days of treatment, treated trees and controls were dissected and the mortality percentage calculated for each developmental stage.

a) In Al Ain Palm Fields Date of % Mortality Experiment Larvae Pupae Adults 09-04-94 100 95.7 100 12-12-94 100 100 100 09-03-95 100 100 97.2 06-04-95 100 100 100 28-05-95 100 100 100 01-01-96 100 100 100 04-03-96 100 95.4 100 05-06-96 100 95.1 100 01-04-97 100 95.7 100 10-0S-97 100 100 100

b) In Abu Dhabi Palm Fields Date of % Mortality Experiment Larvae Pupae Adults 10-11-95 100 100 95.4 08-12-95 100 100 100 06-01-96 100 100 100 The above results further indicate the potent insecticidal effect of this new insecticide.

Treated palm trees that remain undissected showed similar external symptoms to dissected ones and remain healthy in the presence of infected trees. 4. Protective effect of the Insecticide against the Weevil During this experiment 25 young palm trees were used. The trees were sprayed with the insecticide and control trees were sprayed with water. One week after treatment 3 holes were made in each tree, infection with the weevil was achieved by placing 2 adults, 4 larvae and 2 pupae in each tree every 2 weeks for 4 months (the approximate life cycle of the weevil being 4 months). The trees were monitored continuously during this period. The following observations were noted: 1. Adults that escaped from treated trees died within 14hrs whereas those in control trees remained alive.

2. After 4 months all palm trees were dissected.

3. All developmental stages in treated trees were found dead.

4.A11 the cocoons were opened and either the pupae inside or the molted adult were found dead.

5. Control trees decayed within 6-8 weeks from being infected and the insects were found alive.

6. 500 of control trees had a completely hollow stem and fell down.

7. The experiment was repeated three times with similar results being obtained. From these and other laboratory and field tests it may be seen that a pesticide formulation in accordance with the present invention causes a reduction in blood volume and a loss of water resulting in death. This is accompanied by a change in colour of a11 development stages to dark brown. Moreover the formulation induces a prolongation of the opening of the sodium channels of the nervous system. This slows the depolarisation phase of the action potential resulting in repetitive electrical activity along the axons causing paralysis and death.

It has further been found that the pesticide decreases blood sugar in weevils causing a hypoglycaemic coma, similar to insulin-shock in mammals.

The pesticide has been found to be potent against all developmental stages of the weevil, acting by contact or ingestion, and shows an ovicidal effect against weevil eggs. Moreover, the pesticide has also been found to be potent to all stages of development of mites that benefit from the weevil.

It has been further found that the pesticide acts as a repellent against weevils and protects palms from infection or reinfection by weevils for 4 months with no side effects on palm trees or harmful effects on the fruit. The pesticide readily penetrates the stem of palm trees and thus can easily reach its target.

The new pesticide is 2600-5500 times more toxic to the weevil than the rat making it safer to man and other animals than many other insecticides.

From the aforegoing the advantages of the present invention may readily be seen. The invention meets the objectives described heretofor, while providing for the first time, an effective and satisfactory means of controlling all species that belong to the genus Rynchophorous. Further modifications and improvements may be incorporated without departing from the scope of the invention herein intended.

Claims

Claims

(k-o4Ar,,e /'s a V4#1,ffer'od +r4de tnarlr) 1. A pesticide formulation comprising Kothrine) having a deltamethrine compound, wherein deltamethrine has the following structure:
2. A pesticide formulation as in Claim 1 which also comprises boric acid.
3. A pesticide formulation as in Claim 1 or Claim 2 which may also comprise boric salts.
4. A pesticide formulation as in Claim 3 where the boric salt is disodium octaborate tetrahydrate.
5. A pesticide formulation as in any of the preceding Claims which is dissolved in hot water prior to application.
6. A pesticide formulation as in any of the preceding Claims wherein the concentration of the Kothrine lies in the range of to to7.5% by weight.
7. A pesticide formulation as described in any of Claims 1 to 6 which is provided for use as an emusifiable concentrate.
8. A pesticide formulation as described in any of Claims 1 to 6 which is provided for use as a wetable powder.
9. A pesticide formulation as in any of Claims 1 to 6 which is provided for use as a dry powder.
10. A pesticide formulation as in any of Claims 1 to 6 which is provided for use as a flowable substance.
11. A method for controlling species that belong to the genus Rhynchophorous, the method comprising the step of applying a pesticide to a host suited to supporting the species, wherein the pesticide is of a formulation comprising Kothrine having a deltamethrine compound.
12. A method for controlling species that belong to the genus Rhynchophorous as in Claim 11, wherein the pesticide may also comprise boric acid.
13. A method for controlling species that belong to the genus Rhynchophorous as in Claims 11 or 12, wherein the pesticide may also include boric salts.
14. A method for controlling species that belong to the genus Rhynchophorous as in any of Claims 11 to 13, wherein the boric salt is disodium octaborate tetrahydrate.
15. A method for controlling species that belong to the genus Rhynchophorous as in any of the Claims 11 to 14, wherein the pesticide formulation is dissolved in hot water prior to application.
16. A method for controlling species that belong to the genus Rhynchophorous as in any of the Claims 11 to 15, wherein the concentration of the Kothrine in the pesticide may typically lie in the range of 1% to 7.5% by weight.
17. A method for controlling species that belong to the genus Rhynchophorous as in any of the Claims 11 to 16, wherein the pesticide formulation is provided for use as emulsifiable concentrate, wetable or dry powder or a swellable substance.
18. A method for controlling species that belong to the genus Rhynchophorous as in any of the Claims 11 to 17, wherein the Kothrine formulation is mixed with hot water which has a temperature in the range of 30 C to 40 C and then applied to a host suitable for supporting the species.
19. A method for controlling species that belong to the genus Rhynchophorous as in Claims 12 to 17, wherein the method comprises mixing boric acid or a borate with hot water, adding and mixing Kothrine and spraying with solution of mixture onto a said host.
20. A method for controlling species that belong to the genus Rhynchophorous as in any of Claims 11 to 19, wherein the host that the pesticide is applied to is a palm tree.
21. A method for controlling species that belong to the genus Rhynchophorous as in Claim 20, wherein the host is a date palm tree, and oil palm tree, an ornamental palm tree or a coconut palm tree.
22. A method for controlling species that belong to the genus Rhynchophorous as in Claims 11 to 19, wherein the host that the pesticide is applied to is a cocoa plant, papaya tree, sugar cane, pine apple, banana tree or celery plant.
23. A pesticide for controlling the species of the genus Rhynchophorous, wherein the pesticide includes boric acid.
24. A pesticide for controlling the species of the genus Rhyn chophorous as in Claims 23, wherein the pesticide also includes a borate.