GB2074867A

GB2074867A - Improvements in or Relating to Insecticides

Info

Publication number: GB2074867A
Application number: GB8014034A
Authority: GB
Original assignee: Sandoz AG
Current assignee: Sandoz AG
Priority date: 1980-04-29
Filing date: 1980-04-29
Publication date: 1981-11-11

Abstract

A composition comprising quinalphos and a pyrethroid, as well as a method of combatting insects particularly in a cotton locus, using quinalphos and a pyrethroid. Quinalphos is quinoxaline-2-yl-diethyl phosphorothionate and pyrethroids are synthetic derivatives of the natural insecticidal constituents of the pyrethrum powder extract from the flower heads of Chrysanthemum Cinerariaefolium.

Description

SPECIFICATION Improvements in or Relating to Insecticides The present invention relates to an insecticidal composition.

Thus, there is provided an insecticidal composition comprising a) the compound of formula I,

hereinafter referred to by the common name "quinalphos", and b) a pyrethroid.

Pyrethroids are synthetic derivatives of the natural insecticidal constituents of the pyrethrum powder extract from the flower heads of Chrysanthemum Cinerariaefolium, known as pyrethrins.

Preferred pyrethroids for use in this invention are the 3-phenoxybenzyl esters and the a-cyano3-phenoxybenzyl esters of 3-(2 2-dichlorovinyl)- 2,2-dimethylcyclopropane carboxylic acid, 3-(2,2dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid and 4-chlorophenyl-3-methyl butyric acid.

Particularly preferred pyrethroids are permethrin [3-phenoxybenzyl 3-(2,2dichlorovinyl)-2,2-dimethylcyclopropane carboxylate; a mixture of all 4 isomers present, cypermethrin [a-cyano-3-phenoxybenzyl 3-(2,2dichlorovinyl)-2,2dimethyl cyclopropanecarboxylate; a mixture of all 8 isomers present], fenvalerate (a-cyano-3- phenoxybenzyl 4-chlorophenyl-3-methyl-butyricic acid ester, a mixture of all 4 isomers present) and decamethrin [1 isomer of a-cyano-3phenoxybenzyl 3-(2,2-dibromovinyl)-2,2dimethylcyclopropane carboxylate].

It has been found that the composition of the invention is particularly effective in combating insect pests in a locus, particularly in cotton, Especially good results are obtained against lepidoptera larvae such as Spodoptera littoralis, Heliothis spp, Pectiniphora gossypiella, insects of the order of Homoptera and against Aphids.

The weight ratio of constituent a) : constituent b) as well as the amount/ha of plant locus to be applied to attain the desired effect will vary on standard variables such as the constituent b) employed, mode of application, ambient conditions and degree of infestation.

However, in general, satisfactory results are usually obtained when the weight ratio of constituent a) : constituent b) n the composition lies in the range of 10:1 to 250:1. In case fenvalerate, permethrin or cypermethrin is employed as pyrethroid, the weight ratio of constituent a) : constituent b) is e.g. preferably in the range of 10:1 to 50:1, in case decamethrin is the pyrethroid employed, the preferred weight ratio of constituent a):constituent b) is e.g. in the range of 50:1 to 250:1.

Thus, the invention also provides a method of combating insects particularly lepidoptera larvae such as Spodoptera littoralis, Heliothis spp, Pectinophora gossypiella, insects of the order of Homoptera and Aphids in a locus, particularly a cotton plant locus, which comprises applying to the locus, in admixture, as a total mix or separately, insecticidal effective amounts of quinalphos and a pyrethroid.

Suitable application rates are 200 g-1 000 g preferably 300-750 g hectare of plant locus, the weight being the total weight of constituents a) and b), the treatment being repeated as required.

The compounds are preferably applied in the form of an aqueous spray.

The composition of the invention may be formulated in any conventional form, for example in the form of an emulsifiable concentrate, wettable powder or soluble powder, the emulsifiable concentrate form being preferred.

Solid forms may include carriers such as diatomaceous earth, talc, kaolinite, attapulgite, pyrophyllite, artificial mineral fillers based on silicon dioxide and silicates, lime, sodium sulphate decahydrate and plant material carriers such as walnut flour. Adjuvants such as wetting and dispersing agents, e.g. sodium laurylsulphate, sodium dodecyl benzenesulphonate, condensation products of naphthalene sulphonate and formaldehyde, polyglycol ethers and lignin derivatives such as sulphite liquor, may also be included in the case of wettable powders to be applied as an aqueous suspension.

Liquid forms may include non-phytotoxic diluents such as alcohols, glycols, glycolic ethers aliphatic and aromatic hydrocarbons, e.g. xylene, alkylnaphthalenes and other petroleum distillates, and ketones, e.g. cyclohexanone and isophorone.

Adjuvants such as surface active agents, e.g.

wetting and emulsifying agents such as polyglycol ethers formed by reaction of alkylene oxides with high molecular weight alcohols, mercaptans or alkyl phenols and/or alkylbenzene sulphonates may be included in emulsion concentrate forms.

Aside from the above mentioned carriers, diluents and adjuvants, other additives such as stabilizing agents, deactivators, surface adhesion improvers, anti-carrosives, defoaming agents and pigments may also be included.

Concentrate forms of the composition according to the invention generally contain from 1 to 90%, preferably 5 to 50% by weight of the constituents a) and b).

Application forms of the composition according to the invention generally contain from 0.02 to 90% preferably from 0.1 to 20% by weight of the constituents a) and b).

The compound quinalphos is a known insecticide effective in the combating of insects.

Pyrethroids are also known insecticides. We have found that the combination of pyrethroids with quinalphos has a greater than additive effect of both the constituents in combating insect pests in a locus, particularly in cotton.

The invention is illustrated by the following Examples in which all parts and percentages are by weight.

Example 1 Three different strains of cotton leaf-worm from the Aegyptian Provinces Menoufia, Behera and Alexandria have been investigated. The egg masses were collected from cotton fields from said Provinces and reared in the laboratory. When the larvae reached the fourth instar, they were given cotton leaves from cotton fields sprayed with the insecticides. The cotton leaves were given 0,3, 5,7 and 9 days after treatment of the cotton field. The cotton fields were treated as follows: Two combined concentrate mixes were prepared, by admixing 10 parts by volume Ekalux(B) (a commercially available 25% emulsion concentrate of quinalphos) and 1 part by volume Sumicidin(B) (in the form of the commercially available 20% emulsion concentrate of fenvalerate).The concentrates were diluted x 1000 and applied separately to cotton crops by knapsack sprayer (6 nozzle) at a rate of 2.4 1/ha EkaluxB and 240 cc/ha of the above Sumicidin.

The efficacy of the mixture is determined by comparing the mortality of the cotton leaf-worm larvae caused by cotton leaves treated with both the active ingredients of the combination with the mortality caused by cotton leaves treated with only one of the active ingredients. A greater than additive effect is observed. The persistent activity of the combination can also not be explained by a mere additive effect.

Example 2 Analogous results are obtained with corresponding amounts of Quinalphos + Permethrin, Quinalphos + Cypermethrin as well as with a mixture of 2.4 I/ha EkaluxO with 240 cc/ha DecisB (Decis is a commercially available 25 g/l emulsion concentrate of decamethrin).

Example 3 Emulsifiable Concentrate A composition containing 25 parts of quilalphos 1 part of permethrin 64 parts of xylene 10 parts of surfactant was prepared. The emulsifying agent was a mixture of calcium dodecylbenzene sulphonate and alkylarylpolyoxyethylenated ethanol.

The resulting concentrate can be diluted with water to give emulsions of any desired concentration.

Claims

1. An insecticidal composition comprising a) the compound of formula I,

and b) a pyrethroid.

2. A composition according to Claim 1, wherein the pyrethroid is a 3-phenoxybenzyl ester or a a-cyano-3-phenoxybenzyl ester of 3(2,2dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid, 3-(2,2-dibromovinyl)-2,2dimethylcyclopropane carboxylic acid and 4 chlorophenyl-3-methylbutyric acid.

3. A method of combating insects in a locus, which comprises appiying to the locus the compound of formula I, as defined in Claim 1 (constituent a)) and a pyrethroid (constituent b)) in an insecticidal effective amount.

4. A method according to Claim 3, wherein the application rate is 300 to 750 g/hectare of plant locus, the weight being the total weight of constituents a) and b), and the weight ratio constituent a) and constituent b) is in the range of 10:1 to 250:1.