JPS639485B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for killing overwintering eggs of the long-eared longhorn beetle laid within the trunks of mulberry trees. More specifically, the present invention relates to a novel method for controlling the mulberry tree beetle, which is characterized by spraying a composition containing an organophosphorus insecticide and kerosene as essential ingredients during the dormant period of mulberry trees. The purpose of this invention is to provide a new control method that can reliably control the overwintering eggs and larvae of the long-eared longhorn beetle in an extremely safe and low-dose manner. Over the past few years, there have been frequent cases of the yellow-eared longhorn beetle occurring abnormally in mulberry orchard areas, mainly in the Kanto region, and destroying the mulberry orchards, and effective and appropriate control methods have been sought. The present invention meets this need and has extremely important practical significance. The long-eared beetle has been well-known as a pest of mulberries since ancient times, but its damage has not been much of a problem. The reason for this is that this pest mainly occurs in areas west of Yamanashi and Nagano, and its ecology is that adults emerge and escape from June to July, and all eggs laid hatch in the summer and overwinter as larvae. This is because almost complete control was achieved by spraying an organic phosphorus insecticide with a strong larvicidal effect diluted with water to 0.25-0.5% active ingredient from late autumn after the completion of sericulture to early spring before the start of sericulture. The reason why the yellow-eared mantis, which had no problems in the past, has recently appeared frequently in the Kanto region is thought to be due to some change in the ecology of the brown-eared mantis. In other words, the yellow-crowned mantis, which has been prevalent in the Kanto region in recent years, has a peak emergence period from September to October, unlike conventional ones, and although some of the eggs laid hatch, the majority remain in the egg state and overwinter. It is known that this has changed. The present inventors focused on changes in the overwintering ecology of the Yellow-rumped Flycatcher, and investigated the effect of chemicals on the overwintering eggs of the Yellow-rumped Flycatcher laid within the trunks of mulberry trees. o,o-dimethyl o-
(3-Methyl-4-nitrophenyl) thiophosphate (hereinafter abbreviated as MEP) and o,o-dimethyl o-{3-methyl-4-(methylthio)phenyl}thiophosphate emulsion diluted with water can be sprayed on mulberry trees. It was found that this method had extremely poor ovicidal power against the overwintering eggs of the long-eared longhorned beetle, and that it hardly served the purpose of control. In general, boring insect pests, even if their population density is low, cause significant damage to the inside of the tree trunk and cause death, so complete control is required. Therefore, we conducted a search for an insecticide with a strong ovicidal effect on the eggs of the yellow-throated mantis for the purpose of complete control, but the conventional method of diluting an emulsion with water and spraying it did not have a satisfactory ovicidal effect, and the active ingredient 2.5-5%
Even under high concentration conditions, the ovicidal effect is 80% to 90%.
However, the goal of complete control could not be achieved. However, completely unexpectedly, when spraying a preparation containing an organophosphorus insecticide in kerosene, a surprising increase in ovicidal efficacy was observed for the eggs of the yellow-spotted beetle laid within the trunks of mulberry trees. 1/20 in comparison
They found that the following amounts of active ingredients can kill eggs 100%. As is well known, kerosene alone has no ovicidal effect on the overwintering eggs of the long-eared longhorn beetle, but it is an extremely surprising fact that when it is combined with an organophosphorus insecticide, it exhibits a surprising synergistic effect. It was hot. Therefore, in order to put this knowledge into practical use, the present inventors investigated the timing of spraying kerosene and its effect on phytotoxicity of mulberry plants and silkworm offspring, and found that if kerosene is sprayed during the dormant period of mulberry plants, it will not cause chemical damage and will be effective against silkworm offspring. The present invention was completed after confirming the fact that there is no adverse effect even if By carrying out the present invention, the overwintering eggs of the mulberry leaf beetle are completely killed, and the overwintering larvae are also killed at the same time. In addition, the early pests of mulberries, such as the mulberry scale, the mulberry weevil, and the mulberry weevil, are also controlled as a secondary control, so the present invention is practical not only in terms of saving labor in spraying pesticides, but also in terms of reducing the amount of chemicals used. have value. The present invention may be applied only once at any time from late autumn after the completion of sericulture to before the budding of mulberries, but no harm will occur even if the mulberry is sprayed 2 to 3 times during the dormant period of the mulberries. Furthermore, since the application targets the main stem and branch stems, feeding mulberry leaves that have sprouted from the branch branches will not have any adverse effects on silkworms. The amount of the ovicidal composition of the present invention to be sprayed is adjusted appropriately depending on the size of the mulberry tree, but it is generally 20 c.c. to 150 c.c. per tree.
cc is appropriate, and the blending ratio of organophosphorus insecticide to kerosene is preferably 0.2% to 2.0%. Examples of organophosphorus insecticides used in the ovicidal composition of the present invention include o,o-dimethyl o-4-cyanophenyl thiophosphate (hereinafter abbreviated as CYAP), 2-methoxy-4H-1,3, Examples include 2-benzodioxaphosphorine-2-sulfide {hereinafter abbreviated as salithion (registered trademark of Sumitomo Chemical Industries, Ltd.)} and MEP. Only one type of organophosphorus insecticide may be used in the composition of the present invention, but it goes without saying that two or more types may be used in combination. When preparing the ovicidal composition according to the present invention, some types of organophosphorus insecticides may not dissolve in kerosene as they are, so in such cases xylene, aromatic high boiling point naphtha solvents may be used. Ketones such as cyclohexanone, methyl isobutyl ketone, isophorone, and other solvents for agricultural insecticides are added to aid in dissolution. In addition, a surfactant may be used for the same purpose.
Use species or mixtures of two or more species. Furthermore, the inventors have found that the ovicidal composition of the present invention does not necessarily need to be in the form of a solution, and that a water-in-oil emulsion having kerosene as a continuous phase is equivalent to a kerosene solution. The effect of However, a water-diluted solution of a kerosene emulsion containing an organic phosphorus insecticide and an emulsifier in kerosene is significantly less effective and is not practical. The kerosene used in this invention is JIS standard type No. 1 and 2.
For practical purposes, No. 1, commonly known as white kerosene, is preferred. White kerosene is defined as having a distillation point of 280°C or lower and a drawdown point of 35°C or higher. Next, the present invention will be specifically explained with reference to Examples and Reference Examples, but the present invention is not limited to these. Example 1 Formulation method (1) After dissolving 1 part of MEP in 2 parts of xylene, white kerosene 97%
1% of MEP and dissolve with stirring to make a 1% MEP oil. (2) After dissolving 1 part of CYAP in 5 parts of cyclohexanone,
Add 94 parts of white kerosene and dissolve with stirring to obtain a 1% oil solution. (3) Dissolve 1 part of salithion in 10 parts of isophorone, then add 89 parts of white kerosene and dissolve with stirring to make a 1% oil solution. (4) 1 part MEP, 2 parts xylene, 50 parts white kerosene, and sorbitan monooleate (trade name Span 80)
Add 2 parts and stir to dissolve, then add 45 parts of water and disperse with a sand grinder (manufactured by Igarashi Kikai Seizo Co., Ltd.) at 2000 rpm for 1 hour to obtain MEP1%.
Make it a water-in-oil emulsion. Reference example 1 Effect of high-concentration emulsions of various insecticides on the ovicidal effect of high-concentration insecticides (1) Test method Mulberry branches with a diameter of 3 cm and a length of 30 cm were placed in a frame (60 cm x 120
cm x 60 cm) for 2 days to collect the spawned mulberry branches. Each emulsion was diluted with water to a concentration of 5% to 0.3% and spawned with an emulsion of 50 c.c. per 3 mulberry branches.
Sprayed evenly with a small hand sprayer.
After air-drying and storing at a constant temperature of 25°C for 30 days, the mulberry bark was peeled off and the hatching status of the mulberry beetle eggs was investigated. (3) Test results

[Table] As shown in the table above, 5 times the salithion emulsion 5 times solution
% solution and 5% solution of 10x CYAP emulsion are not perfect as the unhatched egg rate is about 80%. *Unhatched egg rate = number of eggs + number of larvae in eggs / number of surveyed individuals x 100 Example 2 Effect of ovicidal kerosene formulation containing insecticides on stag beetles (1) Test method On mulberry branches where eggs were laid in the same manner as in Reference Example 1, Example 1
0.5%, 0.25%, formulated according to the formulation method of
A undiluted solution of oil containing 0.13% insecticidal ingredients was applied uniformly to three mulberry branches at 50 c.c. using a small hand sprayer. After air-drying and storing at a constant temperature of 25°C for 30 days, the bark of the mulberry was peeled off and the hatching status of the mulberry beetle eggs was investigated. (2) Test results

【table】

[Table] As shown in the table above, white kerosene alone has no ovicidal effect, but white kerosene containing 0.5% to 0.13% insecticidal ingredients
By containing it, a high effect is exhibited. Note that the unhatched egg rate was calculated using the formula described in Reference Example 1. Example 3 Effect of insecticide-containing kerosene preparations on controlling the Japanese longhorn beetle (1) Test method Each insecticidal ingredient was added at 2.0% to 0.5% to a mulberry tree (variety: improved Nezugaeshi, 7th grade) in Kumagaya City, Saitama Prefecture.
A 5% emulsion of oil, kerosene, and MEP emulsion containing 75% per plant was sprayed at 75 c.c. The test scale was 6 strains per drug group and 2 replicates. The timing of spraying was once each on January 23, 1954 and March 2, 1954 in the oil area, and on March 2 for MEP emulsion and kerosene alone. The egg rate in the tree trunk as of January 23rd was 63.1.
It was %. The survey was carried out from April 16th to 21st by cutting out mulberry plants and determining the hatching status under the bark and whether the larvae were alive or dead. (2) Test results

【table】

[Table] Number of dead insects of eggs + larvae in eggs + larvae
Mortality rate =

Claims (1)

[Claims] 1. A method for ovicidating the long-eared longhorn beetle, which comprises spraying a kerosene composition containing an organophosphorus insecticide during the dormant period of mulberry trees.