JPH02282310A - Control of pine sawyer with beauveria bassiana fungus using yellow small pine engraver as disseminator - Google Patents

Abstract

PURPOSE:To readily and effectively control pine sawyers with Beauveria bassiana fungus using yellow small pine engravers as disseminators by releasing the yellow small pine engraver imagines having the spores of the Beauveria bassiana fungus adhered to the surfaces of the bodies thereof in a pine forest damaged with the pine engravers. CONSTITUTION:Several thousands-ten thousands imagines of yellow small pine engravers, the secondary insects for pines, and approximately 0.5cc of Beauveria bassiana fungus spores are placed in an approximately 0.5l polymer cup and slightly shaken to readily and suitably adhere the spores to the surfaces of the imagines. An approximately 1m long pile is stood in a damaged pine forest and a plate is loaded on the pile, followed by releasing the Beauveria bassiana- adhered yellow small pine engravers on the plate. Almost all of the imagines as the disseminators fly away within approximately one hour to carry the Beauveria bassiana to damaged pine trees for effectively controlling the pine sawyers and for improving to prevent the damage of the pine engravers. The release of the yellow small pine engravers is carried out three times in the oviposition period of the pine sawyers.

Description

[Detailed Description of the Invention] [Industrial Application Fields] The present invention is directed to pine wood nematode damage (academically known as pine wood nematode This relates to methods for controlling diseases.

[Background of the invention and prior art] The pine weevil damage, which is said to have first occurred in Nagasaki City in the early 20th century, has since gradually spread to other areas, and is now widespread in pine forests throughout Japan, except for Hokkaido and Aomori Prefecture. ing.

In 1980, the amount of damage caused by pine beetles nationwide reached 2,430,000 cubic meters, but after that it gradually decreased, and by 1980, it had reached 1.
The area is now 140,000 cubic meters. In 1971, it was discovered that the cause of the abnormal mass blight of these pines was the pine nematode, a violently contagious disease that was spread to healthy pine trees one after another by adult beetles of the pine beetle, causing them to become infected and die. did. Therefore, as a control method, insecticides are sprayed on pine forests during the adult development period of the pine beetle (there are aerial spraying and spraying from the ground) to prevent the spread of the pine beetle nematode. A felling and extermination method has been developed that eliminates the source of infectious diseases by cutting down damaged trees, spraying insecticides, and extinguishing longhorn beetles that live inside the damaged trees before they fly out. These two methods are still widely practiced today as basic methods for controlling pine weevil damage.

[Problems to be Solved by the Invention] However, preventive measures such as chemical spraying are restricted in consideration of the natural environment and living environment, and the places where they can be implemented are limited.

In addition, felling and exterminating trees requires a great deal of effort, so it is extremely difficult to fully implement them as the area where damage occurs is expanding. For this reason, considering the current situation where damage exceeding one million cubic meters is still occurring nationwide, there is a strong desire from a national standpoint to develop new control methods.

As mentioned above, the mainstay of conventional pine weevil damage control techniques are preventive measures such as spraying chemicals on pine forests and cutting down and exterminating damaged trees. There are methods such as injecting the insects to avoid disease and death even if they are invaded by the pine beetle, and methods that use an attractant for the pine beetle to collect and kill adult beetles. However, these other methods have their own drawbacks in terms of cost, labor, and effectiveness, and therefore serve as supplementary means to supplement the above-mentioned main methods.

Although it is not possible to increase the area of preventive chemical spraying due to environmental considerations,
It is generally agreed that due to its outstanding effectiveness, it will continue to be one of the mainstream measures against pine weevil damage. The problem is the other mainstay, extermination of felling. This method becomes fully effective only when all of the damaged trees in a certain area are almost completely exterminated. Until the early 1970s, when the damage occurred was limited to areas with relatively warm climates, so-called buroku-heavy areas, it was necessary to expend a large amount of manpower within a limited area. We were able to perform sufficient processing and achieve appropriate effects. However, now that the damage has become almost nationwide, combined with changes in the social situation such as labor shortages in mountain villages, it is necessary to discover and cut down all the damaged trees, and to remove all the pine trees that live there. The situation has become almost impossible to kill longhorn beetles manually. Unless the fundamentally important measures of eradicating the sources of infectious diseases are effective, there is no hope of fundamentally easing the pine weevil damage.

The problem that the present invention aims to solve is based on a completely new idea, and it overcomes the drawbacks of conventional methods of felling and removing damaged trees, which rely on manual labor for most of the work, making them ineffective. To more simply and effectively exterminate the pine beetle in trees.

Through long-term research on pine beetles, a considerable amount of knowledge has already been accumulated regarding the existence of natural enemy microorganisms of pine beetles, such as Beauveria fungi, and their insecticidal powers. On the other hand, there is a group of insects consisting of several dozen species called secondary borers of pines. These insects cannot reproduce by parasitizing healthy pines; adults are attracted to the specific odor emitted by pines that have weakened or died for some reason, and fly to the tree to lay eggs and destroy the bark. It is already well known that the survival of the species is ensured by the development of larvae only at the bottom. The pine beetle is also a member of this group of insects, but it has become an important pest because it transmits the pine beetle.

Beauveria fungi are insect-parasitic filamentous fungi that are fairly widely distributed within the Pinaceae family, but in the natural world they are rarely seen parasitizing and killing insects under the bark of pine weevil-infested trees. This is probably because the spores of this fungus have difficulty penetrating under the bark under natural conditions. It is known that direct inoculation of Beauveria fungus spores to longhorn beetles larvae has a significant insecticidal effect.

Beauveria fungi prefers moisture and is extremely sensitive to ultraviolet rays, so the conditions under the bark are ideal. Therefore, if the spores of this fungus can be coated and penetrated under the bark of a parquet tree by some method, the probability of infection and death of the praying mantis larvae during its long development period under the bark is expected to be quite high. Ru.

The present inventors have conducted extensive research from the above viewpoints and have accomplished the present invention. That is, an object of the present invention is to provide an effective method for introducing Beauveria fungi, which is effective for controlling pine beetle, under the bark of pine trees, thereby preventing damage caused by pine weevil.

[Means for Solving the Problems] To this end, the present inventor uses a secondary pine insect other than the pine beetle to introduce spores under the bark. The insect best suited for this purpose must satisfy the following conditions, and the yellow bark beetle was selected as a result.

(A) The insect must be of a type that burrows under the bark immediately after the adult insect escapes.

(B) The type should be easy to artificially propagate in large quantities.

(C) It must be a species that is universally distributed in areas affected by pine beetles.

(D) It must be a species that does not have any negative impact on healthy trees even if there are a large number of adult insects.

The present invention was achieved by further studying and developing the following technology under the fundamentally required conditions as described in 2.

(1) Mass proliferation of Beauveria fungus spores (2) Development of a method for mass rearing of yellow bark beetles (3) Development of a method to easily and appropriately attach Beauveria fungus spores to adult yellow bark beetles Regarding (1) above, ,
There is a known method for propagating this bacterium, and by applying it on a large scale, we were able to propagate it in large quantities.

Regarding (2) above, by adding the inventors' ingenuity to the well-known facts regarding the life history and ecology of yellow bark beetles, we have established a practical mass-breeding method that efficiently utilizes small logs with red pine bark. did. By this method, we were able to increase the number of individuals tenfold every month and a half.

Regarding (3) above, it was confirmed that when Beauveria fungus spores are attached to adult yellow bark beetles, the insects become sick and die in 3 to 7 days, and the spores multiply on the insect bodies. Note that if the initial amount of adhesion is too large, the walking and flying behavior of the adult insects will become abnormal, so it is desirable to consider the necessary and sufficient amount of adhesion.

The characteristics of the method of the present invention, which was developed based on the knowledge as described above, is that Bauveria bassiana
) The main purpose of this method is to transmit adult yellow bark beetles with spores attached to their body surfaces into forests affected by pine weevil.

In the present invention, in order to attach Beauveria bacteria to adult yellow bark beetles, for example, several thousand to 10,000 adult yellow bark beetles are added to about 0.5 liters of polycup.
．． By adding 5 cc of Beauveria fungus spores and gently shaking it, the spores can be attached to the surface of the adult insect body very easily and appropriately.

The relationship between the volume and overlay of adult yellow bark beetles reared in large quantities was confirmed by filling a graduated cylinder to approximately 1,000 adults per Icc, making it easy to determine the overlay of yellow bark beetles.

For example, as an adult method in the Pinaceae, set up a 1m stake in the damaged Pinaceae, place a board on top of it, and use the above method to attach the Beauveria fungus to the adult yellow bark beetle. Most of the adults will disperse over time. Distance traveled by adult yellow bark beetles from the release point I
As for ll, there is a record of another similar bark beetle that can fly 300 meters, and it is thought that the yellow bark beetle also flies at this distance.

The adult stage of the yellow bark beetle is set to coincide with the spawning season of the pine beetle, and it is best to conduct the test three times during that period.

[Examples] The present invention will be described below based on examples, but is not limited to these examples.

Example 1 [Indoor test] Twenty-eight red pine logs (50 cm in length, 5 to 10 cm in diameter) felled and cut in May 1988 were propped up against a rearing box, and 50 mature female adult Japanese longhorn beetles were grown after mating. The eggs were allowed to lay on the head for two weeks. This was divided into approximately five equal parts, one of which was designated as an untreated plot, and the remaining four were treated with approximately 1,000 yellow bark beetle adults attached to Beauveria fungus spores. After that, when we investigated the mortality status of longhorn beetle larvae caused by Beauveria bacteria over time, we found that no mortality occurred in the untreated area, but in the treated area, 14% died at the 10th day of release, 27% at the 30th day, and 27% at the 40th day. The mortality rate of longhorn beetles gradually increased to 36%, and eventually almost 100% died.

Example 2 [Outdoor screened room test] In July 1988, 40 raw red pine logs (length 1.8 +
5 to 18 cm in diameter) were set up in an open-air screened room, and 70 mature female adult beetles were released and allowed to lay eggs for 2 weeks. These were placed in four open-air screened rooms of 50 mesh size through which yellow bark beetles could not pass, and 200 to 1000 yellow bark beetles with Beauveria fungi were released per square meter of surface area of the logs. 2 per square meter
Mortality rate of 00 adult beetles released: 99%
In all other areas, the rate was 100%, indicating an extremely excellent pesticidal effect.

[Effects of the invention] In early summer, pine beetles carrying pine beetle fly out from trees damaged by pine weevil and spread new damage. Therefore, cutting down and exterminating the damaged trees, which are the source of the next damage, has been carried out in the past by cutting down the trees and spraying them with chemicals to kill the pine beetles that live there before they fly out. However, as mentioned above, it has become difficult to fully implement the process, as the series of manual tasks such as finding damaged trees, felling them, cutting them down, and treating them with chemicals requires a great deal of labor and expense.

According to the present invention, the yellow bark beetle, which is a secondary insect of pines, is used as a carrier to transport the Beauveria fungus under the bark of the damaged tree, thereby effectively eliminating the pine bark beetle.
Since it can provide a new method for effective control, it will greatly contribute to improving the control of pine weevil damage. In particular, the method of the present invention is superior in the following points compared to the current method of exterminating tree felling using chemicals, and in the future, the method of the present invention will become the mainstay for controlling pine weevil damage along with aerial spraying of chemicals for prevention. I think that the.

The basic idea of the present invention, which uses bark beetles to transport natural enemy microorganisms under the tree bark to control pests, is applicable not only to the control of pine weevil damage, but also to all pests that breed under the bark. Therefore, it is expected that it will be used in the future as a new pest control method.

(1) Yellow bark beetles naturally explore weakened and dead pines and burrow under the bark, so there is no reduction in effectiveness due to oversight or lack of attention by humans.

(2) Because the Beauveria fungus is introduced under the bark of the tree from the early stages of development of the pine beetle larvae, infection occurs throughout the subsequent long development period, ultimately resulting in an insecticidal effect greater than that of general chemical treatment. .

(3) By the method of the present invention, the Beauveria fungus that is introduced into the damaged pine forest can be expected to take root even afterward and maintain its effect for a long time, which is the greatest advantage of using natural enemies.

(4) Beauveria fungi and yellow bark beetles are organisms that have lived in the pine forests of Japan since ancient times, and even if they are used in this way, there will be no negative impact on the ecosystem and living environment, which is a concern when spraying chemicals. No worries.

(5) Since manual work such as felling, which is required in conventional methods of felling and exterminating damaged trees, can be omitted, labor costs can be significantly reduced, so it is economically possible to prevent the pine beetle from escaping from damaged trees. can. Large areas can be efficiently controlled by release using helicopters.

Claims (1)

[Claims] Beauveria bassiana
) A method for controlling the pine beetle using the Beauveria fungus using the yellow beetle as a propagator, which is characterized by releasing adult yellow bark beetles with spores attached to their body surfaces into forests damaged by the pine beetle.