Chapter 18 Seventeen other roads

Now, we are standing at the intersection of two roads.But these two roads are completely different, and they are very different from the familiar road in Robert Frost's poetry.The road we've been driving for so long can easily be mistaken for a comfortable, flat, superhighway on which we can travel at high speed.In fact, disaster awaits at the end of the road.Another fork in the road - a "less traveled" fork - offers us our last and only chance to keep our planet. Ultimately, it's up to us to make our own choices.If after long suffering we have finally become convinced of our "right to know," if our heightened awareness concludes that we are being asked to undertake a foolish and frightening venture, then we are told to fill our bodies with toxic chemicals. To fill our world, we should never take the advice of such men again; we should look about us, and discover what road still leads us.

Indeed, a wide variety of workarounds are required to replace chemical control of insects.Some of these methods have been put into use with brilliant results, others are in the stage of laboratory experiments, and still others exist only as ideas in the minds of imaginative scientists. Wait for the moment to jump into the experiment.All of these approaches have one thing in common: they are biological solutions.These approaches to insect control are based on an understanding of the structure of dialogue between the organism and the entire living world on which it depends.Various specialists representing the vast field of biology—entomologists, pathologists, geneticists, physiologists, biochemists, ecologists—are bringing their knowledge and their creative inspiration to Contribute to an emerging science - biological control.

Biologist John Hopkins said: "Any science is like a river. It has a hazy and unknown beginning; sometimes it flows calmly, sometimes it rushes fast; it both dries up. , there are times when the water rises. It gains momentum by the hard work of many investigators, or when other streams of thought feed it. It is deepened and deepened by gradually developed concepts and generalizations. Widen". Judging from the modern situation of biological control science, its development is in line with Johns Hopkins' statement.In the United States, the science of biocontrol began in the twilight a century ago, when the first attempts to control the natural pests of insects that had been found to be a nuisance to farmers had sometimes progressed slowly, or stopped altogether; but it Gain acceleration and momentum from time to time under the impetus of outstanding achievements.When people working in applied entomology were dazzled by the splendor of the new insecticides of the 1940s, they discarded all biological methods and put their feet on the treadmill of "chemical control." at this time, the river of biological control science is drying up, and the goal of making the world free from insects is gradually receding.Now, at a time when, through the careless and arbitrary use of chemicals, we have posed a greater threat to ourselves than insects, the rivers of biological control science are flowing again, aided by new sources of thought.

Some of the most fascinating new methods are those which seek to turn an insect's power against itself—to exploit the tendency of the insect's vital forces to destroy itself.Most impressive of these achievements is the "male sterilization" technique developed by Dr. Edward Knipling, head of the USDA's Entomological Research Institute, and his collaborators. About twenty-five years ago, Dr. Knipling astonished his colleagues by proposing a unique method of controlling insects.He theorized that if it were possible to render large numbers of insects sterile and release them so that under certain circumstances these sterile males would outcompete normal wild males, then by repeatedly releasing Fertilizing males may produce eggs that cannot hatch, and the population becomes extinct.

Bureaucratic indifference to the suggestion made scientists skeptical, but Dr. Knipling stuck with the idea.A major problem to be solved before this idea can be put to the test is the need to find a practical way of rendering insects sterile.Theoretically, the fact that insects may be sterile due to X-ray exposure has been known since 1916, when an entomologist named G. A. Lange reported this infertility in relation to the tobacco beetle. breeding phenomenon.In the late twenties, Hermann Müller's pioneering work on X-ray-induced mutations in insects opened up a whole new realm of thought; by the middle of this century, many researchers were reporting at least a dozen species of insects Sterility occurs under the action of gamma rays.

However, these are indoor experiments, far from practical application.Around 1950, Dr. Knipling began an intensive effort to turn insect sterility into a weapon against the screwworm, a major pest of livestock in the southern United States.The fly lays its eggs on the exposed wounds of all bleeding wounded animals.The hatched larva is a parasite that feeds on the flesh of its host.A mature steer can die within 10 days of a severe infection, and livestock losses in the United States are estimated at $40 million a year.Estimating the loss of wildlife is difficult, but it is certainly enormous.The scarcity of deer in certain areas of Texas is attributed to the screwworm.This is a tropical or subtropical insect found in South and Central America and Mexico, and in the United States they are generally confined to the Southwest.Around 1933, however, they accidentally found their way into Florida, where the climate allowed them to survive the winter and establish populations.They even pushed into southern Alabama and Georgia, and the livestock industry in the southeastern states soon suffered losses as high as $20 million a year.

A great deal of information on the biology of the screwworm had been gathered during those years by scientists at the Texas Department of Agriculture. In 1954, after conducting some preliminary field experiments on Florida Island, Dr. Knipling was ready to conduct larger experiments to test his theory.To this end, in an agreement with the Dutch government, Knipling went to Curacao, an island in the Caribbean Sea at least 50 nautical miles away from the mainland. Experiments began in August 1954. Screwworms, grown and sterilized in a Florida Department of Agriculture laboratory, were airlifted to Silasaw Island, where they were dropped by aircraft at a rate of 400 square miles per week. go out.The number of egg masses laid on the experimental rams began to decrease almost immediately, just as quickly as they increased.Within only seven weeks of the start of this spreading operation, all eggs laid became sterile.Soon no egg populations, whether sterile or normal, will be found again.Screw flies have indeed been eradicated from Curacao.

The famously successful experiment in Curacao has sparked a desire among Florida livestock breeders to use the technology to keep them safe from screwworms.The difficulties are relatively greater in Florida, though—it's 300 times the size of tiny Curacao; in 1957, the USDA and the state of Florida jointly funded a screwworm eradication effort.The plan involves producing approximately 50 million screw flies per week in a purpose-built "fly factory," and involves flying five to six hours a day on predetermined routes with twenty light aircraft, each with 1,000 cartons, each containing 200 to 400 x-rayed screwworms.

The cold winter of 1957-1958, gripping northern Florida with extreme cold, was an unexpectedly good time to start the project, as screwworm populations were dwindling and confined to a small area.At that time, it was considered that it would take 17 months to complete the plan, and 3.5 billion screw flies would be raised artificially, and the sterile flies would be scattered all over Florida, Georgia and Alabama.The last possible infection of animal wounds by screwworms occurred in January 1959.Over the next few weeks, the screwfly fell for the trap.Since then, no trace of the screwfly has been found.The eradication of the screwworm has been accomplished in the southeastern United States—a shining testament to the value of scientific ingenuity, combined with rigorous basic research, perseverance, and determination.

Now, an isolation barrier in Mississippi is working to keep the screwworm from resurging from the Southwest, where it is firmly confined.There, the plan to eradicate the screwworm will be very difficult because of the size of the area and the possibility of re-invasion from Mexico.While this is the case, the stakes are high, and it appears that the Department of Agriculture's thinking is to at least keep screwworm populations at a low enough level to try them out soon in Texas and other parts of the Southwest where screwworms are rampant certain plans. The brilliant victory against the screwfly has spurred great interest in applying the method to other insects.Of course, not all insects are suitable subjects for this technique, which relies heavily on the finer details of the insect's life history, population density and response to radiation.

Trials have been carried out by the British in the hope that this method can be used to eradicate the Rhodesian fly fly.The insect has spread across a third of Africa, threatening human health and hampering livestock rearing in 4.5 million square miles of wooded grasslands.The habits of the fly fly are quite different from those of the screwworm, and although the fly fly can be rendered sterile by radiation, there are some technical difficulties to be solved before this method can be applied. The British have experimented with the susceptibility of a large variety of insects to radioactivity.US scientists have had some promising initial results with the watermelon fly and the oriental and mediterranean fruit fly in indoor experiments in Hawaii and in field experiments on remote Rota Island.Trials were also conducted on both grain borers and sugarcane borers.There is a possibility that insects of medical importance may also be controlled by sterility.When a Chilean scientist has pointed out that malaria-transmitting mosquitoes escape the treatment of insecticides and still exist in his country, only the release of sterile male ants can provide the devastating blow to eradicate them. The apparent difficulty of achieving sterility by radioactivity has compelled the search for an alternative, easier method of achieving the same result, and there has now been a surge of interest in chemical sterilizers. Scientists working in a Department of Agriculture laboratory in Orlando, Fla., are now using chemicals mixed into food to render houseflies sterile in the laboratory and in some field experiments. In a 1961 experiment at Keys Island, Florida, the housefly colony was wiped out in as little as five weeks.Although houseflies from neighboring islands later repopulated locally, the experiment was successful as a pilot.The Department of Agriculture's excitement at the prospect of this approach is understandable.In the first place, as we have seen, the housefly has now become practically uncontrolled by insecticides.There is no doubt that a whole new approach to insect control is needed.One of the problems with using radioactivity to create sterile insects is that not only does it require breeding the insects, but you also have to release a larger number of sterile males than there are in the wild.This can be done with the screwworm, which is not actually a very plentiful insect.In the case of the housefly, however, the release of more than twice the original population of flies may be met with fierce opposition, even if the increase in the housefly population is only temporary.In contrast, a chemical sterilant can be mixed with insect bait and introduced into the natural environment of the housefly; the insects fed the drug become sterile, and eventually the sterile The housefly has gained the upper hand and the insect will cease to exist by laying eggs. Experiments on the sterile effects of chemicals are much more difficult than experiments on the toxicity of chemicals.It takes 30 days to evaluate a single chemical -- although many experiments can be run at the same time.Between April 1958 and December 1961, several hundred chemicals were screened for their possible sterile effects in Oland's laboratory.It appears that the USDA has happily found a handful of promising chemicals in the middle. Now, other labs at the Department of Agriculture are continuing to study the problem, experimenting with chemicals to kill stable flies, mosquitoes, boll weevils and various fruit flies.All of this is currently experimental, but the work on chemical sterilizers has come a long way in the few short years since research began.In theory, it has many attractive properties.Effective chemical insect sterilizers "could easily outperform the best existing insecticides," Dr. Knipling said.Imagine this, a colony of a million insects multiplying fivefold with each passing generation.If a pesticide kills 90 percent of the insects in each generation, 125,000 insects remain after the third generation.In contrast, a chemical that caused sterility in more than 90 insects might leave only 125 insects in the third generation. There is also a downside to this method, as chemical sterilizers also include some extremely potent chemicals.But fortunately, at least in these early stages, most of those working on chemical infertility seem to be concerned with finding safe drugs and safe ways to use them.Nevertheless, demands are heard everywhere for the spraying of these sterile chemicals from the air—for example, to coat leaves chewed by gypsy moth larvae.It would be extremely irresponsible to attempt such a thing without thoroughly researching the dangerous consequences of such an approach in advance.If the potential hazards of chemical sterilizers are kept in our minds from time to time, we will soon find that our difficulties and annoyances are greater and greater than those caused by pesticides today. Sterility agents currently being tested can generally be divided into two groups; both are extremely interesting in their mode of action.The first type is closely related to the life process or metabolism of cells, that is, their properties are very similar to the substances needed by cells or tissues, so that the organism "mistakes" them as real metabolites and uses them in its normal growth process. try to combine them.However, the similarity is wrong in some details, and the cellular process comes to a standstill.Such chemicals are called antimetabolites. The second category includes those chemicals that act on chromosomes, which may act on genetic chemicals and cause chromosomes to divide.This class of chemical sterilizers is the alkylating agent, which is a very powerful chemical substance that can cause severe damage to cells, damage chromosomes, and cause mutations.Dr. Peter Alexander of the Chester Pitty Institute, London, is of the view that "any alkylating agent that is effective in sterility in insects is also a mutagen or carcinogen." Dr. Alexander feels something like this Any use of chemicals for insect control would be "highly objectionable".It is hoped, then, that the present experiments will not be aimed directly at the practical use of these particular chemicals, but will lead to other discoveries which will be safe and highly specific in their insect targets. specificity. There are still some very meaningful ways in the current research, that is, to use the life characteristics of insects themselves to create weapons to destroy insects.Insects themselves produce a wide variety of venoms, attractants and repellants.What is the chemical nature of these secretions?Can we use them as selective insecticides?Scientists at Cornell University and elsewhere are trying to discover answers to these questions by studying the defense mechanisms many insects use to protect themselves from predators and working to resolve the chemical structure of insect secretions.Other scientists are working on what is known as the "youth hormone," a potent substance that prevents insect larvae from mutating until they reach a certain stage of growth. Perhaps the most immediately useful result in pioneering the field of insect secretions was the invention of attractants, or attractants.Here again, nature points the way forward.The gypsy moth is a particularly fascinating example.This female moth is too heavy to fly. She lives on or near the ground. She can only flap her wings between low plants or climb up tree trunks.The male moth, on the other hand, is a good flyer, able to fly from great distances, attracted by the scent released by a special gland in the female.Entomologists have exploited this phenomenon for many years, painstakingly extracting this sex attractant from female moths.It was then used to trap male moths during insect population surveys along the fringes of the insect's range.However, this is an extremely expensive method.And regardless of the reported infestation in the northeastern states, there are not actually enough gypsy moths to make the material, so hand-crafted female pupae have to be imported from Europe, sometimes each pupae Up to half a dollar.However, after years of trying, Department of Agriculture chemists have recently succeeded in isolating the sex attractant, a huge breakthrough.This discovery was followed by the success in preparing a very similar synthetic substance from components of sea fox oil that not only fooled the male moths, but had nearly the same properties as natural sex attractants. seductive ability.Just a milligram (1/1000 gram) of this substance in a trap is enough to be an effective bait. All this goes well beyond scientific research, as this new, economical "gypsy moth bait" may have applications not only in insect surveys, but also in insect control.Some substances that may have a stronger decoy capacity are now being tested.In what might be called a psychological warfare experiment, the attractant is made into particulate matter and dispersed by aircraft.The purpose of this is to confuse the male moth, thereby changing its normal behavior. Under the turmoil of this attractive smell, the male moth cannot find the trace of the real smell that can lead to the female moth.Further experiments with this attack on insects are being conducted to trick the male moth into trying to mate with a fake female.In the laboratory, male gypsy moths have attempted to mate with wood chips, worm-shaped objects, and other small, inanimate objects that are suitable for feeding gypsy moth attractants.Could exploiting insects' courtship instincts to render them sterile actually be used to reduce survival in tested populations?Zhun is an interesting possibility. Gypsy moth baits are a synthetic insect attractant, though others may soon follow.A number of agricultural insects are now being investigated for their effect on artificially imitated attractants.Encouraging results have been obtained in studies of Hessian fly and tobacco stag worm. Attempts are now being made to control some species of insects with mixtures of attractants and poisons.Government scientists once created an attractant called methyleugenol and found it invincible against the oriental fruit fly and the watermelon fly.In tests on Bonin Island, 450 miles south of Japan, the attractant was combined with a poison.Small pieces of fiberboard are impregnated with these two chemicals, which are then airborne over the entire island to lure and kill the male flies.This "male eradication" program began in 1960; a year later, the Department of Agriculture estimated that more than 99 percent of the flies had been wiped out.A method such as that employed here appears to have demonstrated its superiority over the old-fashioned hype of insecticides.The organophosphorus poison used in this method is confined to the fibrous slab, which cannot be eaten by other wild animals; moreover, its residue will disappear quickly, so it will not be harmful to soil and water. cause potential pollution. However, not all communication links in the insect world are achieved by means of smells that produce attractive or repelling effects.Sound can also be a means of alarm or attraction.The continuous ultrasonic waves emitted by bats in flight (which act like a radar system to guide it through the darkness) can be heard by some moths, allowing them to avoid being caught.The flapping of the parasitic fly's approach is a warning to the sawfly larvae, causing them to flock in self-defense.On the other hand, the sounds made by insects that grow on trees enable their parasites to find them; likewise, to male mosquitoes, the fluttering of female mosquitoes is as melodious as the song of a siren. If so, what gives insects this ability to discern and respond to sounds?Although still in the experimental stage, this research is very interesting. By playing recordings of the flying sounds of female mosquitoes, it has achieved initial success in luring male ants. The male mosquitoes were lured to a charged electric grid and killed.Trials in Canada using the repelling effect of sudden bursts of ultrasonic waves against grain borers and cutworms.Two authorities on animal sounds, Professors Hubert Frings and Marpole Frings of the University of Hawaii, believe that only the right key can be found to unlock the existing understanding of the production and reception of insect sounds. With a vast repository of knowledge, field methods for using sound to influence insect behavior can be established.Both of them are famous for their discovery that starlings fly away in panic when they hear a recording of the exclamation of one of their kind; important truth.The possibility looks quite achievable to industry veterans, as at least one major electronics company is preparing to provide a laboratory for insect experiments. Sound is also being experimented with as a directly destructive factor.In an experimental pond, ultrasound would kill all mosquito larvae; however, it also killed other aquatic organisms.In another experiment, blowflies, wheat worms and yellow fever mosquitoes were killed within seconds by ultrasonic waves generated by the air.All these experiments are just the first steps toward a whole new concept of controlling insects, and the miracle of electronics will one day make these methods a reality. New methods of biological control against insects are not just a matter of electronics, gamma rays, and other inventions of human ingenuity.Some of these methods are ancient and are based on the belief that insects, like humans, are susceptible to disease.Bacterial contagion can devastate insect populations, as the plague did to man in ancient times; during viral outbreaks, insect colonies become sick and die.Diseases in insects were known before the time of Aristotle; silkworm disease appeared in medieval poetry; and it was the study of this insect disease in silkworms that led Pasteur to discover contagion for the first time. disease principles. Insects are not only infested by viruses and bacteria, but also by fungi, protozoa, microscopic worms and other small organisms in the world of tiny life invisible to the naked eye. This includes organisms that cause disease, but also those that remove waste, fertilize the soil, and participate in countless biological processes like fermentation and digestion.Why can't they help us in controlling insects? The first person to conceive of such a use of microorganisms was a zoologist Ily Mechnikov in the nineteenth century.Throughout the latter decades of the nineteenth century and the first years of the twentieth century, ideas about microbial control slowly took shape.The first evidence that introducing a disease into an insect's environment so that the insect could be controlled came in the late 1930s when milk disease, milk disease, was discovered and exploited in the Japanese beetle. It is caused by spores belonging to the genus Bacillus.As I noted in Chapter 7, this classic example of bacterial control has long been exploited in the eastern United States. Now, great hopes are pinning on experiments with another bacterium, Bacillus salingia, first discovered in the German province of Salingia in 1911, where it was found to cause eczema. Fatal sepsis of larvae.The strong killing effect of this bacterium is by means of poisoning, rather than disease.In the vigorous shoots of this bacterium, together with the spores, special crystals of a protein are formed which are very toxic to the larvae of certain insects, especially butterflies like the butterfly.Shortly after the larva eats grass blades laced with the poison, it becomes paralyzed, ceases to feed, and dies soon after.From a practical point of view, it is of course advantageous to stop eating immediately, because as soon as the pathogen is applied to the field, the damage to the crops stops immediately.Mixtures containing spores of Bacillus salingia are now being produced by companies in the UK under various trade names.Field trials are underway in several countries: against cabbage butterfly larvae in Germany and France, against autumn fabric worms in Yugoslavia, against tent caterpillars in the USSR.In Panama, where trials began in 1961, the bacterial insecticide might solve some serious problems facing banana growers.There, the root borer is a major pest of banana trees because it damages the roots of the banana tree, making it vulnerable to wind blowing.Dieldrin, the only chemical effective against borers, has now set off a chain reaction of disaster.Piercers are enjoying a revival right now.Dieldrin also wiped out some important predatory insects, and thus caused an increase in the leaf tortrix, a small, hard-bodied moth whose larvae chew up the surface of bananas.There is reason to hope that the new bacterial insecticide will wipe out both leaf tortrix and borer without disturbing natural controls. Bacterial insecticides may be an important solution to forest insect problems such as bud worms and gypsy moths in forests of Canada and the eastern United States. In 1960, both countries began field trials with commercially available preparations of Bacillus thuringiensis.Some preliminary results are encouraging.For example, at Wormont, the end results for bacterial control were as good as those obtained with DDT.Now, the main technical problem is to develop a solution that will stick the spores of the bacteria to the needles of evergreen trees.For crops there is no such problem—even powders can be used; especially in California, bacterial insecticides have been tried on a variety of vegetables. Meanwhile, another, perhaps less visible line of work has been done around viruses.All over the fields of young alfalfa in California, hills and plains are being sprayed with a substance that is as lethal at killing alfalfa caterpillars as any insecticide. The virus solution in the body, these caterpillars had died due to infection with this extremely virulent disease.Just 5 diseased caterpillars will provide enough virus to treat one acre of alfalfa.In some Canadian forests, a virus effective against the pine sawfly has achieved remarkable results in insect control and is now being used in place of insecticides. Scientists in Czechoslovakia are experimenting with protozoa against fabric worms and other infestations; in the United States, a parasitic protozoa has been found to reduce the egg-laying capacity of grain borers. There are some theories that microbial pesticides could wreak dangerous bacterial warfare on other forms of life.But this is not the case.Compared with chemical drugs, insect pathogens are harmless to all organisms except the objects they are intended to act on.Dr. Edward Stenhouse, a distinguished authority on entomopathology, emphasized: "There has never been a proven disease that actually causes infectious diseases in vertebrates, either in the laboratory or in the wild. entomopathogens.” Entomopathogens are so specific that they are infective to only a small group of insects, sometimes only one species.As Dr. Stenhaus points out, outbreaks of insect diseases in nature are always confined to insects, affecting neither the host plant nor the animals that eat them. Insects have many natural enemies - not only many types of microbes, but other insects as well.The first biological means of controlling insects, whereby an insect can be controlled by stimulating the development of its enemies, is generally due to Erasmus Darwin in 1800.Perhaps because the treatment of one insect against another is generally the first tried method of biological control, it may be widely and erroneously considered the only alternative to chemicals. In the United States, biological control as a routine method began in 1888, when Albert Koyebel (the first member of a now growing trailblazing contingent of entomologists) went to Australia in search of downy leaf pillows A natural enemy of the scale insect that threatens to destroy California's citrus industry.As we have seen in Chapter 15, this task has been spectacularly successful, and throughout the twentieth century the world has searched for natural enemies to use in controlling the insects that have made their way to our shores.In total, about 100 important predatory and parasitic insect species have been identified.In addition to the Victoria beetle brought in by Koyebel, other insect imports were also successful.A wasp imported from Japan has taken full control of an insect ravaging eastern apple orchards.Some of the natural enemies of the spotted alfalfa aphid were accidentally imported from the Middle East and are credited with saving the California alfalfa industry.Predators and parasites of the gypsy moth are as well controlled as the black wasp is to the Japanese beetle.Biological control of scale insects and wax worms is expected to save California several million dollars a year—indeed, Dr. A $4 million investment in biological control work has yielded a return of $100 million. Examples of successful biological control of severe infestations through the introduction of natural enemies of the insects have occurred in approximately 40 countries throughout the world.This method of control has clear advantages over chemical methods: it's less expensive, it's permanent, and it leaves no residue.But biological control has been lacking in support.California is virtually alone among states in establishing formal biological control programs, and many states do not even have a single entomologist dedicated to biological control research.Perhaps, to gain support, the use of insect enemies for biological control has always lacked a scientific rigor—the effects of prey insect species on biological control have hardly been rigorously studied, and Predator dispersal has not been done with the precision that could mean the difference between success and failure. Both predator and prey do not exist alone, they exist only as part of a vast web of life, and all this needs to be considered.Perhaps the greatest opportunity for the use of established biological control methods is found in forests.The farmland of modern agriculture is highly artificial, which is quite different from the imagined natural state.Forests, though, are a different world, closer to natural environments.There, with the least human intervention and disturbance, nature can develop as it is, setting up the wonderful and intricate system of checks and balances that protects the forest from undue insect infestation. In the United States, our foresters seem to have considered biological control primarily through the introduction of predatory and parasitic insects.The Canadians have taken a wider view, while some Europeans have gone further and developed "forest hygiene" to an astonishing degree.鸟、蚂蚁、森林蜘蛛和土壤细菌都同树木一样是森林的一部分，欧洲育林人在这种观点下，他们栽种新森林时，务必也引人这些保护性的因素。第一步是先把鸟招来。在加强森林管理的现时代中，老的空心树不存在了，啄木鸟和其他在树上营巢的鸟从而失去了它们的住处。这一缺陷将用巢箱来弥补，它吸引鸟儿们返回森林。其他还有专门为猫头鹰、蝙蝠设计的巢箱，这些巢箱使鸟儿得以度过黑夜，而在白昼这些小鸟儿们就能进行捕虫的工作。 不过，这仅仅只是开始。在欧洲森林中最吸引人的一些控制工作是利用一种森林红蚁作为一个进攻性的捕食昆虫，——这个种类很可惜没有在北美出现。约在二十五年以前，乌兹柏格大学的卡尔·高兹华特教授发展了一种培养这种红蚁的方法，并建立了红蚁群体。在他的指导下，一万多个红蚁群体已被放置在德意志联邦共和国的九十个试验地区中。高兹华特教授的方法已被意大利和其他国家所采用，他们建立了蚂蚁农场，以供给林区散布蚁群用。例如，在阿平宁山区已建起几面个鸟窝来保护再生林区。德国穆林的林业官汉斯.鲁波绍芬博士说：“在你的森林中，你可以看到在有鸟类保护、蚂蚁保护、还有一些蝙蝠和猫头鹰共同体的那些地方，生物学的平衡已被显著地改善了。”他相信，单一地引进一种捕食昆虫或寄生昆虫其作用效果要小于引入树林的一整套“天然伙伴”。 穆林的森林中新的蚁群被用铁丝网保护起来以免受啄木鸟的打劫。用这种办法，啄木鸟（它在试验地区10年中已增加了400%)就不再能大量危害那些蚁群，啄木鸟只好通过从树木上啄食有害的毛虫而偿还它们曾造成的损失。照料这些蚁群(同样还有鸟巢箱)的大量工作是由当地学校的10一14岁孩子组成的少年组织来承担的。花费是极低廉的；而好处则是永久性地保护了这些森林。 在鲁波绍芬博士工作中另一个极为有趣的方面是他对蜘蛛的利用，在这一方面他是一个开路先锋。虽然现在已有大量的关于蜘蛛分类学和自然史方面的文献，但它们都是片断的、支离破碎的，并且完全不涉及它们作为生物学控制因素所具有的价值。在已知的22，000种蜘蛛中，760种是在德国土生土长的(约2000种在美国土生土长)。有二十九族蜘蛛居住在德国森林中。 对育林人来说，关于蜘蛛的最重要的事实是它们织造的网的种类，造车轮状网的蜘蛛是最重要的，因为它们中间一些所织的网有着如此细密的网孔，以致能捕捉任何飞虫。一个十字蛛的大网(直径达16英寸)在其网丝上约有120，000个粘性网结。一个蜘蛛在它生存的18个月中可平均消灭2000个昆虫。一个在生物学上健全的森林每平方米土地上应有50到150个蜘蛛。在那些蜘蛛数量较少的地方，可以通过收集和散布装有蜘蛛卵的袋状子囊来弥补。鲁波绍芬博士说：“三个蜂蛛(美国也有这种蜘蛛)子囊可产生出一千个蜘蛛，它们共能捕捉200，000个飞虫。”他说，在春天出现的小巧、纤细的幼轮网蛛特别重要，“当它们同时吐丝时，这些丝就在树木的枝头上形成了一个网盖，这个网盖保护枝头的嫩芽不受飞虫危害。”当这些蜘蛛蜕皮和长大时，这个网也变大了。 加拿大生物学家们也曾采取了十分相似的研究路线，虽然两地实际情况有些差异，如北美的森林不是人工种植的，而在更大程度上是自然状态的；另外，在对森林保护方面能起作用的昆虫种类土也多少有些不同。在加拿大，人们比较重视小型哺乳动物，它们在控制某些昆虫方面具有惊人的能力，尤其对那些生活在森林底部松软土壤中的昆虫。在这些昆虫中有一种叫做锯齿蝇，人们这样称呼它，是由于这种雌蝇长着一个锯齿状的产卵器，它用这个产卵器剖开常绿树的针叶，并把它的卵产下去。幼虫孵出后就落到地面上，并在落叶松沼泽的泥炭层中或在针枞树、松树下面的枯枝败叶中成茧。在森林地面以下的土地中充满了由小型哺乳动物开掘的隧道和通路，形成了一个蜂巢状的世界，这些小动物中有白脚鼠、鼷鼠和各种地鼠。在这些小小的打洞者中，贪吃的地鼠能发现和吃掉大量的锯齿蝇蛹。它们吃蛹时，把一只前脚放在茧上，先咬破一个头，它们显示出一种能识别茧是空的还是实的的特别本领。这些地鼠的贪婪胃口是惊人的。一个鼷鼠一天只能吃掉200个蛹，而一个只靠吃这种蛹为生的地鼠则每天能吃掉800个以上。从室内实验结果看，这样能够消灭75一98%的锯齿蝇蛹。 下述情况是不足为怪的：纽芬兰岛当地没有地鼠，所以遭受到锯齿蝇的危害；他们热切盼望能得到一些这样能起作用的小型哺乳动物，于是在1958年他们引进了一种假面地鼠(这是一种最有效的锯齿蝇捕食者)进行试验。加拿大官方于1962年宣布说这一试验已经成功。这种地鼠正在当地繁殖起来，并已遍及该岛；在离释放点l0英里之远的地方都已发现了一些带有标记的地鼠。 育林人想力求永久保存并加强森林中的天然关系，现在已有一整套装备可供他使用。在森林中，用化学药物来控制害虫的方法充其量也只能算是个权宜之计，它并不能真正解决问题，它们甚至会杀死森林小溪中的鱼，给昆虫带来灾难，破坏天然控制作用，并且把我们费九牛二虎之力引进的那些自然控制因素毁灭掉。鲁波绍芬博士说：由于使用了这种粗暴手段，“森林中生命的协同互济关系就变得完全失调了，而且寄生虫灾害反复出现的间隔时间也愈来愈短……因而，我们不得不结束这些违背自然规律的粗暴作法，这种粗暴作法现已被强加到留给我们的、至关重要的、几乎是最后的自然生存空间之中”。 我们必须与其他生物共同分享我们的地球，为了解决这个问题，我们发明了许多新的、富于想象力和创造性的方法；随着这一形势的发展，一个要反复提及的话题是：我们是在与生命——活的群体、它们经受的所有压力和反压力、它们的兴盛与衰败——打交道。只有认真地对待生命的这种力量，并小心翼翼地设法将这种力量引导到对人类有益的轨道上来，我们才能希望在昆虫群落和我们本身之间形成一种合理的协调。 当前使用毒剂这一流行作法的失败使人们考虑到了一些最基本的问题。就象远古穴居人所使用的棍棒一样，化学药物的烟幕弹作为一种低级的武器已被掷出来杀害生命组织了——这种生命组织一方面看来是纤弱和易毁坏的，但另一方面它又具有惊人的坚韧性和恢复能力，另外它还具有一种以预料不到的方式进行反抗的秉性。生命的这些异常能力一直被使用化学药物的人们所轻视，他们面对着被他们瞎胡摆弄的这种巨大生命力量，却不曾把那种“高度理智的方针”和人道精神纳入到他们的任务中一去。 “控制自然”这个词是一个妄自尊大的想象产物，是当生物学和哲学还处于低级幼稚阶段时的产物，当时人们设想中的“控制自然”就是要大自然为人们的方便有利而存在。应用昆虫学上的这些概念和作法在很大程度上应归咎于科学上的蒙昧。这样一门如此原始的科学却己经被用最现代化、最可怕的化学武器武装起来了；这些武器在被用来对付昆虫之余，已转过来威胁着我们整个的大地了，这真是我们的巨大不幸。