From Farm Spies, How the Boys Investigated Field Crop Insects by A. F. Conradi, and W. A. Thomas; New York: The Macmillan Company, 1916; pp. 126-145.
THE COTTON-ROOT LOUSE
IT was in the spring of the year. The sun was sinking on the western horizon, and trees and bushes cast long shadows over the landscape. Every living thing was hopeful, and the farmers of the Gardner section were more hopeful than usual because the spring weather had been fine; they had all prepared their fields well and had finished up their spring plantings. The cotton was just coming up and with the eye, when helped a little by the imagination, once could trace the rows across the fields. Every one of the farmers in that section knew that a cotton-crop well planted in a thoroughly prepared seed-bed was half the battle. Even Si Fletcher, who rarely agreed with anything, said that this was correct, provided good seed was planted.
Joe Gardner was the youngest, most active, and most progressive farmer of the neighborhood, and as he had planted earliest of the other farmers his cotton was the tallest in the community. But Joe stood by the old bars at the edge of the cotton-field this evening and was very angry. Joe’s neighbors told him that he was foolish to be so angry about 127 something that he could not have prevented and to worry about things that he could not change. The truth is that they had noticed nothing wrong with their cotton except that they had very broken stands; they did not think much about it because they said that it had been that way every year as long as they could remember, and that it was natural. When Joe would not agree to this some of the older men said it was because he was so young. “Wait till he is a little older and he will know better,” one old neighbor said. His close friends, however, did not talk that way, but shook their heads gravely and said, “Joe does not often make a serious mistake.”
Will Gray was, no doubt, the most successful farmer next to Joe, and even he had not been able to see why Joe should be so discouraged.
Joe explained, “I took great pains and did everything I thought ought to be done in preparing my land for this planting and the cotton came up beautifully, but now the stand is broken everywhere. You can find a number of places in some rows where nearly ever plant is dead or sickly over a distance of a hundred feet.”
“You are grumbling over spilled milk, Joe,” said Will.
Just then Bill Green, who lived near the old bridge on a knoll on the south bank of Clear Creek, came along the road and heard the conversation. Bill 128 was born and reared where he lived and, being over seventy years old, felt that he knew everything that could be known about the country around there. He said to Joe, “I hev’ seen it afore and it come all right ag’in.”
Joe replied, “I had just a little of it last season, but what there was of it did not come all right again. The little cotton died and stayed dead. This year much of the cotton looks sickly just like that last year, and I am satisfied that it is going to die.”
Bill did not like Joe’s reply, and with an air of wisdom told Joe that it was the moon. “When the moon changes the cotton will grow, and you will make your crop all right,” he said.
Mr. Gardner hesitated, not that Mr. Green’s answer satisfied him, but he was big enough to know that the ways of nature are often beyond understanding and that even the wisest and oldest men are often unable to foresee what the results may be.
Sam Drake came along the road, stopped, and joined in the discussion. After the situation had been explained to him he looked at the cotton carefully with, what he proudly believed, knowing eyes. After wrinkling his forehead for a while, he turned to Joe and said: “You made a mistake; I done knew hit and said hit when I come down the road a couple 129 weeks ago and seen you a-plantin’. I had all my land ready to plant, but I didn’t because the signs weren’t right. You planted by the dark of the moon and you shouldn’t have done it. That is what I say.”
Joe answered that he did not believe that to be the cause of the cotton’s dying.
“Hold on here, Joe,” Bill interrupted, very much vexed that a youngster like Joe should reject the decision of his old neighbors; “you are going altogether too fast; you are exceedin’ the speed-limit; me and Sam here are old farmers and remember the day you was born. We have lived here all our lives, and if we don’t know this country then I would like to know who does. Me and Sam have grown as much as forty acres of cotton a year, and we always had enough cotton to sell that we could buy all the corn for meal and we made our own bacon. You are but a young feller and have a heap to learn yet.”
Joe replied, I want more than a little corn bread and bacon if I stay on the farm. Then I don’t care how old you men are or how long you have lived here, I do not believe that the moon has anything whatever to do with this cotton’s dying. There is some good reason for it, and I am going to find out if I can.”
When Bill and Sam drove on they did not look as 130 if they were laughing, and Joe, paying no further attention to them, started for the home of George Elliot, the farm demonstration agent, and told him the trouble. Joe knew that Sam and Bill did not think very highly of the demonstration agent, “Because,” they said, “that fellow is too young to tell us old farmers anything. We knew him when he was a little shaver going to the old field school down by the crossroads. He has lived here all the time except for a short time, when he was to what people call college. No, siree, Georgie has to wait a while before he can teach us anything about farming.”
Joe knew that the demonstration agent did not presume to know everything, but he said to himself, “He always has a way of finding out when he does not know.”
The farm demonstrator went to the fields and examined the cotton and said, “I do not know what the trouble is, Joe, but I will send some of those plants to the State agent at the agricultural college, who will have one of the experts examine it.”
Some of the older men who heard what the demonstrator said looked at each other with a wise smile and remarked, “Didn’t I tell you; that demonstrator does not know. He planted by the dark of the moon; that is the trouble, ahem!”
Mr. Elliott wrote his letter and sent the plants, and a few days later he received a report that the plants 131 had been examined and that the experts found them attacked by root-aphids and that one of the experts would be at the farm of Joe Gardner and would advise any one interested what to do.
The man who came there was an entomologist; that is, he was a man who made a study of insects. Early on the Wednesday morning many farmers, old and young, came to hear what the entomologist had to say. When they first saw him, many of the older men were very much disappointed because he appeared so young. The young entomologist carefully examined the plants. When he could find nothing on the leaves and stalks he took a trowel and drove it into the ground and lifted the plant out, roots and all, together with the soil about the roots. After he had scratched the earth away from the roots with great care, they saw many little bluish, soft-bodied, sucking insects. “What are they?” several of them examined with surprise. “We never saw such bugs on the roots of cotton,” others said.”
“That is, no doubt, correct,” the entomologist answered.
Another farmer exclaimed, “My cotton is dying the same way, and I have examined the roots of many of the plants, but I don’t find any of these bugs, so I know that this is not the trouble with my cotton.”
132“Did you dig up your plants as I did this one?” the entomologist asked.
“Why, no,” answered the man, “I did not take time to dig them up; I just pulled them up, examined them, and had done with it.”
The entomologist replied. “That is very likely the reason that you did not discover these bugs when you examined the plants. These insects are cotton root-aphids, or what some people call root-lice. They occur mainly on the small feeding roots as you will notice when you look at this plant which I have dug up. You see they have their beaks fastened in the tissues, and when you pull up a cotton plant the little feeding roots are torn off, leaving the aphids in the ground. When a few occur on the main stem they will be pulled off when the plant is drawn through the soil to the surface. If, therefore, you pull a plant instead of digging it up, you many not see the aphids, then you come to the conclusion that the roots are clean. In the way I lifted the plant from the soil, the roots are retained by the plant and will bring the aphids to view if there are any.”
Fig. 54. — “These insects are cotton root-aphids.”
At this time Jake Wheeler relieved his mouth of 133 a load of tobacco juice which he had let unconsciously accumulate while listening to the entomologist, and approaching Bill Green, said in an undertone which was almost a whisper, “Say, Bill, I believe that young fellow knows what he is talking about.”
Bill, who had been watching and listening with interest to what the entomologist said and did, removed his corn-cob pipe from his mouth long enough to reply, “He sure does, Jake. In them good clothes, and appearin; young-like, he looked like one of them city fellers, but he sure talks so we can understand him. He sure does.”
Joe, who had become greatly interested in what the young entomologist had said, asked, “How in the world did all those aphids get there so early in the season? They certainly could not have been there during the winter because there was nothing green on the fields.”
Fig. 55. — “How in the world did all these aphids get there so early in the season.”
“The habits of these aphids are quite well understood,” the entomologist started to explain; 134 “entomologist have worked on what we believe to be the same kind of aphid for many years. Some get to the cotton by flying, as a certain number of them get wings. Most of them are carried by the little ants that you see so abundantly here on the ground.”
“Carry them there! carry nothing!” exclaimed old Jack Terrell.
“Don’t carry them there? What makes you say that?” the entomologist asked.
“They eat them, and that is just what these ants are good for,” Jack answered. “If it wasn’t for those ants these little bugs would not let us grow a single stalk of cotton.”
“Have you ever seen an ant actually eat an aphid, or, have you at any time seen an ant eat an aphid anywhere?” asked the entomologist.
“No-o-o,” Jack replied hesitatingly, as though by reflecting he must recall having seen it; “but,’ he continued, “I have seen the ants have these lice in their jaws and that is enough, is it not? The ants eat the lice or aphids as you call them, and that is what I say.”
“No doubt you have seen them between the jaws of the ants, but if you had watched them long enough your conclusion would have been an entirely different one. Had you watched long enough you would have found the ants, which you believed 135 were eating the aphids, in the act of carrying them to some desirable plant food. They were not eating the aphids, but they were merely transferring them from a poor food-plant or from their burrows to another or better food-plant, just as the mother cat carries her kittens from one place to another.”
Jack stood and stared at the entomologist, with his mouth wide open. Then the entire group of farmers burst into a laugh which angered him.
“Piffle,” he exclaimed. “Nonsense! I have been farming all my life and you can’t make me believe such a fool thing as that.” Thereupon he turned on his heels and went straight home. Just what he said when he arrived home no one has been able to find out exactly.
The entomologist looked serious, and did not know what to think of such a performance, when Joe turned to him and said, “Don’t mind him, because when he has a notion you nor anybody else could get him away from it. Go on and tell us more about the ants and aphids. What object has the ant in being so plagued hospitable to the aphids?”
The entomologist continued: “This question of ants attending aphids is an old one and is quite well understood, not only in regard to these particular ants but with others as well. These are known as the corn or cotton-field ants because they are so common and so well known to everybody. They 136 are so much interested because they enjoy eating the sweet liquid or honey-dew made by the aphids. The ant does not require this honey-dew because it has been shown that she can live without it, but the ant loves it just as a boy loves ice-cream or the mosquito loves blood. The ant is willing to put itself to a great deal of trouble attending the aphids in order to get the honey-dew.”
Joe asked, “You say that the aphids are carried there by ants, and when the plant upon which they feed fails they carry the aphids to other and healthier plants, all for the honey-dew?”
“That is correct,” he replied.
“Now, then,” Joe continued, “this goes on throughout the summer and fall when it is warm and there are growing plants on the field, but what happens when winter comes, when the plants all die and the ground becomes chilled?”
“It does appear as if this might be a serious matter, especially to those who have not studied the ways of ants,” the entomologist replied, “but the ants have more foresight than most people are willing to give them credit for. The ants realize that the aphids are the machinery for making honey-dew, and for this reason must be protected. When the food-plants die in the fall the ants invite the aphids to their warm burrows of their own underground homes. The aphids never seem to hesitate in accepting this 137 invitation and the ants seize them in their strong jaws and carry them to their homes. This is what Jack Terrell saw, and it led him to the conclusion that the ants ate the aphids. In the underground homes of the ants the aphids are at ease. Although ants are somewhat eccentric about who shall, and who shall not, be allowed the liberties and protection of their burrows, yet the aphids are free to visit any chamber. Not only do they enjoy free passes to go where they wish, but the ants even show them every courtesy, and no occupant of the ant-home is allowed to molest them.”
“How do the aphids get their food during the winter, for they surely have no means of support in the ant-homes?” inquired Will Gray.
The entomologist answered, “Nature has so provided that during this period of indolence, which lasts from two to three weeks, the aphids can fast. In the meantime the ants are very active, scouting in the field in every direction in search of desirable food-plants, principally life-everlasting, ants as soon as these are located small channels or galleries are constructed about the tender roots; the burrows around the roots of life-everlasting are then connected with the channels of the ant homes by underground passages, and they transfer the aphids to these tender roots undisturbed by frosty air and biting winds. The aphids immediately insert their 138 beaks into the roots to satisfy their hunger, at the same time making delicious honey-dew which they yield to the ants willingly in pay for coming between them and destruction at the approach of winter. In most cases this arrangement provides sufficient food until the spring plants appear again.”
Joe had become excited. “In the spring the ants carry the aphids to the young plants as they come up, do they?” he asked.
“Well, yes, but there is a faster way,” the entomologist explained. “Nature has so endowed the aphids that in the spring when the winter food-plants fail in their supply of sap, the little wingless creatures produce a large number of winged individuals, which, driven by impulse, leave the homes of their protectors and fly through the air in every direction in search of the sweet juice of the young cotton plants.”
( After Forbes. )
Fig. 56. — “The little wingless creatures.”
“How in the world do the ants find the aphids again after they let them fly away?” Sam Drake asked.
( After Forbes. )
Fig. 57. — “And fly through the air in every direction.”
“I was just going to tell you about that,” the entomologist replied. “It seems that even before 139 the aphids acquire wings the ants foresee what is coming, and are very active in the cotton-fields. By the time the aphids reach the fields the ants are there to receive them. The little rogues have already finished the tunnels, and, running in every direction, they discover the aphids and carry them to the roots of the young cotton through the tunnels made for that purpose. Here the aphids find plenty of food and are soon surrounded by little family groups.”
“Gentlemen,” said Joe Gardiner, “this is a treat. I never knew that these little bugs were so wise. Could you tell us what we might do to prevent them from killing our young cotton? There are plenty of other plants here to which they are welcome. They can have any whole wood-lot pasture over there and I would watch them work whenever I had time. They are cute and hard working little fellows and they are welcome to live on my farm, but I cannot let them have my cotton merely to satisfy their thirsty little throats for honey-dew.”
“Put something in the fertilizer,” exclaimed Will Gray. “Can’t you do that?”
140“That is the same old question asked over and over again until it is almost worn out. We have tried everything we could think of, hoping that we might be able to kill them in the soil or drive them away from the plants. Among the many things experimented with none has so far proven effective. We have made up our minds that the only remedy so far known is hard sensible farming. That, we know, does control them.”
“The first step is to keep the aphids off the field for at least one year, or, in other words, drive them away from the field.”
“How can you do that?” several exclaimed.
The entomologist continued: “we have studied the food-plants and we know quite well on which plants the aphids can live and also those on which they cannot live. For this reason we keep their food-plants off the field which is to be planted in cotton; this forces them to leave and allows the cotton to get a good start before enough aphids can be brought back to harm the plants. It will never do to let your land, on which you wish to plant cotton, lie idle during the winter, because that gives the wild food-plants a chance to grow on such land, and I have already explained to you how well the ants know how to make use of them.”
“What are some of those wild food-plants you are talking about?” several farmers asked.
141“There are a number, but the plants known as life-everlasting are the most important. There is one,” and the entomologist pointed to a plant on the ground.
Fig. 58. — “Life-everlasting are the most important.”
“What are some of the plants on which they cannot live?” they asked.
“Among our farm crops are oats, rye, barley, wheat, vetch, clover, and peas, and these are all plants which you know well and which you are growing on your farms,” the entomologist explained. “when you plant a heavy cover-crop of one of the 142 plants on which the aphids cannot feed, the weeds have little chance to grow during the winter.
Fig. 59. — “The weeds have little chance to grow during the winter.”
They are cleaning crops because they clean the fields of weeds and aphids. Many farmers call them cover-crops because they will take up the plant-food and hold it so it cannot waste during the winter; they also hold the soil-moisture and keep the soil from washing during heavy rains. You can see how important it is to use these cover-crops even when you have no aphids. Let us take, for example, this farm on which Mr. Gardner grows cotton, corn, and oats as the main crops. Oats planted in the fall keep down the weeds during the winter, and since 143 the aphids do not feed on oats, the ants would not care to keep them there just to starve. If the ants figure on getting into the field after the oats are harvested, they are badly mistaken, because the oats are followed by cowpeas, which is not a food-plant for the aphids. To make matters still worse for the ants and aphids, you follow the cowpeas with oats, rye, vetch, or clover for winter cover; as none of these is a food-plant there will be few aphids on that field by spring. Then is the time to plant the field in cotton.”
“Why not plant that field in corn?” one farmer asked.
“Because,” answered the entomologist, “there is no crop on the farm that suffers so much from these aphids as cotton, and for that reason you should give cotton the first chance after the field is clean.”
“In regard to cultivation,” the entomologist continued, “as soon as the cotton is large enough, begin and give it frequent shallow cultivation until the plants have a good start. This cultivation nettles the ants very much because they do not go by sight as you or I do, but they seem to go from one place to another by following trails made before. Just think, Mr. Gardner, if you were an ant and wished to go home you would have to follow some trail you made when you came to the field before, instead of looking and seeing your house and then walking 144 to it. Should anything have destroyed the trail you would lose your way and be as much nettled as the ant. There! watch that ant crossing from one row to the other;” he said, pointing to an ant crawling on the soil; “she does not go in a straight line and doesn’t it look as if she is following an old trail? Let us see if there is any sense in my thinking so.” The entomologist then rubbed his fingers over the ground in front of the ant, and sure enough, when she came to his finger-mark she stopped and was vexed.
“Now,” continued the entomologist, “think of a harrow or some other shallow tool going through this row, how it must confuse the ants and how impossible it must then be for them to care for the aphids. I have often thought how the ants must smile when a farmer does not cultivate as he should. To control this aphid is a case of humbugging an ant. The best way is to rotate crops intelligently, and to give thorough shallow cultivation when the plants are young.”
It was now late in the afternoon and the people started for their homes.
Since this meeting in Joe Gardner’s cotton-field many of the farmers of that section have greatly improved their lands by intelligently rotating the crops and giving cotton rapid shallow cultivation when it is young. George Elliot, the county demonstration 145 agent, is still there, and he says that where the root-aphids used to kill the cotton nearly every spring, they do no damage now. Whenever come one says that the agent is too young, Joe and the other good farmers always reply, “He is doing more good helping the farmers of this county than anybody else. It was he who got the entomologist to come and tell us about the root-aphid, and we now know how to humbug this pest.”
Although this happened many years ago the old bars are still there, and whenever Joe passes them going or coming from the field he recalls with a smile that evening when he stood there so angry because he did not know what was killing his cotton.