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THE PUPAL PERIOD,

An individual that pupated July 29 at 4 p. m. transformed to adult at about the same hour August 6, just eight days later. A second that transformed to pupa at the same time did not issue till 1 p. m. the following day. A third example found to have pupated early on the morning of July 28 did not issue as a moth till 3.15 p. m. of August 7. These three rearings alone show that there may be considerable individual variation in even so small a matter. The two pupa were kept side by side and under precisely the same conditions.

The temperature was exceedingly hot, the thermometer ranging from 850 to 920 F.

Other experiments at different temperatures gave from nine to twenty seven days as the period of the pupa state, as follows:

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The duration of the larval period is more difficult of observation than is that of the egg or the pupa. Time, labor, and patience may be saved by simply calculating it by subtracting the egg and pupal periods from the entire cycle periods.

This would give us, by estimate from experiments Nos. Hand 5 (thirtyeight and thirty-nine days), a larval period of twenty four or twentyfive days as a known minimum.

Mr. Johnson's article on the flour moth is the most complete work yet published on any species of insect affecting stored grain. Bis results are beyond question, and although he has refrained from untavorable comment, in self-defense I must pass criticisin.

Admitting a difference in atmospheric conditions between the Dis. trict of Columbia and central llinois, where Mr. Johnson's shortest period was obtained, it should not be more than a week, as affecting the entire life cycle of an insect. Again, the months of May and June, in which this period was obtained, can scarcely be considered midsummer. Finally, if it could have been foreseen that our hot spell of this year was to occur in August, and observations conducted accordingly, starting an experiment about three or four weeks later than was done, I tbink it will be conceded that this period would not have occupied more than the estimated five weeks.

PROTRACTED DEVELOPMENT.

From my experience with this and other species I have become convinced that cases of protracted development are not only not rare to a limited number of individuals of a brood, but seem to be normal, and hence may be "part and parcel" of the “wise provisions of nature” for the continuance of a species.

A larva of Ephestia kuehniella that bad been placed in a small vial began spinning web May 9, but progressed very slowly, remaining motionless, always head downward, when examined daily for a week. Once or twice afterwards the larva was observed to have reversed its position, resting for several days at a time head upward. June 5 it was seen to have added a second coating of silk about double that first deposited. July 6 it bad resumed its old position of resting head downward. It was always motionless, but wriggled when touched. The work of observing this larva had become tiresome, as it had not undergone any change for at least two months. October 1 the moth was found to have issued. It was living and slightly worn, showing that it had bred out during the last of September. The weather having been unseasonably hot during what must have been the pupal period, the duration of this stage may be placed as nine days, from which the quiescent larval period of this individual may be deducted as over five months. Before transforming this larva had deserted the old web and spun a new cocoon. The moth was of full size and not shriveled.

E.rperiment in flour.-The eggs laid April 18 served for the determination of the egg period and for the late spring life cycle period in corn meal as just related. The newly hatched larvæ were divided into two portions, the second lot placed in wheat flour gave rather surprising results, for whereas the meal fed larvæ developed, as previously stated, in fifty-two days, not a moth issued from the flour until August 10, one hundred and fourteen days from the time of egg deposition. The flour was very fine and must have been exceedingly dry. The corn meal was fresh, yellow, of the best quality, and hygroscopic, which will explain the great difference in the periods of the larvæ feeding upon each.

An apparently, normal case.–From the same lot of eggs that had begun to be deposited by a single female April 18 and placed in corn meal, full-grown caterpillars to the number of 9 were observed at rest at the top of the jar June 2. At the same time a cocoon was observed in the meal, which gave out the first moth June 9. Many more motlis continued to issue from the meal, but were still maturing when the first moths from the larvae that had spun up at the top of the jar issued. These latter appeared July 9, or just one calendar month later than the first lot, which is the period of the protracted development in this second instance for four individuals.

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In Bulletin 4 (p. 28) of the Minnesota Agricultural Experiment Station Dr. Lugger figures Melanoplus bivittatus as clinging after death to the top of some plant where it died of a fungous disease. So far as I am aware, there are no records of grasshoppers dying in a similar manner of a bacterial disease previous to the announcements in the papers of the country of such a disease carrying off large numbers of grasshoppers in Colorado last summer. Although I can say very little in regard to the specific organism that causes the disease under consideration, it will doubtless be of some interest to the members of the association to learn of the work of the disease in Colorado so far as I have been able to determine it.

On June 20, 1895, I received from Mr. George R. Lee, editor of the Brighton Register, a letter and a package, the latter containing a few grasshoppers that had died clinging with all their legs to the tops of alfalfa stems. The letter stated that grasshoppers were dying in this peculiar manner in great numbers about Brighton, and that the farmers were greatly interested in the matter and wanted to know the cause. In reply it was stated that the grasshoppers were apparently dying of a bacterial disease, and not from the parasitic attacks of other insects. This letter was published in the Brighton Register and was taken up by the Associated Press and published all over the country. I recommended that all who had grasshoppers that were not dying of the disease should obtain dead and dying hoppers from Brighton and endeavor to inoculate those in their own localities. Farmers drove long distances, and those who were too far away to drive wrote letters sending money for diseased grasshoppers. In this way the diseased hoppers were taken into many parts of the State, as well as into sev. eral surrounding States. I sent diseased boppers to Dr. Lugger, of Minnesota, and Dr. Forbes, of Illinois, but I believe neither of these gentlemen succeeded in starting the disease in his locality.

It should be said to the credit of Judge N. H. Taylor, who lives upon bis ranch near Brighton, that he first discovered the disease, and that he took a lively interest in scattering it as widely as possible. It was from his place that the larger part of the dead hoppers were sent out to infect those of other localities.

August 14 I visited the ranch of Mr. H. T. Miller, living 4 miles southwest of Fort Collins, where the grasshoppers were dying of the disease. Mr. Miller said he procured about 100 hoppers from Brighton, July 26, a few of which were still alive when received.

He caught about 100 grasshoppers from his field and contined them with the diseased ones twenty-four hours and then allowed them to escape and put in another 100. This was repeated each day for seven days. On the

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eighth day a few hoppers were found dead clinging to the tops of grain and alfalfa, and on the eleventh day they were dying rapidly over an area nearly a half mile in extent in the direction of the running water in the irrigating ditches. At the time of my visit the hoppers seemed to be dying rather slowly. I estimated, after considerable counting, that there was an average of 4 or 5 dead boppers and three or four times that number of living ones to a square yard in Mr. Miller's fields where the disease was most prevalent. An interesting feature of the disease in Mr. Miller's fields was that for a considerable distance from the point of infection nearly all the hoppers were dying on the ground, only an occasional one being found clinging to the top of a plant, while from a quarter to a half mile from this point nearly all were dying on the tops of plants. It was noticed, also, that most of the dead hoppers · were along irrigating ditches or upon low, moist ground. They were also abundant about hay ricks, where they accumulated in great numbers when the alfalfa was being gathered. They could be seen clinging to protruding straws to the very tops of the ricks. The progress of the disease was watched quite carefully upon Mr. Miller's place through the remainder of the grasshopper season. The hoppers died slowly to the last, but continued abundant, though they must have been greatly reduced by the disease. Mr. Miller affirms that they were not half as abundant a few days after the disease began taking them as they were before it appeared. Longmont, Colo., was twice visited, where the writer was shown every courtesy, and was driven to many farms, where the disease was spreading, by Mr. J. B. Adams, a successful farmer and bee keeper, who had introduced the disease on his place. Mr. Adams had followed my advice in introducing the disease, which was to crush the dead and diseased hoppers in a liberal quantity of water and to sprinkle this upon the living hoppers and their food plants about the borders of his fields in the evening when they were accumulating upon the tops of the plants for the night. When I visited Mr. Adams's place August 30 the hoppers seemed to be dying rapidly about those fields where the infection was introduced. A great many were seen in a dying condition. Near the border of one field a square yard was marked off at random and 52 dead or dying hoppers counted upon it. In these fields no hoppers could be found dying or dead upon the tops of the plants. A mile distant dead hoppers clinging to the tops of plants were found common, but not nearly as abundant as in Mr. Adams's fields. About 5 or 6 miles distant from Mr. Adams's place we came into a locality where dead hoppers were abundant, especially along ditch banks, clinging to the tops of plants.

In this locality we could not find tiat the disease had been intro. duced artificially by anyone.

Brighton was also twice visited, where everyone seemed more than willing to offer such assistance as he could in the investigation of the work of the disease. Mr. George R. Lee accompanied me to Judge Taylor's ranch, and I was shown where the first dead hoppers were seen. It was upon low, wet ground bordering an alfalfa field. Judge Taylor said he had never seen the grasshoppers so numerous as they were in his fields when the disease appeared. At the time of my visit there were almost no hoppers to be seen on his place. The Judge said that his first cutting of alfalfa was literally black with hoppers of every size, from the very smallest to the fully grown. In a ride of 10 or 12 miles into the country about Brighton alfalfa fields were passed where the tops, as seen from the road, were distinctly blackened by the dead hoppers which were very often piled in clusters of two, three, or four together. In this locality the great majority of dead hoppers were clinging to the tops of plants. I found by inquiring that farmers who had not introduced the disease were about as likely to have it abun. dantly as any, but that does not seem strange, as so many did obtain it. Most farmers seemed to have noticed that it first appeared along ditches or on low ground.

Wheat Ridge, near Denver, was also visited, and Mr. David Brothers, a member of the State board of horticulture, showed me the work of the disease in his locality, where the hoppers were dying on the tops of plants in considerable numbers. He did not know that the disease had been artificially introduced in his neighborhood.

Obserrations and experiments with the disease at the college.-On account of miscarriage in the mails I did not obtain diseased hoppers in quantity for experiment early in the season. The first diseased hoppers were obtained August 14 from Mr. H. T. Miller and quantities were afterwards obtained from Brighton, Longmont, and Wheat Ridge. August 14 a quantity of diseased hoppers were crushed in water and sprinkled upon living hoppers and their food in the fields in the evening. On the 16th, two days later, a single dead hopper was found clinging to au alfalfa stem, and from that time on the hoppers died slowly, mostly on the ground. During August and September the weather was dry and I can not learn that the disease spread rapidly anywhere.

Investigations in the laboratory.-(I can not at this writing find the book in which all the notes upon laboratory investigations were taken and will have to speak of this work quite briefly and from memory.) In the breeding cages the hoppers died much more rapidly than in the field, but in every instance they died on the ground and not clinging to the plants. Grasshoppers dying of the disease live but a few hours after they show from their actions that they are diseased, and when freshly dead they are perfectly healthy in appearance. They soon turn dark in color, however, and all the soft parts of the body become a dark, semifluid mass. The membranes between the segments of the body are so completely disintegrated that the head, thorax, and abdo men usually separate. The abdomen will often be found, soon after death, hanging in a flaccid condition and will come in pieces with the

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