Krogstad, Blanchard O.

English

University of Minnesota, Morris (UMM): Digital Well

Journal of the Minnesota Academy of Science Volume 19 Number 1 Article 10 4-1951 The Biology of the Goldenrod Gall-Fly, Eurosta solidaginis (Fitch) Blanchard O. Krogstad University of Minnesota Follow this and additional works at: https://digitalcommons.morris.umn.edu/jmas  Part of the Entomology Commons Recommended Citation Krogstad, B. O. (1951). The Biology of the Goldenrod Gall-Fly, Eurosta solidaginis (Fitch). Journal of the Minnesota Academy of Science, Vol. 19 No.1, 23-24. Retrieved from https://digitalcommons.morris.umn.edu/jmas/vol19/iss1/10 This Article is brought to you for free and open access by the Journals at University of Minnesota Morris Digital Well. It has been accepted for inclusion in Journal of the Minnesota Academy of Science by an authorized editor of University of Minnesota Morris Digital Well. For more information, please contact skulann@morris.umn.edu. PROCEEDINGS, VOLUME NINETEEN, 1951 THE BIOLOGY OF THE GOLDENROD GALL-FLY, EUROSTA SOLIDAGINIS (FITCH) BLANCHARD 0. KROGSTAD University oj Minnesota Eurosta solidaginis is the most conspicuous member of an insect community which lives in the stem of the goldenrod, Solidago spp. This fly is most conspicuous because its larva produces a round gall which is readily seen along roadsides, especially during the fall and winter seasons. It was found that the gall-fly is distributed throughout most of the United States and Canada, and that in Minnesota the galls oc-cur on at least three species of goldenrods .. The adult fly emerges from its puparium during the latter half of May to the first part of June, depending on the locality and the season. It was found, contrary to previous beliefs, that the pre-oviposition period is very short ( only two days) and that the peak of oviposition is reached on the fourth day. Previous workers have stated that eggs are deposited on the outside of the Solidago stem. In this study it was found that the female punctures the terminal shoot of the goldenrod plant and deposits eggs in the growing tip. Only one egg is deposited in each puncture. The period of adult existence is only 8 to 10 days. Their feeding habits throughout this short period is not known to date. The eggs normally require from 9 to 11 days for incubation with the seasonal temperature variations undoubtedly affecting this peri-od to some extent. After eclosion the larva bores into the center of the growing tip and begins to feed. It is the excrement or the sali-vary juices of the larva which are instrumental in causing gall growth. The gall grows rapidly so that it is full grown by the end of one month. The larva moults two times during its growth; once during the first part of July and the second time during the first part of August. In the fall the larva bores a tunnel from its central cavity to the outer epidermis. The tunnel cannot be detected visually since the waxy epidermis covering the stem is not disturbed by the larva. This tunnelling occurs during the months of September and Octo-ber, the exact time depending on the conditions of moisture present in the plant on which the gall is located. It seems that tunnelling by the larva is made in response to the relative humidity to which the larva is exposed and is affected only secondarily by a decrease in temperature. After boring the tunnel the larva returns to the central cavity and remains over winter in that condition. Pupation occurs during the month of April and generally the adults emerge about one month later. 24 TuE lVIINNESOTA AcADEMY OF ScIENcE Natural enemies such as insect parasites and birds take a heavy toll of larvae throughout the year. Drought was also found to be rtn important factor in limiting the population of the insect. These !"actors will not be discussed further in this paper. This species can be of considerable value to a teacher, whether it be at the elementary, high school or college level. Its constant avail-ability throughout the fall, winter and spring seasons in most parts of the United States, in addition to the fact that the larvae may be induced to pupate and the adults emerge at any desired time make it an especially convenient source of laboratory demonstration ma-terial. This species of insect can be used to demonstrate a number of biological principles: complete metamorphosis, gall formation, parasitism by other insects, commensalism, and superparasitism . .., .., .., SOME CHARACTERISTICS OF A PROTEINASE ASSOCIATED WITH HONEYBEE LARVAE KILLED BY AMERICAN FOULBROOD DISEASE T. A. GOCHNAUER ' Research Associate, Divis-ion of Entomology and Economic Zoology University of Minnesota ABSTRACT Preliminary studies were conducted on the activities of a pro-teolytic enzyme associated with the spores of the bacterial agent that causes American foulbrood diseases of honeybee larvae, name-ly, Bacillus larvae. The enzyme is found in the remains of the larvae infected by the micro-organism, and thus serves as a visible indi-cator of infection in field tests. These tests use the ability of the enzyme to curdle and peptonize milk suspensions as an end point. However, some workers had found the test difficult or impossible to use, and in some cases the results were contradicted by labora-tory examination of the samples for viable spores. Therefore this work was started in order to find means of increasing the sensi-tivity of the test, to define some of the limits of the reaction condi-tions, and to test the effect of interfering substances. · The peptonizing activity was apparent over a range of pH 6.0-7 .0 in M/10 phosphate buffer, with an optimum of 6.6. The curdling activity was similar to that of rennin, displaying increased activity in the acid range. The peptonizing activity was increased by the addition of chlor-ides, up to 0.2 per cent added NaCl or KCl, and was proportional to the temperature up to 45 degrees Centigrade. Of these three fac-tors, the chloride effect is most easily controlled by the field test 

The Biology of the Goldenrod Gall-Fly, Eurosta solidaginis (Fitch)

https://digitalcommons.morris.umn.edu/cgi/viewcontent.cgi?article=1903&context=jmas

The Biology of the Goldenrod Gall-Fly, Eurosta solidaginis (Fitch)

Abstract

Similar works

Full text

Available Versions

University of Minnesota, Morris (UMM): Digital Well