View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Illinois Digital Environment for Access to Learning... LIBRARY OF THE UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN no. Q>G - ^^ SURVEY The Literature of Arthropods Associated with Alfalfa 1. A BIBLIOGRAPHY OF THE SPOTTED ALFALFA APHID Therioaphis maculata (Buckton) (Homoptera: Aphidae) D. W. DAVIS, Utah State University M. P. NICHOLS E. J. ARMBRUST A Biological Notes No. 87 ILLINOIS NATURAL HISTORY SURVEY URBANA, ILLINOIS — FEBRUARY, 1974 STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION NATURAL HISTORY SURVEY DIVISION Xm&i : : This paper is a contribution of Principal Investigators of the Alfalfa Subproject supported by an International Biological Program (IBP) sponsored grant, NSF Grant No. GB-34718, "The Strategies, Principles, and Tactics of Pest Population and Regulation in Major Crop Eco- systems." Subproject Director: E. J. Armbrust Principal Investigators: Ilhnois: E. J. Armbrust and W. G. Ruesink Utah: D.W.Davis Nebraska D. G. Hanway and E. A. Dickason New York R. G. Helgesen Kentucky: B. C. Pass Virginia: R. L. Pienkowski California: V. M. Stern The authors are grateful for the assistance of Dr. Mervin Nielson, USDA, ARS, Tucson, Arizona, who loaned us his personal bibliography. The illustrations used in the cover design of this booklet were provided by Dr. G. F. Knowlton, Utah State University. Distribution of Spotted Alfalfa Aphid Thrri„a,il:,s marulala The Literature of Arthropods Associated with Alfalfa I. A BIBLIOGRAPHY OF THE SPOTTED ALFALFA APHID Therioaphis maculata (Buckton) (Homoptera: Aphidoe) D. W. Davis, M. P. Nichols, and E. J. Armbrust The alfalfa ecosystem is unique among field-crop Mexico, but it required only a couple of years for the systems in that it represents a relatively long-lasting, well- aphid to spread throughout the southwestern part of the established, perennial system that exists nationally over United States. Shortly thereafter it was widely distrib- a variety of climatic, geographical, and edaphic condi- uted through most of the country. It is still considered tions. Because of these many subsystems, the interactions essentially a warm-climate insect best adapted to the with other specific agroecosystems or natural systems are southern tier of states. It has the ability, however, to equally as varied. Alfalfa supports a wide variety of spread rapidly on wind currents, so by mid- or late insects. These include destructive insects, pollinating in- season, it often spreads well into the colder areas of the sects, species that inhabit the fields because of the lush Rocky Mountains and Midwest. habitat but have little effect on the crop, and many other The spotted alfalfa aphid is much smaller than the associated predators and parasites. Because of the peren- pea aphid and can be readily distinguished both by size nial growth habits of alfalfa, many pest and beneficial and color. It is yellowish with dark spots. It also pro- insect species of other crops ovei^winter or build up in duces much more honeydew and can usually be recog- alfalfa before migrating to neighboring crops systems. nized by the sticky mess. When disturbed, these aphids Considerable laboratoiy and field data dealing with actively jump from the plants. Summer winged forms chemical, biological, and cultural methods of controlling are produced in much larger numbers than the pea alfalfa insects are available. These data need to be closely aphid. interpreted with respect to their implications for inte- Damage to the alfalfa plant is of several types. The grated control and then applied in integrated pest man- possibility of virus transmission has been discussed by agement programs in the field. The breadth and depth several authors, but has never been verified. Many work- of research on alfalfa insect control and alfalfa produc- ers belie\e that the aphid is capable of producing a toxin tion in general have been sufficiently productive to im- which is injected into the alfalfa plants, helping to pro- plement some programs now. duce symptoms. Young plants of susceptible varieties can To facilitate better use of e.xisting literature in devel- tolerate very few aphids without being killed. The tre- oping pest management systems, bibliographies of the mendous amounts of honeydew produced ha\e created key pest species on alfalfa are being prepared in coopera- problems such as clogging of harvesting equipment. Mold tion with the Soybean Insect Research and Information growing on this honeydew reduces livestock acceptance Center fSIRIC) at the Illinois Natural Ilistoiy Survey of the alfalfa. Stunted plants, poor seed set, and short and University of Illinois. SIRIC has de\eloped a set stand life are typical symptoms. of computer programs for the IBM/360 at the Univer- The spotted alfalfa aphid is a one-host-plant aphid. sity of Illinois, which makes possible the retrie\al of liter- It has a continuous life cycle on alfalfa and normally ature citations associated with a subject or combination does not produce se.xual forms in the fall. This means of subjects. The bibliographies of the key alfalfa pests, that the best sur\ival of the aphid occurs in areas where starting with Therioaphis maculata have been stored on there is alfalfa grovs th during the entire year. The adult magnetic tape and are retrievable using the SIRIC ajjhids often crawl down around the base of the plant system. where they are capable of suniving during the winter Damage from the spotted alfalfa njjhid was first recog- unless the climate is too severe. In cold areas, there nized in the United States during 1954. When it was may be complete mortality. This is the basic reason that first reported, most of the workers believed that it was a the spotted alfalfa aphid is a problem primarily in form of the yellow clover aphid which had become warmer climates. Starting about 3 years after its initial adapted to alfalfa. Within a couple of years it was found introduction into the United States, a few sexual forms that this was not the case. The spotted alfalfa aphid was were noted during the fall of the year. These sexual apparently a new introduction into the United States forms ha\c never become numerous, but they are a pre- from the Near East. The first reports were from New lude to egg laying on alfalfa stems. There is evidence that the s])olted a])hid populations in the northern areas, This paper, in the Biological Notes scries, is piiblislicd ivith special project funds. Dr. D. W. Davis is a Professor of Entomology at Utah State Univer- such as South Dakota and Minnesota, have been gradu- sity. M. P. Nichols is a Research Associate. International Programs and Studies, University of Illinois. Dr. E. J. Armbrust is an Associate Entomol- ally selecting for larger numbers of these sexual forms. ogist at the Illinois Natural History Survey and Associate Professor of Ag- ricultural Entomolog>-, Illinois Agricultural Experiment Station. Even with these fall egg-laying aphids, Medicago spp. remain as the only hosts on which the insect can com- Rose and Mr. Rax-mond A. Kotek tv-ped the manuscript, plete its full cycle. Occasional collections have been and O. F. Glissendorf edited it. Their collaboration is made from other legumes. The aphids multiply ex- gratefully acknowledged. tremely rapidly during the summer, producing a large number of winged forms. These winged forms are car- ried by wind currents very readily and have been picked BIBLIOGRAPHY up at high elevations by aircraft. This summer distribu- !. Anonvmols. 1956. Control spotted alfalfa aphids with tion of winged forms can take place over several hun- malathion. American Cyanamid Co. Leaf). 14 p. illus. dred miles. maps. Control measures have taken three major pathways. 2. 1956. The newest threat to alfalfa; Spotted The first and probably most important of these has been alfalfa aphid. Utah Agr. Ext. Serv. Leaf!. 8. [8 p.] illus. the development of resistant alfalfa varieties. The resis- 3. 1959. New Kansas alfalfa resists spotted aphid. tant varieties are tolerant to the toxin of as well as the Crops Soils Mag. 12(2) :21. illus. feeding damage by the aphids. Several very successful 4. 1961. Field crop varieties for Arizona 1960. Ariz. Coop. Ext. Serv. Agr. Exp. Sta. Bull. .\-A. 16 parasites have been introduced into the United States p. illus. maps. and unquestionably these have been instrumental in 5. 1970. Soybean virus disease veaors. Miss. Agr. reducing the spotted alfalfa aphid damage in south- Forest. Exp. Sta. Annu. Rep. 83:33. western areas. In addition to the introduction of para- 6. Allen, W. .\., M. L. Bobb, J. M. Grayson, J. E. Rob- sites, quite a native number of the predators also aid erts, Sr., W. H. Robinson, and J. .\. AVeidh.\.\s. 1972. in biological control. The third major approach has been 1972 Virginia insect control guide. \'a. Polytcch. Inst. Ext. Div. Contr. Ser. 141. 118 illus. maps. with insecticides. Initially, most of the work involved p. 7. Ang.alet, G. \V. 1970. Population, parasites, and materials like parathion, but more recent chemical con- damage of the spotted alfalfa aphid in New Jersey, Delaware, trol has centered on the systemic insecticides. and the eastern shore of Mar\Iand. J. Econ. Entomol. An important aspect of the spotted alfalfa aphid biol- 63(1) :313-315. illus. refs. ogy is the rapidity in which it develops new biotypes or 8. B..\KER, W. A. 1955. The yellow clover aphid on alfalfa. localized forms. These biotypes have developed in re- Agr. Chem. 10(9) :60, 62, 122-123. sponse both to insecticides and to overcoming the resis- 9. Ball, H. J. 1958. The effect of visible spectrum irradi- ation on growth and de\elopmcnt in se\eral species tance of alfalfa varieties.