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SPOTTED
ALFALFA APHID Therioaphis maculata (Buckton) -- Homoptera,
Aphididae (Contacts) ----- CLICK on Photo to enlarge &
search for Subject Matter with Ctrl/F. GO TO ALL: Bio-Control Cases This
aphid, indigenous to the Old World where it attacks alfalfa and some clovers
(Manglitz & Russell 1974), spread through the southwestern United States
and California rapidly causing much damage to alfalfa (Smith 1959). The presence in alfalfa of native aphid
predators capable of reproducing during the summer months and the
availability of a selective insecticide made possible the evolution of an
integrated control program that has proved highly satisfactory in control of
the spotted alfalfa aphid (Smith & Hagen 1959, Stern et al. 1959, Stern
& van den Bosch 1959, Hagen et al. 1969). Most aphid predators reproduce in the spring and fall months in
California, but relatively few are reproductive during the summer months,
probably because during their evolutionary history aphids have been scarce on
low vegetation during the hot dry California summers. The main aphid predators in California are
ladybird beetles in the genus Hippodamia,
and in most valleys of California H.
convergens and H. quinquesignata are the two most important species (Hagen
1962, Hagen & van den Bosch 1968, Smith & Hagen 1965, 1966). In the Imperial Valley, in addition to H. convergens, Cycloneda
sanguinea L. is active
against T. trifolii throughout the year
(Dickson et al. 1955). Three exotic
parasitoids were introduced from the Old World into California in
1955-56: Aphelinus asychis
Walker, Praon exsoletum and Trioxys complanatus. By
1959 all three species were established in most of the alfalfa districts, and
were contributing significantly to biological control of the aphid (van den
Bosch et al. 1959). Trioxys complanatus was generally dominant over the other two
species. Phenologically, Trioxys is very active during
spring, autumn and winter, while P.
exsoletum largely confines
its activity to the spring and fall. Aphelinus is most active during
the cooler, more humid times of the year (van den Bosch et al. 1964). In total they greatly supplement one
another, relative to the whole range of the aphid in California. Bioclimatic studies by Messenger (1972)
suggested that climate is the key feature in their pattern of distribution. In areas of overlap, competition between
the parasitoids can occur, the outcome of which can be influenced by climate. The three
parasitoids were also released in Arizona during 1955-57, and recoveries of
each species were made and T.
complanatus became well
established in southern Arizona where it is a substantial control factor
(Barnes 1960). In Kansas, either the
native A. semiflavus of A. asychis from France and India were colonized in 1956. Aphids on alfalfa in greenhouses became
heavily parasitized by this culture, but it is not certain if the Aphelinus involved was the
native or the introduced A. asychis (Simpson et al.
1959). In the eastern
United States, the three parasitoids were cultured in the USDA Moorestown
laboratory in 1956 and released against the yellow clover aphid, Therioaphis trifolii (Monell), which mainly
attacks red clovers. The original
stock of P. exsoletum came from France, A. asychis from Israel, and T. complanatus
from the yellow clover aphid in New Jersey.
It is believed that the latter parasitoid had already been
accidentally introduced into the United States (Mackauer & Stary
1967). Angalet (1970) reported all
three species as parasitizing spotted alfalfa aphid in New Jersey, Delaware
and Maryland. Maximum parasitism in
autumn was 51%. Spotted alfalfa aphid
in southern California was found susceptible to infection by five species of Entomophthora, two of which
also occur in the Old World.
Epizootics in high populations were widespread in the autumn of 1955
(hall & Dunn 1957). Please see the following for additional detail on
biological control effort and biologies of host and natural enemies (Harpaz
1955, van den Bosch 1957, Hall & Dunn 1958, Schlinger & Hall 1959,
Hall et al. 1962, Force & Messenger 1964a,b, 1965, 1968; Mackauer & Finlayson
1967, Messenger 1968). REFERENCES: [Additional references may be found at: MELVYL
Library ] Angalet, G. W. 1970. Population, parasites, and damage of the spotted
alfalfa aphid in New Jersey, Delaware and the eastern shore of Maryland. J. Econ. Ent. 63: 313-15. Barnes, O. L. 1960. Establishment of imported parasites of the
spotted alfalfa aphid in Arizona. J. Econ.
Ent. 53: 1094-96. Dickson, R. C., E. F. Laird, Jr. & G. R. Pesho. 1955.
The spotted alfalfa aphid (yellow clover aphid on alfalfa). Hilgardia 24: 93-118. Force, D. C. & P. S. Messenger. 1964a. Duration of
development, generation time, and longevity of three hymenopterous parasites
of Therioaphis maculata, reared at various
constant temperatures. Ann. Ent. Soc.
Amer. 57: 405-13. Force, D. C. & P. S. Messenger. 1964b. Fecundity,
reproductive rates, and innate capacity for increase of three parasites of Therioaphis maculata (Buckton). Ecology 45: 706-15. Force, D. C. & P. S. Messenger. 1965. Laboratory
studies on competition among three parasites of the spotted alfalfa aphid, Therioaphis maculata (Buckton). Ecology 46: 953-59. Force, D. C. & P. S. Messenger. 1968. The use of
laboratory studies of three hymenopterous parasites to evaluate their field
potential. J. Econ.
Ent. 61: 1374-78. Hagen, K. S. 1962. Biology and ecology of predaceous
Coccinellidae. Ann. Rev. Ent.
7: 289-326. Hagen, K. S. & R. van den Bosch. 1968. Impact of
pathogens, parasites, and predators on aphids. Ann. Rev. Ent. 13:
325-84. Hagen, K. S., R. van den Bosch & D. L.
Dahlsten. 1969.
The importance of naturally-occurring biological control in the
western United States. In: C. B. Huffaker (ed.), Biological Control. Plenum / Rosetta Press, New York. 511 p. Hall, I. M. & P. H. Dunn. 1957. Entomophthorous fungi parasitic
on the spotted alfalfa aphid.
Hilgardia 27: 159-81. Hall, I. M. & P. H. Dunn.
1958. Artificial dissemination
of entomophthorous fungi pathogenic to the spotted alfalfa aphid in
California. J. Econ.
Ent. 51: 341-44. Hall, J. C., E. I. Schlinger & R. van
den Bosch. 1962.
Evidence for the separation of the "sibling species" Trioxys utilis and Trioxys
pallidus (Hymenoptera:
Braconidae, Aphidiinae). Ann. Ent. Soc.
Amer. 55: 566-68. Harpaz, I. 1955. Bionomics of Therioaphis maculata
(Buckton) in Israel. J. Econ.
Ent. 48: 668-71. Mackauer, M. J. P. & T. Finlayson. 1967. The hymenopterous parasites
(Hymenoptera: Aphidiidae et Aphelinidae) of the pea aphid in eastern North
America. Canad. Ent. 99: 1051-82. Mackauer, M. & P. Starư.
1967. "Hym.
Ichneumonoidea: World Aphidiidae.
Index of Entomophagous Insects.
LeFrancois, Paris. p. 195. Manglitz, G. R. & L. M. Russell. 1974. Cross matings
between Therioaphis maculata (Buckton) and T. trifolii (Monell) (Hemiptera: Homoptera: Aphididae) and
their implications in regard to the taxonomic status of the insects. Proc. Ent. Soc. Wash. 76: 290-96. Messenger, P. S. 1968. Bioclimatic studies of the aphid parasite Praon exsoletum: I.
Effects of temperature on the functional response of females to
varying host densities. Ann. Ent. Soc.
Amer. 100: 728-41. Messenger, P. S. 1972. Climatic limitations to biological
controls. Proc. Tall Timbers Conf.
Ecol. Anim. Contr. Habitat Management 3:
97-114. Schlinger, E. I. & J. C. Hall. 1959. A synopsis of the
biologies of three imported parasites of the spotted alfalfa aphid. J. Econ. Ent. 52: 154-57. Simpson, R. G., C. C. Burkhardt, F. G. Maxwell & E. E.
Ortman. 1959. A chalcid parasitizing spotted alfalfa
aphids and green bugs in Kansas. J. Econ.
Ent. 52: 537-38. Smith, R. F. 1959. The spread of the spotted alfalfa aphid Therioaphis maculata (Buckton) in
California. Hilgardia 26: 647-85. Smith, R. F. & K. S. Hagen.
1959. The integration of
chemical and biological control of spotted alfalfa aphid. Impact of commercial insecticide
treatments. Hilgardia 29: 131-54. Smith, R. F. & K. S. Hagen.
1965. Modification of the
natural regulation of aphids by local climates in California. Proc. XII Intern. Congr. Ent., London (1964): 372-74. Smith, R. F. & K. S. Hagen.
1966. Natural regulation of
alfalfa aphids in California, p. 297-315.
In: I. Hodek (ed.), Ecology of Aphidophagous
Insects. W. Junk Publ., The Hague,
Netherlands. 360 p. Stern, V. M. & R. van den Bosch. 1959. The integration of
chemical and biological control of the spotted alfalfa aphid. Field experiments on the effects of
insecticides. Hilgardia
29: 103-30. Stern, V. M., R. F. Smith, R. van den Bosch
& K. S. Hagen. 1959.
The integration of chemical and biological control of the spotted
alfalfa aphid. The integrated control
concept. Hilgardia 29: 81-101. van den Bosch, R.
1957. The spotted alfalfa
aphid and its parasites in the Mediterranean region, Middle East and East
Africa. J. Econ.
Ent. 50: 352-56. van den Bosch, R., E. I. Schlinger, E. J.
Dietrick & J. C. Hall. 1959. The
role of imported parasites in the biological control of the spotted alfalfa
aphid in southern California. J. Econ.
Ent. 52: 142-54. van den Bosch, R., E. I. Schlinger, E. J.
Dietrick, J. C. Hall & B. Puttler.
1964. Studies on succession, distribution, and
phenology of imported parasites of Therioaphis
trifolii (Monell) in
southern California. Ecology 45: 601-21. |