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SUGAR-CANE LEAFHOPPER Perkinsiella saccharicida Kirkaldy --
Hemiptera, Delphacidae (Contacts) ----- CLICK on Photo to enlarge &
search for Subject Matter with Ctrl/F. GO TO ALL: Bio-Control Cases It was determined
by Kirkaldy that closely allied species of leafhopper occurred in Java, and
Perkins found leafhoppers on sugarcane cuttings just arrived from Queensland,
Australia. He determined by
correspondence and the exchange of specimens that the same P. saccharicida occurred in Cairns, Queensland, but did no
noticeable damage there, leading to a simple clue as to where to obtain
effective natural enemies. Perkins
and Koebele sailed for Queensland on May 11, 1904, and upon arrival in Brisbane
and Bundaberg, they immediately found the sugarcane leafhopper and a number
of parasitoids attacking it. Koebele
discovered the egg parasitoid, Paranagrus
optabilis Perkins which
played a dominant role in the early reduction of leafhopper in Hawaii. It was generally distributed in Queensland
and several shipments were made to Hawaii, but the slow transport by ship
caused the specimens to die or become weakened. Nevertheless, Terry on Oahu obtained a few direct colonization
of parasitoids in August, October and November 1904. Later Perkins stocked a breeding cage in
Australia, which arrived in Hawaii on December 14, 1904. The few parasitoids that survived the
journey were either kept for breeding purposes or liberated directly in the
field. At the close of 1905 this
parasitoid, Panagrus optabilis was recovered in the
field, and it became widespread and abundant in 1906-1907, followed by a
significant reduction in leafhopper densities. At the same time, a closely related species, Anagrus frequens Perkins, was found to be established, presumably
from the late 1904 releases made by Terry, but it was judged to be of small
importance. Another species, Ootetrastichus beatus Perkins was discovered
in Fiji by Koebele during his return voyage from Australia. This parasitoid became rapidly established
and spread throughout Hawaii, but never assumed a prominent role there. A Dr. Frederick
Muir was then hired to do additional foreign collections, due to the failing
health of Albert Koebele. In March
1906, Muir collected the parasitoid Haplogonatopus
vitiensis Perkins in Fiji,
which became established in Hawaii but did not add appreciably to the control
level. In China at Mei Chow he found Pseudogonatopus hospes Perkins, which after
much difficulty he was able to ship living specimens to Hawaii in December
1906 and early 1907. This parasitoid
became established and did add to the biological control level in
Hawaii. In 1907-1916 Muir explored
throughout the Malay archipelago, The Philippines, New Guinea, Formosa and
Japan for several Hawaiian projects, but continued to focus his attention on
sugarcane leafhopper. In Formosa
during February 1916 he discovered another egg parasitoid, Ootetrastichus formosanus Timberlake, which he
transported to Hawaii. A culture was
established and later field colonization added still more to the level of
biological control. Although the
activities of five parasitoid species in Hawaii produced excellent biological
control on most sugar plantations, there were sporadic outbreaks of
leafhopper in some areas, especially where heavy rainfall occurred throughout
the year. It was obvious by
1919 that in the wetter areas such as Hilo, the leafhopper remained a
constant problem. It was concluded
that additional natural enemies should be sought which could perform under very
wet conditions. Therefore, in May
1919 Muir went to Queensland, Australia for more detailed field studies. He discovered Cyrtorhinus mundulus
(Bredd), which is a highly effective predator of leafhopper eggs. This predator had been regarded as a phytophagous
species prior to Muir's research.
Previously, Koebele and Perkins, as well as Muir and others, had
previously overlooked this predator principally because it belongs to the
family Miridae in which most of the species are phytophagous (DeBach 1974). The discovery of
the predator came only after a very thorough scientific investigation, and is
detailed by Muir (1931) as follows:
"In 1919 I went to Australia to make further investigations of
the habits of a small carabid beetle which I had noted previously preying on Perkinsiella, but owing to the
very exceptionally dry season these beetles were so scarce I could make no
progress with this work, so turned my attention to other phases of the
question. It soon came to my notice
that a very large percentage of Perkinsiella
eggs were dead and attacked by a fungus, a fact that Perkins noted in
1903-4. I found the fungus in the
form of yeast-like spores present in old egg shells from which the young had
hatched, which could be recognized by the egg cap being off, and also in
unhatched eggs, which in itself was intriguing. In moist cells these spores gave rise to mycelia and then to
fruiting bodies and yeast-like spores similar to the original ones. Further investigation showed that these
spores were present in all young and adult leafhoppers in the body cavity,
where thy multiplied by division; that they passed through the walls of the
ovarian tubes and entered the young eggs, congregating in a small round ball
at one end of the egg, and eventually becoming mostly incorporated into the
embryo. As these were universal, it
then became evident that the fungus could not be the cause of the dead eggs,
as otherwise all could be destroyed.
Upon killing the egg by pricking, the spores developed. This led to observations in the field to
discover what led to the death of the egg.
The fact was then revealed the Cyrtorhinus
mundulus pierced the egg and
sucked it. In some cases the egg was
sucked nearly dry, in others the egg was only pierced and very little sucked,
but it led to the death of the egg and to the development of the fungus. Thus the fungus is symbiotic and passes
from adult to embryo and is always present.
Whether the leafhopper can be reinfected by spores developed outside
is not known. It is highly probable
that the spores play some part in the metabolism of the insect, as similar
bodies are found in all species of Delphacidae and many other
Homoptera." In June 1920 Muir
returned with a cage of living Cyrtorhinus
mundulus and following
careful studies to eliminate any possible dependency on sugarcane leaves, but
required leafhopper eggs for food, liberations were made in July. Dr. J. G. Myers, who was in charge of the
test for phytophagous habits, hesitated considerably before recommending
liberations of the predator in Hawaii.
Once approved, additional predator material was obtained from Fiji,
and following establishment in Hawaii the sugarcane leafhopper became an
insignificant pest. For further details
on biological control effort and biologies of host and natural enemies,
please also see the following (Perkins 1903, 1905-06; Pemberton 1919, 1920;
Swezey 1919, 1936, Muir 1920, Timberlake 1927, Verma 1955, Williams 1958,
Clausen 1978). REFERENCES: [Additional references may be found at: MELVYL
Library ] Clausen, C.
P. 1978. Delphacidae. In: C. P. Clausen (ed.), Introduced Parasites
and Predators of Arthropod Pests and Weeds.
U. S. Dept. Agric., Agric. Handbk. No. 480.
545 p. DeBach,
P. 1974. Biological Control
by Natural Enemies. Cambridge Univ.
Press, London & New York. 323 p. Muir,
F. 1920. Report of
entomological work in Australia, 1919-1920.
Hawaiian Planters Rec. 23:
125-30. Muir, F.
1931. Introduction in: The
Insects and Other Invertebrates of Hawaiian Sugar Cane Fields. Francis X. Williams. Expt. Sta. Hawaiian
Sugar Planters Assoc. 400 p. Pemberton, C. E. 1919. Leafhopper
investigations in Hawaii. Hawaii.
Planters' Rec. 21: 194-221. Pemberton, C. E. 1920. Insecticide
sprays: their relation to the control
of leafhoppers by parasites. Hawaii.
Planters' Rec. 22: 293-95. Pemberton, C. E. 1948. History of the
Entomology Department Experiment Station. HSPA 1904-45. Hawaiian Planters
Record 52(1): 53-90. Perkins, R. C. L. 1903. The leaf-hopper
of the sugar cane. Hawaii Bd. Commrs.
Agric. & Forestry Div. Ent. Bull. 1.
38 p. Perkins, R. C. L. 1905-06. Leaf-hoppers
and their natural enemies. Hawaii.
Sugar Planters' Assoc. Expt. Sta., Div. Ent. Bull. I, Pts. 1-4, 6, 8 &
10. Swezey, O. H.
1919. Notes on the Chinese
dryinid parasite of the sugarcane leafhopper. Hawaii. Planters' Rec. 20:
239-42. Swezey, O. H.
1936. Biological control of
the sugar cane leafhopper in Hawaii.
Hawaii. Planters' Rec. 40:
57-101. (Reprinted as Hawaii.
Sugar Planters' Assoc. Expt. Sta., Ent. Ser. Bull. 21). Timberlake, P. H. 1927. Biological
control of insect pests in the Hawaiian Islands. Hawaii. Ent. Soc. Proc. 4:
529-56. Verma, J. S. 1955. Biological studies
to explain the failure of Cyrtorhinus
mundulus (Breddin) as an
egg-predator of Peregrinus maidis (Ashmead) in
Hawaii. Hawaii. Ent. Soc. Proc.
15: 623-34. Williams, J. R. 1958. Cane pests. Mauritius Sugar Indus. Res. Inst. Rept.
1957: 66-71. |
