EFFECTS OF INITIAL DENSITIES AND PERIODS OF INFESTATION ON THE GROWTH-FORMS OF A HOST AND PARASITE POPULATION

1960 ◽  
Vol 38 (6) ◽  
pp. 1063-1077 ◽  
Author(s):  
T. Burnett
Keyword(s):  
Trialeurodes Vaporariorum ◽  
Parasite Population ◽  
Growth Forms ◽  
Encarsia Formosa

Initial densities and periods of infestation of adults of Trialeurodes vaporariorum and its chalcid parasite Encarsia formosa influence subsequent fluctuations in numbers of adults of both host and parasite.

AN INSECT HOST–PARASITE POPULATION

1960 ◽  
Vol 38 (1) ◽  
pp. 57-75 ◽  
Author(s):  
Thomas Burnett
Keyword(s):  
General Trend ◽  
Trialeurodes Vaporariorum ◽  
Parasite Population ◽  
Insect Host ◽  
Growth Forms ◽  
Encarsia Formosa ◽  
Tomato Plants ◽  
Sources Of Variation ◽  
Host Parasite

Eight populations of Trialeurodes vaporariorum and Encarsia formosa were propagated on tomato plants in the greenhouse for about eight months. Although there was some variation in the growth-forms of host and parasite among the experiments, the general trend in each experiment was one of fluctuations of slightly, but distinctly, increasing amplitude. As extraneous sources of variation had only a slight influence on the growth-forms, the fluctuations resulted from host–parasite interaction. The T. vaporariorum – E. formosa system, is well suited for an investigation of the principles of host–parasite interaction.

HOST LARVAL MORTALITY IN AN EXPERIMENTAL HOST–PARASITE POPULATION

1964 ◽  
Vol 42 (5) ◽  
pp. 745-765 ◽  
Author(s):  
T. Burnett
Keyword(s):  
Larval Mortality ◽  
Trialeurodes Vaporariorum ◽  
Parasite Population ◽  
Rapid Decline ◽  
Encarsia Formosa ◽  
Host Protection ◽  
Host Mortality ◽  
Host Parasite ◽  
Parasite Populations ◽  
Two Populations

Two populations of Trialeurodes vaporariorum (Westw.) and its chalcid parasite Encarsia formosa Gahan were reared on tomato plants in the greenhouse at 72–76 °F for 26 weeks. Although the abundance of both species fluctuated with peaks of increasing amplitude, the population that was initially larger remained so throughout the period of sampling because the parasite inflicted similar rates of mortality in both cases. The fluctuations of the two separate populations were synchronized throughout the period of propagation. Host mortality, which resulted either from almost immediate killing of host scales following attack by adult parasites or from death of host larvae following parasitization and development of parasite progeny, was determined by parasite density, host size, and possibly by a number of other factors such as the age structure of host larval populations, age of adult parasites, and succulence of leaves on which the host larvae developed. The interaction of host and parasite produced cycles in the age structures of host and parasite populations that, in turn, influenced the interaction of the two species. The death of host larvae following attack by adult parasites was a form of host protection, as it ensured the rapid decline in the abundance of the parasite population and was, therefore, the primary factor in the maintenance of the host–parasite system.

ASPECTS OF THE INTERACTION BETWEEN A CHALCID PARASITE AND ITS ALEURODID HOST

1967 ◽  
Vol 45 (4) ◽  
pp. 539-578 ◽  
Author(s):  
T. Burnett
Keyword(s):  
Larval Mortality ◽  
Trialeurodes Vaporariorum ◽  
Host Population ◽  
Population Variation ◽  
Encarsia Formosa ◽  
Greenhouse Whitefly ◽  
Parasite Abundance ◽  
Tomato Plants ◽  
Host Mortality ◽  
Dominant Process

Three populations of the greenhouse whitefly, Trialeurodes vaporariorum, and its chalcid parasite Encarsia formosa were propagated each year for three consecutive years on tomato plants in the greenhouse. The abundance of the host and parasite species fluctuated either with peaks of increasing amplitude, with peaks of decreasing amplitude, or with irregular peaks. The dominant process in the interaction was the occurrence of two qualitatively different types of host larval mortality: (a) parasitization, and (b) almost immediate killing after attack by adult parasites. Fluctuations in host and parasite abundance resulted from the almost immediate killing of small host larvae and the death of the short-lived adult parasites. The parasite population tended to destroy similar percentages of host populations of different densities but host mortality was also related to the age structure of the host population. Variation in host reproduction, caused by differences in rearing temperature and by seasonal variation in the physical environment, influenced host and parasite densities.

The parasite-host relationship between Encarsia formosa (Hym., Aphelinidae) and Trialeurodes vaporariorum (Horn., Aleyrodidae)

2009 ◽  
Vol 93 (1-5) ◽  
pp. 258-279 ◽  
Author(s):  
Mariek H. Eggenkamp-Rotteveel Mansveld ◽  
J. C. van Lenteren ◽  
F. J. M. Ellenbroek ◽  
J. Woets
Keyword(s):  
Trialeurodes Vaporariorum ◽  
Encarsia Formosa

An Important Parasite of the Greenhouse White-fly (Trialeurodes vaporariorum, Westwood)

1927 ◽  
Vol 17 (3) ◽  
pp. 301-308 ◽  
Author(s):  
Edward R. Speyer
Keyword(s):  
Low Temperatures ◽  
Trialeurodes Vaporariorum ◽  
Hydrocyanic Acid ◽  
Encarsia Formosa ◽  
Single Female ◽  
Acid Gas ◽  
Pests And Diseases ◽  
History Of ◽  
Chalcid Wasp ◽  
Important Parasite

1.—Encarsia formosa, Gahan, is a Chalcid wasp that parasitises the white-fly, Trialeurodes vaporariorum, Westw., a single female ovipositing in 50 or more young pupae of the host. The larvae of the parasite, on hatching from the egg, destroys the white-fly pupa, the skin of which becomes black in colour, thus distinguishing the parasitised pupa from the normal white scales and pupa of the white-fly.2.—The parasite is parthenogenetic, males, probably impotent, only appearing when temperatures are low.3.—The life-history of the parasite occupies at least 28 days, and adults may remain in the scales for some time before cutting their way out by a circular hole in the roof of the scale. The adult is capable of travelling over large areas in glasshouses.4.—Low temperatures militate seriously against the increase of the parasite, which is probably a tropical insect and has possibly been imported into this country from India.5.—Fumigation with hydrocyanic acid gas, as practised commercially for the control of white-fly, does not affect the parasites.6.—The parasite is best distributed by detaching the black pupae of white-fly from the foliage, though 20 per cent, may be injured in this way. An almost complete emergence is obtained by cutting branches from plants and pinning them to the plants in houses where distribution is desired, but this involves risk of infecting the houses with various pests and diseases.

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