Evaluation of Inundative Releases of Eretmocerus eremicus and Encarsia formosa Beltsville Strain in Commercial Greenhouses for Control of Bemisia argentifolii (Hemiptera: Aleyrodidae) on Poinsettia Stock Plants

1999 ◽  
Vol 92 (4) ◽  
pp. 811-824 ◽  
Author(s):  
Mark S. Hoddle ◽  
Roy G. Van Driesche
Keyword(s):  
Bemisia Argentifolii ◽  
Encarsia Formosa ◽  
Eretmocerus Eremicus ◽  
Inundative Releases

Biological control of Bemisia argentifolii (Hemiptera: Aleyrodidae) on poinsettia with inundative releases of Eretmocerus eremicus (Hymenoptera: Aphelinidae): do release rates affect parasitism?

1998 ◽  
Vol 88 (1) ◽  
pp. 47-58 ◽  
Author(s):  
M.S. Hoddle ◽  
R.G. Van Driesche ◽  
J.P. Sanderson ◽  
O.P.J.M. Minkenberg
Keyword(s):  
Release Rate ◽  
Growing Season ◽  
Bemisia Argentifolii ◽  
Release Rates ◽  
High Release ◽  
Reproductive Rates ◽  
Eretmocerus Eremicus ◽  
Population Counts ◽  
Inundative Releases ◽  
Made In

AbstractThe effectiveness of inundative releases of the parasitoid Eretmocerus eremicus n. sp. Rose & Zolnerowich for control of Bemisia argentifolii Bellows & Perring on poinsettia in replicated experimental greenhouses was determined. We evaluated two release rates of E. eremicus: a low release rate (one female per plant per week, released in two greenhouses, in spring 1995) and a high release rate (three females per plant per week, released in two greenhouses, in spring 1994), each over a 14 week growing season. Each release trial had either one (1995) or two (1994) control greenhouses in which B. argentifolii developed on poinsettia in the absence of E. eremicus. Life-tables were constructed for B. argentifolii in the presence and absence of E. eremicus by using a photographic technique to follow cohorts of whiteflies on poinsettia leaves. Weekly population counts of whiteflies were also made. In the absence of E. eremicus, egg to adult survivorship of B. argentifolii on poinsettia was 75–81%. At the low release rate, egg to adult survivorship of B. argentifolii was 12% and parasitism was 34%. At the high release rate, egg to adult survivorship of B. argentifolii was 0.9% and parasitism was 10%. The average net reproductive rates (Ro) for populations of B. argentifolii in the absence of E. eremicus ranged from 20.5 to 26.1, indicating a rapidly increasing population density. Net reproductive rates for whitefly populations subject to parasitoid releases were 3.7 in the low release rate greenhouses, and 0.25 in the high release rate greenhouses, indicating substantially reduced B. argentifolii population growth. At week 14 of the trial, densities of immature whiteflies were lower in greenhouses at the low release rate when compared to the high release rate greenhouses. This was attributed to high levels of in-house reproduction by parasitoids at the low release rate.

Biological control ofBemisia argentifolii(Hemiptera: Aleyrodidae) on poinsettia with inundative releases ofEretmocerus eremicus(Hymenoptera: Aphelinidae): does varying the weekly release rate affect control?

1999 ◽  
Vol 89 (1) ◽  
pp. 41-51 ◽  
Author(s):  
M.S. Hoddle ◽  
J.P. Sanderson ◽  
R.G. Van Driesche
Keyword(s):  
Release Rate ◽  
Bemisia Argentifolii ◽  
Release Rates ◽  
Female Parasitoid ◽  
Affect Control ◽  
High Release ◽  
Reproductive Rates ◽  
Eretmocerus Eremicus ◽  
High Treatment ◽  
Inundative Releases

AbstractThe effectiveness of varying weekly release rates of the parasitoidEretmocerus eremicusRose & Zolnerowich for control ofBemisia argentifoliiBellows & Perring on poinsettias was determined. Two variable release rate strategies forE. eremicuswere evaluated: a low–high and a high–low release regimen. In the low–high treatment, one female parasitoid was released per plant per week for seven weeks, then the release rate was increased to five female parasitoids per plant per week for the remaining seven weeks of the trial. In the high–low treatment, five female parasitoids per plant per week were released for the first seven weeks, then the release rate was reduced to one female parasitoid per plant per week for the final seven weeks of the trial. Both release rates averaged three female parasitoids per plant per week. Life-tables were made forB. argentifoliiin the presence and absence of parasitoids. In the absence ofE. eremicus, egg to adult survivorship forB. argentifoliiwas 65%. In low–high release greenhouses, average egg to adult survivorship forB. argentifoliiwas 6% and parasitism was 28%. In high–low greenhouses, average egg to adult survivorship forB. argentifoliiwas 5% and parasitism was 16%. Average net reproductive rates forB. argentifoliiin the absence of parasitoids was 17 indicating a rapidly increasing population. Net reproductive rates were 1.46 and 1.24 for low–high and high–low release greenhouses, respectively, indicating substantially reducedB. argentifoliipopulation growth. At week 14 of the trial, densities of live nymphs and pupae were lower in high–low greenhouses when compared to low–high greenhouses. Better whitefly control is achieved with inundative releases ofE. eremicuswhen this natural enemy acts as a predator as opposed to a parasitoid.

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