Ovicide in the whitefly parasitoid, Encarsia formosa

2000 ◽  
Vol 60 (2) ◽  
pp. 217-226 ◽  
Author(s):  
Jessa F. Netting ◽  
Martha S. Hunter
Keyword(s):  
Encarsia Formosa

scholarly journals Phototoxicity of Ultraviolet-A against the Whitefly Bemisia tabaci and Its Compatibility with an Entomopathogenic Fungus and Whitefly Parasitoid

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Muhammad Musa Khan ◽  
Ze-Yun Fan ◽  
Dylan O’Neill Rothenberg ◽  
Jing Peng ◽  
Muhammad Hafeez ◽  
...  
Keyword(s):  
Biological Control ◽  
Bemisia Tabaci ◽  
Exposure Time ◽  
Entomopathogenic Fungus ◽  
Light Exposure ◽  
Adult Emergence ◽  
Biological Control Agents ◽  
Encarsia Formosa ◽  
Parasitism Rate ◽  
Invertebrate Pests

Ultraviolet (UV) radiation significantly affects insect life and, as a result, has been widely used to control different invertebrate pests. The current results demonstrate that when Bemisia tabaci first instar nymphs are exposed to UV-A light for 12, 24, 48, and 72 h, their developmental and biological parameters are negatively affected by UV-A exposure; the effect increased with an increase in exposure time. We hypothesized that UV-A light is compatible with other biological control agents. Results showed that when the entomopathogenic fungus Cordyceps fumosorosea was applied to third instar nymphs of B. tabaci previously exposed to UV-A light, the LC50 was 3.4% lower after 72 h of exposure to UV-A light compared to the control. However, when the fungus was exposed to UV-A light, its virulence decreased with an increase in UV-A exposure time. The parasitism rate of Encarsia formosa against 24 h UV-A-exposed third instar nymphs of B. tabaci increased while the adult emergence from parasitized nymphs was not affected after UV-A light exposure. Parasitism rate was significantly reduced however following E. formosa exposure to UV-A light; but again, adult emergence was not affected from parasitized nymphs. The percentage mortality of E. formosa increased with increasing exposure time to UV-A light. The enzyme activity of SOD, CAT, GST, and AChE and the energy reserve contents were negatively affected due to UV-A exposure. Collectively, this study has demonstrated that UV-A light significantly suppresses the immune system of B. tabaci and that UV-A light is compatible with other biological control agents if it is applied separately from the biological agent.

Improvement on Natural Enemies of Bemisia tabaci (Hemiptera: Aleyrodidae) Using Extracts of Agrimonia pilosa

2019 ◽  
Vol 112 (4) ◽  
pp. 1581-1586
Author(s):  
Huifang Guo ◽  
Yufeng Qu
Keyword(s):  
Biological Control ◽  
Bemisia Tabaci ◽  
Natural Enemies ◽  
Insect Pests ◽  
Ethanol Extract ◽  
Pathogenic Fungi ◽  
Melia Azedarach ◽  
Encarsia Formosa ◽  
Ethanol Extracts ◽  
And Control

Abstract Compared with the numerous natural enemies against insect pests that have been identified, the commercialization of natural biological control resources remains very limited. To increase the use of natural enemies for biological control, determining how to improve the low efficacy, slow speed, and high cost of natural enemies is very important. Mediterranean species of The whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodoidea), increasingly threatens many crops in China, and control primarily depends on chemical insecticides. Here, the effect of ethanol extracts from two plants, Agrimonia pilosa (Ledeb) (Rosales: Rosaceae) and Melia azedarach (Linn) (Meliaceae: Melia), on predominant natural enemies of B. tabaci was investigated using a leaf dipping or spraying method. The results showed that the ethanol extract of A. pilosa significantly improved the infectivity of the fungus Isaria javanica (Friedrichs & Bally) (Ascomycota: Hypocreales), and the mortality of whiteflies caused by the combination of fungus (105 spores/mL) with the extract of A. pilosa (2 mg/mL dried powder of A. pilosa containing 0.0942 mg/mL total polyphenols) was 81.6%, which was significantly higher than that caused by the fungus only. However, the ethanol extract of M. azedarach had no effect on fungus infectivity. Additionally, insecticide tolerance of the predator Pardosa pseudoannulata was also significantly improved by the extract of A. pilosa. The longevity of the parasitoid Encarsia formosa was not affected by the extracts. These findings indicate that the extract of A. pilosa played a dual role that included improving pathogenic fungi infectivity and insecticidal tolerance of a predator and thus could be a synergist in the biological control of B. tabaci.

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