Biological effects of Bacillus thuringiensis on the egg parasitoid, Trichogramma evanescens

1985 ◽  
Vol 6 (2) ◽  
pp. 145-148 ◽  
Author(s):  
H. S. Salama ◽  
F. N. Zaki

AbstractFeeding of the adult parasite of Trichogramma evanescens Westwood on a honey solution containing 500 μg of Bacillus thuringiensis var. galleriae HD-129 for 4–5 days had no effect on their longevity, productivity or their capability to parasitize the host eggs of Spodoptera littoralis (Boisdüvalle) or Anagasta kuehniella Zeller. After spraying the freshly laid host eggs with B. thuringiensis at the same concentration, a significant decrease was observed in the percentage of parasitism. No deleterious effects were observed in the development of the immature stages of the parasite and the percentage of its emergence, as affected by B. thuringiensis, when applied to the host eggs before or after parasitism.

2017 ◽  
Vol 16 (1) ◽  
pp. 43 ◽  
Author(s):  
DANIEL SPAGNOL ◽  
ANDERSON DIONEI GRÜTZMACHER ◽  
RODOLFO VARGAS CASTILHOS ◽  
RAFAEL ANTÔNIO PASINI ◽  
RONALDO ZANTEDESCHI ◽  
...  

RESUMO - Plantas de milho transgênicas que expressam toxinas da bactéria Bacillus thuringiensis (Bt) são uma alternativa para o controle de insetos-praga na cultura. No entanto, estas toxinas podem ser encontradas no pólen do milho, e organismos não alvo, como os inimigos naturais, podem ser prejudicados. Assim, o objetivo deste trabalho foi avaliar o efeito do pólen de três híbridos de milho transgênicos sobre parâmetros biológicos de adultos do parasitoide de ovos Trichogramma pretiosum em condições laboratoriais. Fêmeas recém-emergidas de T. pretiosum foram individualizadas em tubos de Duran contendo como alimento mel acrescido do pólen dos híbridos de milho transgênico AG 8011 YG (Cry1Ab), AS 1551 VT PRO (Cry1A. 105 + Cry 2Ab2) e Status Viptera (Vip3Aa20), e de seus respectivos isogênicos convencionais. Diariamente, foram ofertados, em cada tubo, ovos de Anagasta kuehniella para parasitismo. Os parâmetros avaliados foram: longevidade das fêmeas expostas ao pólen, taxa de parasitismo total, taxa de emergência e razão sexual da progênie. Os híbridos transgênicos: AG 8011 YG (Cry1Ab), AS 1551 VT PRO (Cry1A. 105 + Cry 2Ab2) e Status Viptera (Vip3Aa20), bem como seus isogênicos convencionais, não causaram efeitos deletérios sobre a longevidade e capacidade de parasitismo das fêmeas de T. pretiosum expostas aos respectivos pólens. A emergência e razão sexual da progênie também não foram negativamente afetadas, possibilitando assim a compatibilização dos transgênicos avaliados com o controle biológico natural e aplicado exercido por este parasitoide.Palavras-chave: Bacillus thuringiensis, transgenia, manejo integrado de pragas, controle biológico, Zea mays.COMPATIBILITY OF TRANSGENIC CORN WITH THE PARASITOID Trichogramma pretiosumABSTRACT - Transgenic corn expressing Bacillus thuringiensis (Bt) toxins is an alternative for pest control in corn fields. However, some non-target organisms such as natural enemies can be impaired by corn pollen containing toxins. Therefore, the aim of this work was to evaluate the effect of the pollen from three transgenic corn varieties on biological parameters of the egg parasitoid Trichogramma pretiosum under laboratorial conditions. Emerged females of T. pretiosum were placed into Duran tubes and fed with honey + pollen of corn hybrids AG 8011 YG (Cry1Ab), AS 1551 VT PRO (Cry1A. 105 + Cry 2Ab2) and Status Viptera (Vip3Aa20), as well as their respective isogenic. Daily, eggs of Anagasta kuehniella were offered in each tube for parasitism. The parameters evaluated were longevity of females exposed to pollen, total parasitism, progeny emergency and sex ratio. The transgenic hybrids AG 8011 YG (Cry1Ab), AS 1551 VT PRO (Cry1A. 105 + Cry 2Ab2), Status Viptera (Vip3Aa20) and their isogenic showed no deleterious effect on longevity and parasitism capacity of T. pretiosum females exposed to respective pollen. Emergency and sex ratio from progeny were also not adversely affected, thus enabling the compatibility of the evaluated transgenic with biological control by this parasitoid.  Keywords: Bacillus thuringiensis, transgenes, integrated pest management, biological control, Zea mays.


2019 ◽  
Vol 29 (1) ◽  
Author(s):  
Naglaa F. Abdel-Hameid ◽  
I. R. M. Elzoghby ◽  
A. L. Mehany ◽  
W. A. A. Sayed

AbstractThe performance of parasitism by the egg parasitoid, Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) on eggs of Angoumois grain moth, Sitotroga cerealella Olivier (Lepidoptera: Gelechiidae) was investigated under cold storage and gamma irradiation treatments of the host eggs. Cold storage treatment could improve the parasitoid mass rearing techniques and reduced the costs of biological control programs, while gamma irradiation might be used as a supplementary support at the times of high demand. The suitability of the S. cerealella eggs, stored at – 20 °C for 0.5, 1, or 2 h. as a host for T. evanescens was evaluated. The sensitivity of S. cerealella eggs to gamma irradiation treatments and the acceptability of irradiated eggs for parasitism by T. evanescens females for the parental P and F1 generations were examined. The results revealed that parasitism was drastically reduced more than adult’s emergence and sex-ratio (% of females) after cold storage periods of S. cerealella eggs. Moreover, the parasitism percentages were relatively reduced to (97.1, 96.1, 93.03, and 92.7 %) after irradiating the S. cerealella eggs at 40, 60, 80, and 100 Gy, respectively than the control (97.3% emergence). The percentages of emergence and females’ percent were slightly decreased by gamma irradiation doses, while, equal preferred by the F1 generation of parasitoid that produced from irradiated S. cerealella eggs.


2003 ◽  
Vol 27 (2) ◽  
pp. 261-270 ◽  
Author(s):  
Geraldo Andrade Carvalho ◽  
José Roberto Postali Parra ◽  
Gilberto Casadei Baptista

A bioatividade de dezoito produtos químicos utilizados no controle de pragas e doenças do tomateiro, sobre duas linhagens de Trichogramma pretiosum Riley, 1879 (L9=Alegre, ES e L10= Venda Nova do Imigrante, ES), nas gerações F1 e F2, foi investigada em laboratório. Ovos de Anagasta kuehniella (Zeller) contendo o parasitóide em diferentes estágios de desenvolvimento (ovo-larva, pré-pupa e pupa) foram tratados por meio de imersão nas respectivas caldas químicas. Os inseticidas triflumuron, clorfluazuron, deltametrina, Bacillus thuringiensis, lambdacialotrina, teflubenzuron, acefato, pirimicarb e ciromazina, e os fungicidas benomil, iprodiona, clorotalonil e dimetomorf, independente da linhagem, não reduziram a longevidade das fêmeas de T. pretiosum da geração F1. Os inseticidas abamectin, cartap, metamidofós e lambdacialotrina afetaram a razão sexual de indivíduos da geração F1, e não reduziram a taxa de emergência de parasitóides da F2, independente do estágio de desenvolvimento e da origem da população de T. pretiosum. Parasitóides de Venda Nova do Imigrante, ES (L10) mostraram-se mais susceptíveis que os de Alegre, ES (L9) aos efeitos dos compostos avaliados. De modo geral, a fase de pupa de T. pretiosum, independente da população, apresentou maior tolerância aos produtos testados. Recomenda-se a realização de novos testes para outras populações desse parasitóide que serão utilizadas no controle de pragas, pois podem responder de forma diversa aos produtos fitossanitários avaliados.


2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Dhekra Mhalla ◽  
Dalel Ben Farhat-Touzri ◽  
Slim Tounsi ◽  
Mohamed Trigui

The increasing insect resistance against Bacillus thuringiensis delta-endotoxins is a serious problem which makes it urgent to look for new eco-friendly strategies. Combining these toxins with other biomolecules is one of the promising strategies against insect pests. In this work, we evaluated the bioinsecticidal potential of Rumex tingitanus extracts and B. thuringiensis strain BLB250 against Spodoptera littoralis (Lepidoptera: Noctuidae) larvae. The chemical composition of the hexane extract, the most active fraction, was analyzed to validate the correlation between chemical composition and biological activity. Among the tested extracts, only the hexanic extract showed toxicity against first and second instar larvae with LC50 of 2.56 and 2.95 mg g−1, respectively. The Bacillus thuringiensis BLB250 delta-endotoxins showed toxicity with an LC50 of 56.3 μg g−1. Therefore, the investigated combinational effect of BLB250 delta-endotoxins and R. tingitanus hexane extract proved significant synergistic effect against S. littoralis larvae. The GC-MS analysis of R. tingitanus hexane extract showed the richness of this extract in phytosterols such as β and γ-sitosterol (48.91%), campesterol (6.43%), and β-amyrin (8.92%) which are known for their insecticidal activity. This novel finding highlights the potential use of this combination against insect pests to prevent the appearance of resistance problems.


2015 ◽  
Vol 61 ◽  
pp. 102-107 ◽  
Author(s):  
Charles Adarkwah ◽  
George Nyarko ◽  
Nelson Opoku ◽  
Benjamin K. Badii ◽  
Isaac K. Addai ◽  
...  

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