Parasitism of different Trichogramma species and strains on Plutella xylostella L. on greenhouse cauliflower

Abstract

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the most important pest of cultivated Brassica worldwide, including those grown in greenhouses like cauliflower. In this article, we evaluate the potential of various species (and various strains of some species) of Trichogrammatidae (Hymenoptera: Chalcidoidea) to control this pest on cauliflower in greenhouse in France. We assessed the parasitism levels on P. xylostella of 17 Trichogrammatidae strains, belonging to 12 different species (2 indigenous strains from France), under greenhouse conditions. Parasitism levels for each of the Trichogrammatidae species and strains were determined on cauliflower leaves (Brassica oleracea botrytis L., Brassicaceae) infested with P. xylostella eggs. Nine strains parasitized 60% (or more) of the P. xylostella eggs. Compared to previous results in laboratory conditions, climatic conditions of the greenhouse did not influence parasitism levels. The presence of the cauliflower plants may have a positive effect on eight strains, a negative effect on four strains and no effect on five strains. Our study points out the importance of including the host plant of P. xylostella when conducting studies aiming to select the most efficient parasitoid against this pest.

Performance of four Trichogramma species (Hymenoptera: Trichogrammatidae) as biocontrol agents of Heliothis virescens (Lepidoptera: Noctuidae) under various temperature regimes

“…However, although our results on T. pretiosum showing highest parasitism rate at 25°C were similar to the findings by Maceda et al (2003) on E. kuehniella eggs, a strain of T. pretiosum (strain ''bonagota'') showed highest parasitism rates at lower temperatures of 18-22°C on the Brazilian apple leafroller ). Thus, variation in biological traits (such as parasitism at different temperatures) among strains could be important, as previously reported for other Trichogramma species (Smith 1996;Klug and Meyhöfer 2009;Pizzol et al 2010;Tabone et al 2010). The effects of temperature on parasitism rate seem to be driven by the temperature during testing rather than the rearing temperature.…”

“…Multiple abiotic and biotic factors can directly affect parasitoid efficiency (Mulatu et al 2006;Emana 2007;Desneux and Ramirez-Romero 2009;Rousse et al 2009) and therefore they should be considered and carefully studied. Difference in important biological traits related to Trichogramma species effectiveness can vary among strains of a same species (Klug and Meyhöfer 2009;Pizzol et al 2010;Tabone et al 2010). Further studies should document how various factors related to the cotton agro-ecosystem (e.g., how to combine parasitoids and pesticides in IPM programs?…”

“…Indeed, parasitoid effectiveness varies largely according to species (and even strains of one species) (Klug and Meyhöfer 2009;Tabone et al 2010) or climatic conditions (Smith 1996). Abiotic factors can affect multiple biological traits of these parasitoids (Scott et al 1997;Pratissoli et al 2005;Oliveira et al 2007;Bueno et al 2008), and temperature, in particular, influences development rate, parasitism rate, sex ratio and longevity (Hoffmann and Hewa-Kapuge 2000;Pizzol et al 2010).…”

Trichogramma chilonis Ishii: A potential biological control agent of Crocidolomia pavonana in Samoa

“…Thus, unraveling the ecological reasons for the success of T. chilonis against C. pavonana in Samoa will be intriguing and fundamental to any attempts to develop the parasitoid as a biological control agent. Different populations of T. chilonis are known to have different efficacies against P. xylostella (Tabone et al, 2010) and similar studies to compare the efficacy of the Samoan T.…”

Temperature-dependent differences in biological traits between two strains of Trichogramma cacoeciae (Hymenoptera: Trichogrammatidae)

“…Parasitoid effectiveness sometimes varies according to strains (Pizzol and Wajnberg 1994;Klug and Meyhöfer 2009;Tabone et al 2010) or climatic conditions (Smith 1996). Among Trichogramma species, Trichogramma cacoeciae Marchal is largely used as biological control agent against various pests and is a species spread worldwide (Pintureau 1997).…”