Side effects of Bacillus thuringiensis var. kurstaki on the hymenopterous parasitic wasp Trichogramma chilonis

Abstract

Most of the detrimental effects of using conventional insecticides to control crop pests are now well identified and are nowadays major arguments for replacing such compounds by the use of biological control agents. In this respect, the bacterium Bacillus thuringiensis var. kurstaki and Trichogramma (Hymenoptera: Trichogrammatidae) parasitic wasp species are both effective against lepidopterous pests and can actually be used concomitantly. In this work, we studied the potential side effects of B. thuringiensis var. kurstaki on Trichogramma chilonis females. We first evidenced an acute toxicity of B. thuringiensis on T. chilonis. Then, after ingestion of B. thuringiensis at sublethal doses, we focused on life history traits of T. chilonis such as longevity, reproductive success and the time spent on host eggs patches. The reproductive success of T. chilonis was not modified by B. thuringiensis while a significant effect was observed on longevity and the time spent on host eggs patches. The physiological and ecological meanings of the results obtained are discussed.

Bacillus thuringiensis Bioinsecticides Induce Developmental Defects in Non-Target Drosophila melanogaster Larvae

“…Indeed, studies have highlighted that Cry toxins can delay the development and increase the mortality of trichopteran species whose larvae have an aquatic lifestyle [ 19 , 20 ]. Btk bioinsecticides are also acutely toxic against Trichogramma chilonis females, a tiny egg endoparasitoid hymenopteran used as a biocontrol agent in integrated pest management to control lepidopteran pests on crops [ 21 ] and delay the imago emergence of many Drosophila species [ 22 ]. In vertebrates, Grisolia and colleagues observed that the exposure of Danio rerio fry to different Btk Cry toxins induced lethality and developmental delay [ 23 ].…”

Biological parameters and thermal requirements of Trichogramma pretiosum reared on Helicoverpa armigera eggs

“…Due to the lack of studies on the integrated management of H. armigera, the main control method is represented by the use of chemical insecticides, which results in disadvantages because of the high use of toxic substances that are not very selective, showing slow environmental degradation and also potential to bioaccumulation and biomagnification. At the same time, these chemical pesticides can lead to serious consequences such as the target pest resistance, elimination of natural enemies, environmental contamination and risks to human health (Amichot et al, 2016).…”

Bacillus thuringiensisbioinsecticides induce developmental defects in non-targetDrosophila melanogasterlarvae

“…More recently, Amichot and colleagues have shown that Btk bioinsecticides are acutely toxic against Trichogramma chilonis females, a tiny egg endoparasitoid hymenopteran used as a biocontrol agent in integrated pest management (Amichot et al, 2016). On vertebrates, Grisolia and colleagues observed that the exposure of Danio rerio fry to different Btk Cry toxins induced lethality and developmental delay (Grisolia et al, 2009).…”