Potential of the Bacillus thuringiensis Toxin Reservoir for the Control of Lobesia botrana (Lepidoptera: Tortricidae), a Major Pest of Grape Plants

Abstract

The potential of Bacillus thuringiensis Cry proteins to control the grape pest Lobesia botrana was explored by testing first-instar larvae with Cry proteins belonging to the Cry1, Cry2, and Cry9 groups selected for their documented activities against Lepidoptera. Cry9Ca, a toxin from B. thuringiensis, was the protein most toxic to L. botrana larvae, followed in decreasing order by Cry2Ab, Cry1Ab, Cry2Aa, and Cry1Ia7, with 50% lethal concentration values of 0.09, 0.1, 1.4, 3.2, and 8.5 g/ml of diet, respectively. In contrast, Cry1Fa and Cry1JA were not active at the assayed concentration (100 g/ml). In vitro binding and competition experiments showed that none of the toxins tested (Cry1Ia, Cry2Aa, Cry2Ab, and Cry9C) shared binding sites with Cry1Ab. We conclude that either Cry1Ia or Cry9C could be used in combination with Cry1Ab to control this pest, either as the active components of B. thuringiensis sprays or expressed together in transgenic plants.

The entomopathogenic fungus, Metarhizium anisopliae for the European grapevine moth, Lobesia botrana Den. & Schiff. (Lepidoptera: Tortricidae) and its effect to the phytopathogenic fungus, Botrytis cinerea

“…The majority of biological control studies on the vine moth have focused on the use of Bacillus thuringiensis (Roditakis 1986 andDe Escudero et al 2007). However, Cozzi et al (2013) tested 11 fungal strains belonging to Fusarium (3 strains), Beauveria (6 strains), Paecilomyces (1 strain), and Verticillium (1 strain) genera.…”

Specific Binding of Bacillus thuringiensis Cry2A Insecticidal Proteins to a Common Site in the Midgut of Helicoverpa Species

“…Based on all these results, we propose for these two Helicoverpa species a model with independent binding sites for Cry1A and Cry2A toxins. This model may be extended to other insect species for which heterologous-competition experiments have shown the absence of competition between Cry1A and Cry2A toxins (3,18,22,23,24,25,39). In these studies, it was reported that competition either did not occur or occurred only at very high concentrations of competitor, suggesting that in some cases, the binding sites of Cry1A toxins may function as low-affinity binding sites of Cry2A toxins and vice versa.…”

Toxicological Examinations Following Oral Administration of Bacillus thuringiensis var kurstaki Biological Insecticide in Wistar Rats

“…5 They target a limited spectrum of pest insects that contain specific physiological properties (i.e., gut pH and toxin receptor sites in the midgut) and eventually have low risk to non-target species than broad-spectrum insecticides. [6][7][8] Cry toxins are mostly found in B. thuringiensis strains that mediate their toxic effects on a target organism. 9 Following ingestion by larval insects, the crystals were solubilized in the midgut and subsequently activated by proteases.…”