Highest degrees of host specificity even in the inundative biocontrol approach. Response to Cripps et al.

Abstract

Citation: Wolfgang Nentwig (2012) Highest degrees of host specificity even in the inundative biocontrol approach. Response to Cripps et al. NeoBiota 13: 41–42. doi: 10.3897/neobiota.13.3381 The response to the long letter, Cripps et al. (2012) wrote against Müller and Nentwig (Plant pathogens as biological agents of Cirsium arvense – an overestimated approach? NeoBiota 11:1–24, 2011) can be summarised in three points: (1) There are two approaches for biocontrol, classical biocontrol and inundative biocontrol. It is usually accepted that both differ in goals and requirements. In our literature review on the efficiency of various pathogens to control Cirsium arvense, we did not consequently mention for which approach which pathogen has been proposed since many articles we reviewed did not discuss this aspect. Moreover, there is a tendency to propose agents with insufficient target selec-tivity for the inundative method. In fact, both techniques do not represent discrete categories, but rather a continuum. (2) Nevertheless, Cripps et al. state that inundative biocontrol agents do not need to be specific. Instead of importing " new species " (they probably mean " alien species " and want to refer to classical biocontrol), they define inundative bio-control as usage of " already present, often cosmopolitan generalist microbial pathogens " . They recommend this application, call it safe and sustainable, but do not discuss why already present pathogen species shall be applied or why they are not effective. Moreover, this statement shows an astonishing lack of sensitivity to spreading species which are considered to be cosmopolitan, thus ignoring potential safety problems with non-targets.