Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Authors have evaluated herbicides for chemical control of the invasive tree Ailanthus altissima in Collserola Conservation Park of Barcelona. Very interesting work. 

Authors have evaluated different herbicides (Silvanet, Starane 20, Tordon Star, Genozone zx, Register 25, Adengo, Racing, Sencor liquid, Challenge, Garlon GS), its application timing (summer/autumn) and application method (stem injection/cut stump/basal bark treatment).  But I am clueless why different rates V/V (%) of a.i. (as given in Table 1) were used? What was the basis of that? And, what is Rate (%) in Table 2? Please elaborate about these different rates in methodology section.

Figure 5 depicted 2-way interaction effects of herbicide a.i. and its method of application. Authors are requested to provide ANOVA for the clarity of the effects of different treatment combinations.

Kindly see the attached file for minor errors marked in the PDF.

Comments for author File: Comments.pdf

Author Response

See attached file

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Dear colleagues,

I have reviewed your manuscript “Chemical control of the invasive tree Ailanthus altissima” submitted for publication on Agriculture.

I think this is a relevant and interesting study, given the various harms caused by the presence of this species and the difficulties in controlling it.

The study is well-planned and conducted and its findings provide landscape and park managers with relevant information about solutions for chemical control of this species. I have particularly appreciated the approach of monitoring control efficacy for several years after treatments since obtaining lasting control is a key issue when managing A. altissima.

I have some comments and suggestions to the text, I hope you will find them useful.

-Line 44 and throughout the text. When a scientific name is mentioned for the first time in a text, I recommend to include also the authority as done for A. altissima at Line 31

-Line 136 “Control trees (untreated plants)..” I would remove the term “untreated plants” since control plants for the cut stump injection were actually cut at 4 cm above ground level.

-Table 1: I would suggest including in this Table the HRAC Group classification for the several herbicide tested. This would enable even readers that are not herbicide experts to notice the variability in the Mode Of Action across the tested active ingredients.

-Lines 150-151 and throughout the text: “three active ingredients” I would rather use the term “three herbicides” because two treatments were actually mixtures of active ingredients. I would make this change throughout the text and particularly for section 2.3.3 and 3.3 titles (“Active ingredient efficacy”) because when a mixture of two or more active ingredients is applied, evaluating the specific efficacy of the single a.i. is often challenging.

-Lines 166-169: “The efficacy of the herbicides was evaluated in all experiments…”. I have a doubt about this point: were also data from summer application considered for this analysis? This could be a confounding factor since only three herbicides were applied in summer, as stated at Line 151, so the overall efficacy of those three treatments would be affected also by the application moment while this would not occour for the other herbicides. Considering only data from autumn application would be more appropriate and maybe the Authors did it, as Lines 180-181 (“According to these results and the literature, all subsequent experiments and data analysis were conducted with herbicides applied in autumn”) seem to suggest, but I recommend to clearly state it in the M&M.

-Lines 196-198 “it must be highlighted… showed no efficacy.” Metribuzin stem injection actually caused mortality in 80% of treated plants, so it definitely showed some efficacy, even if not optimal. Please rewrite this sentence.

-Lines 241-255 “There were certain herbicides..” I would suggest to remove this section since results described here originated from preliminary, non-repeated trials that were not described in the M&M section.

-Discussion: This section is straight-forward and clear, the findings of the present study have been appropriately compared with the existing literature. Maybe this section could be enriched by including a part about the environmental impact of the different herbicides tested in this study. As the Authors clearly stated in the Introduction (lines76-86), the selection of herbicides for controlling invasive species in non-cropped areas should not consider only their control efficacy in order to avoid unwanted negative effects on non-target species and the environment.

-Figures: I would suggest to modify the colours selected for the different treatment bars to increase the contrast among them. Figure 3 in particular would be rather problematic for colour-blind readers.

Author Response

See comments in the attached file

Author Response File: Author Response.docx