Correction: Lozano-Soria et al. Volatile Organic Compounds from Entomopathogenic and Nematophagous Fungi, Repel Banana Black Weevil (Cosmopolites sordidus). Insects 2020, 11, 509

In the original publication [...].


Figure Legend
In the original publication [1], there was a mistake in the legend for Figure 4.The correct name for compound C7 is 2-cyclohepten-1-one.The correct legend appears below.The authors state that the scientific conclusions are unaffected.This correction was approved by the Academic Editor.The original publication has also been updated.

Text Correction
There was an error in the original publication.One of the VOCs found in the volatilome of entomopathogenic and nematophagous fungi was 3-cyclohepten-1-one (also called C7 in the article).The olfactometric tests with banana weevil (Cosmopolites sordidus) were conducted instead with 2-cyclohepten-1-one.The reason being that this was the only isomer commercially available rather than 3-cyclohepten-1-one.
A correction has been made to Abstract.
A correction has been made to 2. Materials and Methods, 2.8.Fungal VOCs Repellency.
Of the VOCs identified using the fungal chromatograms, we tested the six pure substances commercially available for repellence against C. sordidus, except for 3-cyclohepten-1-one, because it was not commercially available.To replace 3-cyclohepten-1-one, we used 2-cyclohepten-1-one, the closest commercially available isomer.The substances were tested as pure compounds one by one and not in mixtures with each other.For the tests, in one arm of the olfactometer a piece of fresh corm/pseudocorm was placed, on the other arm 0.5 mL (C1, C2, C5, C6 and C7) or 0.5 g (C3 and C4) of the pure compounds were inoculated by placing them in a miracloth (Merck KGaA, Darmstadt, Germany) envelop (3.5 × 2.5 cm) with 2 g of silica gel (60A; 70-200 µ, Carlo Erba, Milan, Italy).The volume or weight of the compound was added directly to the silica gel.For the fresh garlic slices (local supermarket) and the colloidal sulphur (Sipcam Jardin S.L., Sipcam, Milan, Italy) 15.6 g of each substance was used.
A correction has been made to Section 4. Discussion.
Corrected paragraph: Bananas are essential for food security in tropical and subtropical countries, being one of the best-known, consumed and cultivated fruits [72,73].Cosmopolites sordidus is a major pest of bananas.It causes more crop destruction than any other arthropod pest in all banana producing countries [5].BW-resistant banana plants do not cover main commercial cultivars, making this pest a severe problem [74][75][76].
Biological control agents such as entomopathogenic fungi could be used for BW management [5,77].However, C. sordidus larvae and adults spend most of their life cycle within the banana plant, where it is hard to target them using EF conidia.Moreover, the adults move from plant to plant, hiding in the leaf litter, complicating the use of EF conidia.Lopes et al. [78] reported that C. sordidus adults are less sensitive to B. bassiana in auto-infection systems (mortality ranged between 21.7 and 1%) than other beetles, like Cylas formicarius (Fabricius, 1798) and Ips typographus (Linnaeus, 1758).
In this work, we take an alternative approach for BW biomanagement using fungal VOCs.BWs have efficient search mechanisms based on their antennae, specialized primary chemo and mechanoreceptors, which are crucial to ensure the survival and reproduction of BWs in the environment [13].
Fungi produce volatile compounds [34,35].Some of them act as attractants and/or repellents for insects and other invertebrates [42,[46][47][48][49][50][51][52].These compounds may alert the insect about possible partners, food, suitable places to lay their eggs or dangers that should be avoided.Therefore, any chemical that could interrupt and modify the behaviour of the BW and, in general, its searching ability for the host (Musa sp.) could serve as a tool for BW sustainable management.
We have isolated entomopathogenic fungi from banana crop soils in Tenerife (Canary Islands, Spain), where BW infestations are documented, looking for VOCs that are repellent to BW. Beauveria bassiana (1TS11) and M. robertsii (4TS04), both pathogenic to BW, were selected for VOC analysis from this survey.These fungi are common in agricultural fields [79] and banana crops [78].Since B. bassiana 203 produces VOCs repellent to R. ferrugineus [68], it was included in this study.Pochonia chlamydosporia 123, a nematophagous fungus closely related to M. anisopliae [20,21], with a large array of secondary metabolites [80] was also tested for VOC production.Genomic studies support that some Metarhizium species and P. chlamydosporia have a single ancestral joint [21].
These fungi produce a total of 97 VOCs.The VOC 3-cyclohepten-1-one, one of the main VOCs produced by all fungal strains [81], was not tested on C. sordidus because it was not commercially available.However, its isomer 2-cyclohepten-1-one (C7) reduced BW mobility most among the seven VOCs tested.Previous work found that stereoisomers and isomers can be equally repellent to insects, while other studies describe that insect repellence was different for various piperidine isomers.We do not know how 3-cyclohepten-1-one acts as a repellent, but the most similar isomer, 2-cyclohepten-1-one, repels BW.We decided to test 2-cyclohepten-1-one as a first approach to validate cycloheptenes as BW repellents.The synthesis of 3-cyclohepten-1-one in the laboratory is complex, expensive, and tedious (involving oxidation and ring closure).3-cyclohepten-1-one is also the most unstable cycloheptene isomer because it to isomerizes the double bond to form the more stable 2-cyclohepten-1-one (used in this study as C7).Therefore, 3-cyclohepten-1-one is unavailable in the quantities required for bioassays, let alone field trials.Electroantennography of experimentally synthesized 3-cyclohepten-1-one could, however, be performed in future studies.
A correction has been made to Section 5. Conclusions.