# Are Mycopesticides the Future of Locust Control?

Michel Lecoq, Arianne J Cease

► To cite this version:

Michel Lecoq, Arianne J Cease. Are Mycopesticides the Future of Locust Control?. Agronomy, 2022, 12 (10), pp.2344. 10.3390/agronomy12102344. hal-03965301

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Editorial

# Are Mycopesticides the Future of Locust Control?

Michel Lecoq <fnref n="1" />,* and Arianne J. Cease <fnref n="2" />

Locusts are a very serious problem for agriculture and for the livelihoods of populations around the world. Many lessons have been learned from decades of controlling these pests [1]. After the intensive use of chemical insecticides, new perspectives that are more respectful of people and the environment have emerged over the last twenty years. Protozoa, such as *Nosema locustae*, have been used and have many benefits; however, some limitations still need to be overcome [2]. Currently, entomopathogenic fungi are the most promising alternative, at least partially, to traditional chemical insecticides. The article from Wakil et al. [3] in this Special Issue dedicated to locust management is the first field study to test the efficacy of four different entomopathogenic fungal formulations together—*Metarhizium acridum* (Green Muscle® and Green Guard®), *Metarhizium anisopliae*, and *Beauveria bassiana*—against nymphs and adults of the desert locust *Schistocerca gregaria*. The study shows that all of these formulations have the potential to control locusts under field conditions. In addition, there are sublethal effects on their reproductive ability and behavior, with reductions in diet consumption, frass production, and weight observed. The authors conclude that future research needs to explore the combination of fungus with other control agents—including chemical insecticides, microsporidia, and botanical extracts—as a means of integrated pest management of locusts in the field.

Chemical pesticides have many side effects, and these have been increasingly elucidated, including their impact on human health, the environment, nontarget organisms, and biodiversity [4]. They have been shown to contribute to insect decline worldwide [5]. In addressing this issue, the use of biopesticides as a possible important component of locust management programs is a most significant recent development [6]. The benefits of using biopesticides include specificity to locusts and grasshoppers and the preservation of natural enemies [7]. The credibility of biopesticides as part of locust management programs is increasingly recognized, and programs that have included biopesticides have found them invaluable for treating locusts and grasshoppers wherever they occur [8]. As restrictions on the use of chemical pesticides rightly increase, treatment programs in the future will need to ensure their effectiveness by including biopesticides and by putting mechanisms in place to facilitate their use. Research and development supported by governments and donors will be critical in providing pathways to navigate logistical challenges such as manufacturing, storing, applications, and environmental limitations, especially the low temperature range over which locust mycopesticides are effective. It seems that we are at a turning point in locust control and that substitutes to chemical insecticides—notably mycopesticides—will become increasingly important in the future, not only in prevention—as originally thought—but also in periods of invasion, as shown by the mycopesticide-based treatments carried out during the last desert locust invasion in 2019–2020 [9–11]. *Metarhizium anisopliae* has already been listed for some years as one of the few products recommended by the Locust Pesticide Referee Group of the FAO to control the desert locust and any other locust species [12].

**Author Contributions:** M.L. wrote the first draft of the manuscript; A.J.C. reviewed and edited. All authors have read and agreed to the published version of the manuscript.

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**Citation:** Lecoq, M.; Cease, A.J. Are Mycopesticides the Future of Locust Control? *Agronomy* **2022**, *12*, 2344.
https://doi.org/10.3390/agronomy12102344

Received: 15 July 2022
Accepted: 26 September 2022
Published: 28 September 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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**Copyright:** © 2022 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

<footnote n="1">¹ CIRAD, UMR CBGP, F-34398 Montpellier, France</footnote>

<footnote n="2">² School of Sustainability and School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA</footnote>

<footnote>* Correspondence: mlecoq34@gmail.com</footnote>
**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.

## References

1. Lecoq, M.; Cease, A. What Have We Learned after Millennia of Locust Invasions? *Agronomy* **2022**, *12*, 472. [CrossRef]

2. Zhang, L.; Lecoq, M. *Nosema locustae* (Protozoa, Microsporidia), a biological agent for locust and grasshopper control. *Agronomy* **2021**, *11*, 711. [CrossRef]

3. Wakil, W.; Ghazanfar, M.U.; Usman, M.; Hunter, D.; Shi, W. Fungal-Based Biopesticide Formulations to Control Nymphs and Adults of the Desert Locust, *Schistocerca gregaria* Forskål (Orthoptera: Acrididae): A Laboratory and Field Cage Study. *Agronomy* **2022**, *12*, 1160. [CrossRef]

4. Zhang, L.; Lecoq, M.; Latchininsky, A.; Hunter, D. Locust and grasshopper management. *Annu. Rev. Entomol.* **2019**, *64*, 15–34. [CrossRef]

5. Sánchez-Bayo, F.; Wyckhuys, K.A.G. Worldwide decline of the entomofauna: A review of its drivers. *Biol. Conserv.* **2019**, *232*, 8–27. [CrossRef]

6. Lomer, C.J.; Bateman, R.P.; Johnson, D.L.; Langewald, J.; Thomas, M. Biological control of locusts and grasshoppers. *Annu. Rev. Entomol.* **2001**, *46*, 667–701. [CrossRef] [PubMed]

7. Zhang, L.; Hunter, D.M. Laboratory and field trials of Green Guard® Metarhizium anisopliae var. acridum (Deuteromycotina: Hyphomycetes) against the oriental migratory locust (*Locusta migratoria manilensis*) (Orthoptera: Acrididae) in China. *J. Orthoptera Res.* **2005**, *14*, 27–30. [CrossRef]

8. Hunter, D.M. Credibility of an IPM approach for locust and grasshopper control: The Australian example. *J. Orthoptera Res.* **2010**, *19*, 133–137. [CrossRef]

9. FAO. *Desert Locust Bulletin*, Nos. 484–495; Food and Agriculture Organization of the United Nations: Rome, Italy, 2019. Available online: https://www.fao.org/ag/locusts/en/archives/archive/2521/2570/index.html (accessed on 12 July 2022).

10. FAO. *Desert Locust Bulletin*, Nos. 496–507; Food and Agriculture Organization of the United Nations: Rome, Italy, 2020. Available online: https://www.fao.org/ag/locusts/en/archives/archive/2521/2618/index.html (accessed on 12 July 2022).

11. CABI. Green Muscle Providing Strength against Devastating Locusts in the Horn of Africa. 2020. Available online: https://www.cabi.org/news-article/green-muscle-providing-strength-against-devastating-locusts-in-the-horn-of-africa/ (accessed on 12 July 2022).

12. FAO. *Evaluation of Field Trials Data on the Efficacy and Selectivity of Insecticides on Locusts and Grasshoppers*; Report to FAO by the Locust Pesticide Referee Group, Eleventh Meeting (Virtual); Food and Agriculture Organization of the United Nations: Rome, Italy, 2021. Available online: https://www.fao.org/ag/locusts/common/ecg/2614/en/PRG11.pdf (accessed on 12 July 2022).