Next Article in Journal
Hylotelephium spectabile, a New Host for Carnation Tortrix Moth (Cacoecimorpha pronubana) and Molecular Characterization in Greece
Previous Article in Journal
Lessons from Drosophila: Engineering Genetic Sexing Strains with Temperature-Sensitive Lethality for Sterile Insect Technique Applications
Previous Article in Special Issue
Plant Allelochemicals as Sources of Insecticides
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:

Special Issue: Natural Substances against Insect Pests: Assets and Liabilities

Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
Insects 2021, 12(3), 244;
Received: 9 March 2021 / Accepted: 11 March 2021 / Published: 15 March 2021
(This article belongs to the Special Issue Natural Substances against Insect Pests: Assets and Liabilities)
Many insect pests directly compete with humans for food, damaging several crops in the field and during the processing and storage. Every year, about 20% of the global production of agricultural goods is lost due to more than 20,000 species of harmful insects. Moreover, some parasites can act as vectors of viruses and microorganisms, both pathogenic to humans and other vertebrates. The control of those species is, therefore, a crucial focus for the medical, veterinary, and agro-food chain operators. Scientific evidence revealed that the massive and continuous use of synthetic pesticides results in an accumulation of residues in the environment (causing air, soil, and water pollution), and have neurotoxic, carcinogenic, teratogenic, and mutagenic effects on human and non-target animals. Furthermore, the insurgence of resistance to the more commonly used chemicals in repeatedly treated pests is thoroughly stated in a multitude of scientific publications. Despite all the drawbacks reported, insect pest control still mainly relies on synthetic insecticides. Since the 1980s, research on natural products, also known as biopesticides, has highlighted their numerous helpful effects against insect pests. To fully understand and exploit the potential of natural substances, though, more improvement in the knowledge of their vast and various bioactivities is essential. Biopesticides comprise a broad group of different materials, which includes botanical products (e.g., volatile and fixed oils, vegetal extracts, hydrolates), inert dust (e.g., diatomaceous earth, granite dust, kaolin), as well as microorganisms (entomopathogenic bacteria, fungi). Because of their natural origin, biopesticides are supposed to have fewer side effects than synthetic pesticides, although they are not free from intrinsic limits. This “Natural Substances against Insect Pests: Assets and Liabilities” Special Issue (SI) addresses current basic and applied research on the isolation, chemical characterization, biochemistry, bioactivity, mode of action, benefits, and risks related to the use of natural substances as insecticides.
In detail, this SI includes studies on the bioactivities of some essential oils, such as Origanum vulgare [1], Citrus reticulata, Melaleuca alternifolia [2], Mentha arvensis [3], Cymbopogon citratus, C. winterianus, Eucalyptus citriodora, and E. camaldulensis [4]. These essential oils have been tested as insecticides and/or repellents against different Diptera species, from the pathogens carrying blowfly Calliphora vomitoria [1] and the mosquito Aedes aegypti [3,4] to the fruit fly Drosophila suzukii [2], demonstrating broad efficacy. One of the latest trends and challenges in the bioinsecticides field is the use of plant extracts obtained by the maceration of vegetal organs in a variety of organic or aqueous solvents. In this SI, the bioactivities of Ajuga iva [5], Ludwigia tomentosa, L. longifolia [6], Sophora alopecuroides [7], Psiadia penninervia, Salvia officinalis, Ochradenus baccatus, Pulicaria crispa, and Euryops arabicus [8] extracts have been evaluated. The target pests were two harmful Lepidoptera, the cotton leafworm Spodoptera littoralis [5] and the diamondback moth Plutella xylostella [6], the mosquito Aedes albopictus [7], the bean aphid Aphis craccivora, and its predator, the Neuroptera Chrysoperla carnea [8]. Vegetal extracts can act as insecticides, antifeedants, and, in some cases, as ecdysteroid. This latter mode of action interferes with the morphological and physiological transformations of the offspring while performing a certain selectivity towards entomophagous insects [8]. The main components of the extracts (e.g., alkaloids, flavonoids, saponins, tannins), not just the whole mixtures, can show a strong insecticidal effect, mostly depending on the route of administration. The production of natural-based products in nanoemulsion formulations, thanks to innovative nanotechnologies, could solve the miscibility and stability problems of the apolar compounds. This goal becomes particularly useful when related to mosquito larvae control in watery breeding sites [9]. The use of dusts, such as granite rock [10] and sulphur dust [11], against herbivorous pests could be exploited on some horticultural and ornamental crops and in vineyards within the integrated pest management context.
The SI also comprises two reviews: one on the bioactivity of vegetal extracts of Tephrosia species against stored product pests [12], and one regarding allelochemicals, the secondary metabolites produced by plants which are promising for crop protection against numerous harmful insects, thanks to their toxicity [13].
Last but not least, the SI contains a meta-analysis concerning 74 years of scientific literature, surveying over 2500 papers on botanical insecticides published between 1945 and 2019. This paper gives us a 360° view of the research in the bioinsecticides field, without neglecting the effects on non-target species, sub-lethal effects, and knowledge gaps [14].
In conclusion, this “Natural Substances against Insect Pests: Assets and Liabilities” Special Issue offers innovative empirical results and starting points to unravel the bioinsecticides’ complex bioactivity and role in the ecosystem.
I am very grateful to all the contributing authors, all the reviewers involved, and the editorial staff for their invaluable help in the assembly and editing of this very Special Issue.


This research received no external funding.

Institutional Review Board Statement

Not applicable.

Conflicts of Interest

The author declares no conflict of interest.


  1. Bedini, S.; Farina, P.; Napoli, E.; Flamini, G.; Ascrizzi, R.; Verzera, A.; Conti, B.; Zappalà, L. Bioactivity of Different Chemotypes of Oregano Essential Oil against the Blowfly Calliphora vomitoria Vector of Foodborne Pathogens. Insects 2021, 12, 52. [Google Scholar] [CrossRef] [PubMed]
  2. Bedini, S.; Cosci, F.; Tani, C.; Pierattini, E.C.; Venturi, F.; Lucchi, A.; Ioriatti, C.; Ascrizzi, R.; Flamini, G.; Ferroni, G.; et al. Essential Oils as Post-Harvest Crop Protectants against the Fruit Fly Drosophila suzukii: Bioactivity and Organoleptic Profile. Insects 2020, 11, 508. [Google Scholar] [CrossRef] [PubMed]
  3. Manh, H.D.; Tuyet, O.T. Larvicidal and Repellent Activity of Mentha arvensis L. Essential Oil against Aedes aegypti. Insects 2020, 11, 198. [Google Scholar] [CrossRef] [PubMed][Green Version]
  4. Manh, H.D.; Hue, D.T.; Hieu, N.T.T.; Tuyen, D.T.T.; Tuyet, O.T. The Mosquito Larvicidal Activity of Essential Oils from Cymbopogon and Eucalyptus Species in Vietnam. Insects 2020, 11, 128. [Google Scholar] [CrossRef] [PubMed][Green Version]
  5. Taha-Salaime, L.; Lebedev, G.; Abo-Nassar, J.; Marzouk, S.; Inbar, M.; Ghanim, M.; Aly, R. Activity of Ajuga iva Extracts Against the African Cotton Leafworm Spodoptera littoralis (Lepidoptera: Plutellidae). Insects 2020, 11, 726. [Google Scholar] [CrossRef] [PubMed]
  6. Ferreira, E.A.; de Souza, S.A.; Domingues, A.; Da Silva, M.M.M.; Padial, I.M.P.M.; de Carvalho, E.M.; Cardoso, C.A.L.; da Silva, S.V.; Mussury, R.M. Phytochemical Screening and Bioactivity of Ludwigia spp. in the Control of Plutella xylostella (Lepidoptera: Plutellidae). Insects 2020, 11, 596. [Google Scholar] [CrossRef] [PubMed]
  7. Shoukat, R.F.; Shakeel, M.; Rizvi, S.A.H.; Zafar, J.; Zhang, Y.; Freed, S.; Xu, X.; Jin, F. Larvicidal, Ovicidal, Synergistic, and Repellent Activities of Sophora alopecuroides and Its Dominant Constituents Against Aedes albopictus. Insects 2020, 11, 246. [Google Scholar] [CrossRef] [PubMed][Green Version]
  8. Sayed, S.M.; Alotaibi, S.S.; Gaber, N.; Elarrnaouty, S.-A. Evaluation of Five Medicinal Plant Extracts on Aphis craccivora (Hemiptera: Aphididae) and Its Predator, Chrysoperla carnea (Neuroptera: Chrysopidae) under Laboratory Conditions. Insects 2020, 11, 398. [Google Scholar] [CrossRef] [PubMed]
  9. Theochari, I.; Giatropoulos, A.; Papadimitriou, V.; Karras, V.; Balatsos, G.; Papachristos, D.; Michaelakis, A. Physicochemical Characteristics of Four Limonene-Based Nanoemulsions and Their Larvicidal Properties against Two Mosquito Species, Aedes albopictus and Culex pipiens molestus. Insects 2020, 11, 740. [Google Scholar] [CrossRef] [PubMed]
  10. Faraone, N.; Hillier, N.K. Preliminary Evaluation of a Granite Rock Dust Product for Pest Herbivore Management in Field Conditions. Insects 2020, 11, 877. [Google Scholar] [CrossRef] [PubMed]
  11. Tacoli, F.; Cargnus, E.; Zandigiacomo, P.; Pavan, F. Side Effects of Sulfur Dust on the European Grapevine Moth Lobesia botrana and the Predatory Mite Kampimodromus aberrans in Vineyards. Insects 2020, 11, 825. [Google Scholar] [CrossRef] [PubMed]
  12. Zhang, P.; Qin, D.; Chen, J.; Zhang, Z. Plants in the Genus Tephrosia: Valuable Resources for Botanical Insecticides. Insects 2020, 11, 721. [Google Scholar] [CrossRef] [PubMed]
  13. Tlak Gajger, I.; Dar, S.A. Plant Allelochemicals as Sources of Insecticides. Insects 2021, 12, 189. [Google Scholar] [CrossRef] [PubMed]
  14. Turchen, L.M.; Cosme-Júnior, L.; Guedes, R.N.C. Plant-Derived Insecticides Under Meta-Analyses: Status, Biases, and Knowledge Gaps. Insects 2020, 11, 532. [Google Scholar] [CrossRef] [PubMed]
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Conti, B. Special Issue: Natural Substances against Insect Pests: Assets and Liabilities. Insects 2021, 12, 244.

AMA Style

Conti B. Special Issue: Natural Substances against Insect Pests: Assets and Liabilities. Insects. 2021; 12(3):244.

Chicago/Turabian Style

Conti, Barbara. 2021. "Special Issue: Natural Substances against Insect Pests: Assets and Liabilities" Insects 12, no. 3: 244.

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop