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14 pages, 821 KiB

Open AccessArticle

Chemical Profiling, Sensory Qualities, and Bioactivities of Essential Oils Obtained from Aloysia citrodora and Bursera graveolens Ecuadorian Plants Against the Mosquito Aedes albopictus (Skuse) (Diptera: Culicidae)

by Prangthip Parichanon, Roberta Ascrizzi, Camilla Tani, Maria Cristina Echeverria, Sania Ortega Andrade, Hugo Paredes, Isabella Taglieri, Guido Flamini, Francesca Venturi and Barbara Conti

Insects 2025, 16(2), 202; https://doi.org/10.3390/insects16020202 - 12 Feb 2025

Viewed by 1013

Abstract

The mosquito Aedes albopictus is a vector of several harmful viruses, necessitating the development of safer and more sustainable repellents than DEET. This study evaluated the potential of plant-based EOs extracted via steam distillation from Aloysia citrodora and Bursera graveolens plants harvested in [...] Read more.

The mosquito Aedes albopictus is a vector of several harmful viruses, necessitating the development of safer and more sustainable repellents than DEET. This study evaluated the potential of plant-based EOs extracted via steam distillation from Aloysia citrodora and Bursera graveolens plants harvested in Ecuador. A. citrodora EO exhibited a high sensory pleasantness with a citral-like aroma, while B. graveolens EO had lower sensory appeal due to off-flavors. At 200 µL L⁻¹, B. graveolens EO demonstrated strong ovideterrent activity, reducing egg laying by 64%, whereas A. citrodora EO displayed the highest larvicidal activity with an LC₅₀ value of 88.54 µL L⁻¹. Both EOs, applied at 0.20 µL cm⁻² on human skin, provided comparable repellency for over 45 min. The RD₅₀ values were 0.104 µL cm⁻² for A. citrodora EO and 0.136 µL cm⁻² for B. graveolens EO. When compared to DEET at 0.04 µL cm⁻², no significant differences in repellency were observed within the first 15 min post-application. These findings suggest that both EOs are effective alternatives to synthetic repellents, and A. citrodora EO emerges as a promising candidate due to its superior sensory attributes and larvicidal activity. Full article

(This article belongs to the Special Issue New Formulations of Natural Substances against Insect Pests)

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25 pages, 5170 KiB

Open AccessArticle

Ecological Repellent Preparations Based on Natural Polymers with the Addition of Essential Oils Acting on Ticks

by Monika Owczarek, Maria Wiśniewska-Wrona, Katarzyna Bartosik, Alicja Buczek, Monika Sikora, Klaudia Piekarska, Piotr Cichacz, Patryk Śniarowski, Zdzisława Mrozińska, Marcin H. Kudzin, Karolina Gzyra-Jagieła and Jagoda Jóźwik-Pruska

Insects 2024, 15(12), 931; https://doi.org/10.3390/insects15120931 - 27 Nov 2024

Viewed by 1095

Abstract

Background: Ticks (Acari: Ixodida) pose a serious medical and veterinary threat as vectors of tick-borne pathogens. The wide variety of tick repellents available on the market primarily consist of synthetic preparations that may disrupt the ecological balance and accumulate in the environment, leading [...] Read more.

Background: Ticks (Acari: Ixodida) pose a serious medical and veterinary threat as vectors of tick-borne pathogens. The wide variety of tick repellents available on the market primarily consist of synthetic preparations that may disrupt the ecological balance and accumulate in the environment, leading to harmful effects on humans and animals. The aim of the study was to develop an ecological preparation based on natural raw materials (biopolymers) with the addition of a mixture of essential oils that act as tick repellents. Methods: The preparations were acquired through the emulsification method, specifically the oil-in-water emulsion technique. The assessment encompassed an analysis of their physicochemical properties, including centrifugal and thermal stability, dynamic viscosity, wetting angle, and conductivity. Additionally, their biodegradation and ecotoxicity profiles were evaluated, as well as their impact on tick behavior. Results: The preparations exhibited stability, rapid biodegradation, and absence of ecotoxicity. Additionally, they had repellent properties against the two tested species of ticks (Ixodes ricinus and Dermacentor reticulatus). Conclusions: Emulsion formulations comprising natural ingredients have significant research potential for combating ticks, thus mitigating the risk of tick-borne diseases in both human and animal populations. Full article

(This article belongs to the Special Issue New Formulations of Natural Substances against Insect Pests)

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19 pages, 3262 KiB

Open AccessArticle

Evaluating the Efficacy of Plant Extracts in Managing the Bruchid Beetle, Callosobruchus maculatus (Coleoptera: Bruchidae)

by Rasheed Akbar, Brekhna Faheem, Tariq Aziz, Amjad Ali, Asmat Ullah, Imtiaz Ali Khan and Jianfan Sun

Insects 2024, 15(9), 691; https://doi.org/10.3390/insects15090691 - 12 Sep 2024

Cited by 8 | Viewed by 2037

Abstract

An estimated 2000 plant species have been employed for pest control worldwide. The use of these botanical derivatives is thought to be one of the most cost-effective and sustainable options for pest management in stored grain. The present study was designed to assess [...] Read more.

An estimated 2000 plant species have been employed for pest control worldwide. The use of these botanical derivatives is thought to be one of the most cost-effective and sustainable options for pest management in stored grain. The present study was designed to assess the efficacy of five plant extracts viz; Nicotiana tabacum L., Nicotiana rustica L., Azadirachta indica A. Juss., Thuja orientalis L., and Melia azedarach L. against Callosobruchus maculatus L. Plant species extracts were applied at six different concentrations, i.e., 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0% in four replications. The phytochemical analyses of ethanolic extracts of five plant species showed variable amounts of phytochemicals i.e., alkaloids, flavonoids, saponins, diterpenes, phytosterol, and phenols. Total phenolic and flavonoid compounds were also observed. The efficacy of A. indica was highest, characterized by the lowest infestation rate (16.65%), host seed weight loss (7.85%), mean oviposition (84.54), and adult emergence (58.40%). In contrast, T. orientalis was found to be the least effective against C. maculatus, with the highest infestation rate of 25.60%, host seed weight loss of 26.73%, mean oviposition of 117.17, and adult emergence rate of 82.01%. Probit analysis was performed by estimating LC₅₀ and LC₉₀. The toxicity percentages of N. tabacum (LC₅₀ = 0.69%, LC₉₀ = 14.59%), N. rustica (LC₅₀ = 0.98%, LC₉₀ = 22.06%), and A. indica (LC₅₀ = 1.09%, LC₉₀ = 68.52%) were notable in terms of the lower LC₅₀ and LC₉₀ values after the 96-h exposure period against C. maculatus. Repellency was assessed by using the area preference and filter paper method. The repellency of C. maculatus on plant extracts increased with the increasing dose and time, such that it was the highest after 48 h. Likewise, at a 3% concentration, A. indica demonstrated 100.00% (Class-V) repellency followed by N. tabacum (96.00%, Class-V), N. rustica (74%, Class-IV), M. azedarach (70.00%, Class-IV), and T. orientalis (68.00%, Class-IV). Based on the findings of this study, we recommend integrating N. rustica, N. tabacum, A. indica, and M. azedarach for effective management of C. maculatus and highlight the potential of these plant species in the formulation of new biocidal agents. Full article

(This article belongs to the Special Issue New Formulations of Natural Substances against Insect Pests)

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20 pages, 1884 KiB

Open AccessArticle

Target Enzymes of Origanum majorana and Rosmarinus officinalis Essential Oils in Black Cutworm (Agrotis ipsilon): In Vitro and In Silico Studies

by Fatma S. Ahmed, Walid S. Helmy, Nawal Abdulaziz Alfuhaid and Moataz A. M. Moustafa

Insects 2024, 15(7), 483; https://doi.org/10.3390/insects15070483 - 28 Jun 2024

Cited by 7 | Viewed by 1316

Abstract

In this study, in vitro and in silico approaches were employed to assess the toxicity of marjoram (Origanum majorana) and rosemary (Rosmarinus officinalis) essential oils (EOs) to A. ipsilon larvae. The study determined the activities of ATPases in the [...] Read more.

In this study, in vitro and in silico approaches were employed to assess the toxicity of marjoram (Origanum majorana) and rosemary (Rosmarinus officinalis) essential oils (EOs) to A. ipsilon larvae. The study determined the activities of ATPases in the larvae after treatment with the LC₂₀ and LC₇₀ of each EO. α-esterase and glutathione-S-transferase (GST) activities were also determined after treatment with LC₁₀ and LC₃₀ of each EO. Furthermore, molecular docking was employed to determine the binding affinity of terpinene-4-ol and α-pinene, the major constituents of O. majorana, and R. officinalis EOs, respectively, compared to the co-crystallized ligand of α-esterase, diethyl hydrogen phosphate (DPF). Toxicity assays revealed that O. majorana EO was more toxic than R. officinalis EO to the A. ipsilon larvae at 96 h post-treatment. However, the LC₂₀ and LC₇₀ of the latter significantly inhibited the activity of the Na⁺-K⁺ pump at almost all intervals. The same concentrations significantly inhibited the Mg²⁺/Ca²⁺-ATPase and Ca²⁺ pump at 96 h post-treatment. In contrast, O. majorana EO showed a variable effect on the Na+-K+ pump across different time intervals. On the other hand, LC₁₀ and LC₃₀ of both EOs showed varied effects on α-esterase and GST over time. Molecular docking revealed energy scores of −4.51 and −4.29 kcal/mol for terpinene-4-ol and α-pinene, respectively, compared to a score of −4.67 for PDF. Our study demonstrated the toxicity of the tested EOs to A. ipsilon, suggesting their potential efficacy as insecticides. Full article

(This article belongs to the Special Issue New Formulations of Natural Substances against Insect Pests)

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16 pages, 2703 KiB

Open AccessArticle

Efficacy of Metarhizium anisopliae, Isolate ICIPE 7, against Anopheles arabiensis, Glossina fuscipes, and Rhipicephalus spp.

by Fedinand Ong’wen, Margaret Mendi Njoroge, Ulrike Fillinger, Heike Lutermann and Tullu Bukhari

Insects 2024, 15(6), 449; https://doi.org/10.3390/insects15060449 - 13 Jun 2024

Cited by 1 | Viewed by 1973

Abstract

Arthropod vectors are responsible for a multitude of human and animal diseases affecting poor communities in sub-Saharan Africa. Their control still relies on chemical agents, despite growing evidence of insecticide resistance and environmental health concerns. Biorational agents, such as the entomopathogenic fungus Metarhizium [...] Read more.

Arthropod vectors are responsible for a multitude of human and animal diseases affecting poor communities in sub-Saharan Africa. Their control still relies on chemical agents, despite growing evidence of insecticide resistance and environmental health concerns. Biorational agents, such as the entomopathogenic fungus Metarhizium anisopliae, might be an alternative for vector control. Recently, the M. anisopliae isolate ICIPE 7 has been developed into a commercial product in Kenya for control of ticks on cattle. We were interested in assessing the potential of controlling not only ticks but also disease-transmitting mosquitoes and tsetse flies using cattle as blood hosts, with the aim of developing a product for integrated vector management. Laboratory bioassays were carried out with M. anisopliae, isolate ICIPE 7 and isolate ICIPE 30, to compare efficacy against laboratory-reared Anopheles arabiensis. ICIPE 7 was further tested against wild Glossina fuscipes and Rhipicephalus spp. Dose–response tests were implemented, period of mosquito exposure was evaluated for effects on time to death, and the number of spores attached to exposed vectors was assessed. Exposure to 10⁹ spores/mL of ICIPE 7 for 10 min resulted in a similar mortality of An. arabiensis as exposure to ICIPE 30, albeit at a slower rate (12 vs. 8 days). The same ICIPE 7 concentration also resulted in mortalities of tsetse flies (LT₅₀: 16 days), tick nymphs (LT₅₀: 11 days), and adult ticks (LT₅₀: 20 days). Mosquito mortality was dose-dependent, with decreasing LT₅₀ of 8 days at a concentration of 10⁶ spores/mL to 6 days at 10¹⁰ spores/mL. Exposure period did not modulate the outcome, 1 min of exposure still resulted in mortality, and spore attachment to vectors was dose-dependent. The laboratory bioassays confirmed that ICIPE 7 has the potential to infect and cause mortality to the three exposed arthropods, though at slower rate, thus requiring further validation under field conditions. Full article

(This article belongs to the Special Issue New Formulations of Natural Substances against Insect Pests)

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11 pages, 517 KiB

Open AccessArticle

Ethyl Formate Fumigation against Pineapple Mealybug, Dysmicoccus brevipes, a Quarantine Insect Pest of Pineapples

by Tae Hyung Kwon, Dong-Bin Kim, Bongsu Kim, Joanna Bloese, Byung-Ho Lee and Dong H. Cha

Insects 2024, 15(1), 25; https://doi.org/10.3390/insects15010025 - 2 Jan 2024

Cited by 1 | Viewed by 2284

Abstract

Pineapple mealybug, Dysmicoccus brevipes (Hemiptera: Pseudococcidae), is a significant pest in pineapple production and a key trade barrier. We explored the potential use of ethyl formate (EF) as a methyl bromide alternative for the postharvest fumigation of D. brevipes in imported pineapples. When [...] Read more.

Pineapple mealybug, Dysmicoccus brevipes (Hemiptera: Pseudococcidae), is a significant pest in pineapple production and a key trade barrier. We explored the potential use of ethyl formate (EF) as a methyl bromide alternative for the postharvest fumigation of D. brevipes in imported pineapples. When treated at 8 °C for 4 h, EF fumigation was effective against D. brevipes with LCt_99, the lethal concentration × time product of EF necessary to achieve 99% mortality of D. brevipes nymphs and adults at 64.2 and 134.8 g h/m³, respectively. Sorption trials conducted with 70 g/m³ EF for 4 h at 8 °C using 7.5, 15 and 30% pineapple loading ratios (w/v) indicated that loading ratio lower than 30% is necessary to achieve the LCt₉₉ values required to control D. brevipes. In a scaled up trial using 1 m³ chamber, EF fumigation with 70 g/m³ for 4 h at 8 °C with 20% pineapple loading ratio (w/v) resulted in a complete control of D. brevipes treated. There were no significant differences in hue values, sugar contents, firmness, and weight loss between EF-treated and untreated pineapples. Our results suggest that EF is a promising alternative to methyl bromide fumigation for the postharvest phytosanitary disinfection of D. brevipes in pineapples. Full article

(This article belongs to the Special Issue New Formulations of Natural Substances against Insect Pests)

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17 pages, 2179 KiB

Open AccessArticle

In Vivo Bioassay of the Repellent Activity of Caraway Essential Oil against Green Peach Aphid

by Jessica Girardi, Kristīne Berķe-Ļubinska, Ieva Mežaka, Ilva Nakurte, Gundars Skudriņš and Laura Pastare

Insects 2023, 14(11), 876; https://doi.org/10.3390/insects14110876 - 14 Nov 2023

Cited by 4 | Viewed by 2530

Abstract

An in vivo dual choice bioassay with white cabbage as a host plant was used to determine the repellent effect of three different accessions of caraway (Carum carvi L.) essential oils (EOs) against the green peach aphid Myzus persicae (Sulzer). The dominant [...] Read more.

An in vivo dual choice bioassay with white cabbage as a host plant was used to determine the repellent effect of three different accessions of caraway (Carum carvi L.) essential oils (EOs) against the green peach aphid Myzus persicae (Sulzer). The dominant components of the EO were D-Carvone (47.3–74.4%) and D-limonene (25.2–51.9%), which accounted for 99.2–99.5% of the EOs determined by GC/MS. The EO with the highest D-limonene content (51.9%) showed the highest repellence (Repellency Index (RI) = +41%), which was stable up to 330 min. The incorporation of several surfactants with different hydrophilic-lipophilic balance values (from 12.4 to 16.7) with caraway EO caused a general inhibition of the repellent effect during the testing period (RI from +41% to −19%). Overall, the findings indicate that caraway EO could be used as a green peach aphid repellent, but more work is needed to formulate the EO into a ready-to-use product. Full article

(This article belongs to the Special Issue New Formulations of Natural Substances against Insect Pests)

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Review

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16 pages, 1161 KiB

Open AccessEditor’s ChoiceReview

Chitosan as a Control Tool for Insect Pest Management: A Review

by Linda Abenaim and Barbara Conti

Insects 2023, 14(12), 949; https://doi.org/10.3390/insects14120949 - 15 Dec 2023

Cited by 13 | Viewed by 4905

Abstract

Chitosan, a polysaccharide derived from the deacetylation of chitin, is a versatile and eco-friendly biopolymer with several applications. Chitosan is recognized for its biodegradability, biocompatibility, and non-toxicity, beyond its antimicrobial, antioxidant, and antitumoral activities. Thanks to its properties, chitosan is used in many [...] Read more.

Chitosan, a polysaccharide derived from the deacetylation of chitin, is a versatile and eco-friendly biopolymer with several applications. Chitosan is recognized for its biodegradability, biocompatibility, and non-toxicity, beyond its antimicrobial, antioxidant, and antitumoral activities. Thanks to its properties, chitosan is used in many fields including medicine, pharmacy, cosmetics, textile, nutrition, and agriculture. This review focuses on chitosan’s role as a tool in insect pest control, particularly for agriculture, foodstuff, and public health pests. Different formulations, including plain chitosan, chitosan coating, chitosan with nematodes, chitosan’s modifications, and chitosan nanoparticles, are explored. Biological assays using these formulations highlighted the use of chitosan–essential oil nanoparticles as an effective tool for pest control, due to their enhanced mobility and essential oils’ prolonged release over time. Chitosan’s derivatives with alkyl, benzyl, and acyl groups showed good activity against insect pests due to improved solubility and enhanced activity compared to plain chitosan. Thus, the purpose of this review is to provide the reader with updated information concerning the use and potential applications of chitosan formulations as pest control tools. Full article

(This article belongs to the Special Issue New Formulations of Natural Substances against Insect Pests)

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