The Octopamine Receptor Is a Possible Target for Eugenol-Induced Hyperactivity in the Blood-Sucking Bug Triatoma infestans (Hemiptera: Reduviidae)

Novel Approach for a Controlled Delivery of Essential Oils during Long-Term Maize Storage: Clove Bud and Pennyroyal Oils Efficacy to Control Sitophilus zeamais, Reducing Grain Damage and Post-Harvest Losses

Maize grains represent a significant contribution for assuring food safety all over the globe. Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), also known as the maize weevil, is one of the most destructive pests in stored maize, causing qualitative and quantitative losses. To control S. zeamais populations in maize storage sites, synthetical chemical insecticides are applied. However, these are often used wastefully, have environmental implications, and can induce the development of resistant populations. In this work, the insecticidal and grain protecting efficacy of an innovative macro-capsule delivery device, loaded with essential oils from Clove bud and Pennyroyal, as well as their combined solutions, was tested against naturally S. zeamais-infested maize grains. The blend of both compounds incorporated in a controlled release device reduced losses by more than 45% over a long storage period of twenty weeks, diminishing the survivability of maize weevils by over 90%. The usage of the blend at a concentration of 370 μL⋅Lair-1 with an antioxidant showed the best results, however, by halving the concentration (185 μL⋅Lair-1), a significant control of S. zeamais populations was still achieved.

Alpha-Phellandrene and Alpha-Phellandrene-Rich Essential Oils: A Systematic Review of Biological Activities, Pharmaceutical and Food Applications

Alpha-phellandrene is a very common cyclic monoterpene found in several EOs, which shows extensive biological activities. Therefore, the main focus of the present systematic review was to provide a comprehensive and critical analysis of the state of the art regarding its biological activities and pharmaceutical and food applications. In addition, the study identified essential oils rich in alpha-phellandrene and summarized their main biological activities as a preliminary screening to encourage subsequent studies on their single components. With this review, we selected and critically analyzed 99 papers, using the following bibliographic databases: PubMed, SciELO, Wiley and WOS, on 8 July 2022. Data were independently extracted by four authors of this work, selecting those studies which reported the keyword "alpha-phellandrene" in the title and/or the abstract, and avoiding those in which there was not a clear correlation between the molecule and its biological activities and/or a specific concentration from its source. Duplication data were removed in the final article. Many essential oils have significant amounts of alpha-phellandrene, and the species Anethum graveolens and Foeniculum vulgare are frequently cited. Some studies on the above-mentioned species show high alpha-phellandrene amounts up to 82.1%. There were 12 studies on alpha-phellandrene as a pure molecule showed promising biological functions, including antitumoral, antinociceptive, larvicidal and insecticidal activities. There were 87 research works on EOs rich in alpha-phellandrene, which were summarized with a focus on additional data concerning potential biological activities. We believe this data is a useful starting point to start new research on the pure molecule, and, in particular, to distinguish between the synergistic effects of the different components of the OEs and those due to alpha-phellandrene itself. Toxicological data are still lacking, requiring further investigation on the threshold values to distinguish the boundary between beneficial and toxic effects, i.e., mutagenic, carcinogenic and allergenic. All these findings offer inspiration for potential applications of alpha-phellandrene as a new biopesticide, antimicrobial and antitumoral agent. In particular, we believe our work is of interest as a starting point for further studies on the food application of alpha-phellandrene.

Preference and effect of gustatory sense on sugar-feeding of fire ants

BACKGROUND

The red imported fire ant is one of the notorious species of ants all over the world. Sugar is one of the most important components of food and necessary for the survival of ants. Because more than 70% food of fire ants is honeydew produced by Homopteran insects such as aphids and scales.

METHODOLOGY

It is well known that beetles, flies, and honey bees can recognize the sugar taste through their legs and antennae, but in the case of fire ants, no records regarding gustatory sense were published. In the current study, considering the importance of sugar bait, we investigated the gustatory sense of the fire ant workers to sucrose via behavioral sequence and gustatory behavior. First, the feeding sequence (ethogram) of the fire ant workers on most preferred sugar (sucrose) solution was observed and categorized. Secondly, the gustatory behavior of treated fire ant workers (without flagellum and foreleg tarsi treated with HCL solution) was observed on the sucrose solution. In addition, using scanning electron microscopy (SEM) techniques, we identified the possible porous sensilla types on antenna flagellum and foreleg tarsi of fire ant workers.

RESULTS

Based on the results of feeding sequence, foreleg tarsi of workers were the main body appendages in the detection of the sucrose droplet as compared to antennae flagellum and palps. Feeding time of treated workers with HCL solution was significantly decreased on sucrose solution as compared to those workers having no flagellum. While both types of treated workers have less feeding time in comparison to normal workers. Based on the results of feeding sequence analysis and feeding time, it is indicating that the foreleg tarsi of workers play a more important role in the detection of sucrose solution as compared to antennae flagellum. Based on the SEM results, sensilla chaetic, trichoid II, and basiconic I and II have a clear pore at their tip. This study provides a substantial basis for elucidating the gustatory function of antennal and tarsal sensilla on appendages of fire ant workers to sugars and further baits improvement for the management of fire ants.

Plant-Derived Pesticides as an Alternative to Pest Management and Sustainable Agricultural Production: Prospects, Applications and Challenges

Pests and diseases are responsible for most of the losses related to agricultural crops, either in the field or in storage. Moreover, due to indiscriminate use of synthetic pesticides over the years, several issues have come along, such as pest resistance and contamination of important planet sources, such as water, air and soil. Therefore, in order to improve efficiency of crop production and reduce food crisis in a sustainable manner, while preserving consumer's health, plant-derived pesticides may be a green alternative to synthetic ones. They are cheap, biodegradable, ecofriendly and act by several mechanisms of action in a more specific way, suggesting that they are less of a hazard to humans and the environment. Natural plant products with bioactivity toward insects include several classes of molecules, for example: terpenes, flavonoids, alkaloids, polyphenols, cyanogenic glucosides, quinones, amides, aldehydes, thiophenes, amino acids, saccharides and polyketides (which is not an exhaustive list of insecticidal substances). In general, those compounds have important ecological activities in nature, such as: antifeedant, attractant, nematicide, fungicide, repellent, insecticide, insect growth regulator and allelopathic agents, acting as a promising source for novel pest control agents or biopesticides. However, several factors appear to limit their commercialization. In this critical review, a compilation of plant-derived metabolites, along with their corresponding toxicology and mechanisms of action, will be approached, as well as the different strategies developed in order to meet the required commercial standards through more efficient methods.