Sensory Quality of Essential Oils and Their Synergistic Effect with Diatomaceous Earth, for the Control of Stored Grain Insects

Abstract

Essential oils (EOs) have gained increasing interest as a low-toxic, eco-friendly alternative to synthetic repellents and insecticides against insect pests. However, they have scarce practical application in the protection of stored grain because of their limited efficacy and their interference with the organoleptic properties of the grain. In this study, we evaluated the olfactory profile of the EOs of Foeniculum vulgare, Pistacia lentiscus, and Ocimum basilicum, and their toxicity against the main stored grain pest Sitophilus granarius. Trained assessors identified O. basilicum and F. vulgare, as more suitable than the P. lentiscus EO for the wheat treatment. In laboratory tests, the most toxic EO was the P. lentiscus (LC50 = 36.36 μL∙kg−1) while, the least toxic, was the F. vulgare one (LC50 = 77.59 μL∙kg−1). The EOs were also tested combined with diatomaceous earths (DEs) showing synergistic effects (co-toxicity coefficient values ranging from 1.36 to 3.35 for O. basilicum and F. vulgare EOs, respectively). Overall, O. basilicum resulted as the best EO for the wheat treatment, considering its insect toxicity and olfactory profile. In real storage conditions, the wheat co-treated with O. basilicum EO and DEs showed a significantly lower mean infestation (1.5 insect kg−1) than the non-treated wheat (7.0 insect kg−1).

Allium sativum, Rosmarinus officinalis, and Salvia officinalis Essential Oils: A Spiced Shield against Blowflies

“…This usually occurs when the doors are open to allow the unloading of the fresh meat and the loading of the hams. Even if EOs have been extensively studied as topical repellent against insects of medical or veterinary importance [20,[45][46][47], and proposed as repellents in food packaging [48][49][50][51] and stored foodstuff [18,44,52], to the best of our knowledge, this is the first report on the use of an EO-charged mist as an olfactory barrier to protect an indoor working space from the entrance of problematic flies. In line with our results, however, a good efficacy of the EOs as aerosol spray have been reported by Revay et al [53] who observed that a timed-released 0.3% aqueous geraniol emulsion significantly reduced mosquito-biting pressure of Culex pipiens L. and Aedes albopictus Skuse (Diptera: Culicidae) in outdoor conditions.…”

Bioactivity of Different Chemotypes of Oregano Essential Oil against the Blowfly Calliphora vomitoria Vector of Foodborne Pathogens

“…Insects vectors of microorganisms are responsible for the loss and spoilage of a huge quantity of food and the spread of foodborne disease [ 1 ]. Spices EOs are widely used as a food ingredient for their aroma and preservative properties [ 56 ], and their toxic and repellent activity against food insect pests is reported in the literature [ 19 , 20 , 22 , 57 ], but very little is known about their use against synanthropic flies. Here, for the first time, we tested three oregano EOs chemotypes as insecticides and repellents against the blowfly C. vomitoria , which is a synanthropic fly vector of foodborne diseases.…”

“…On the contrary, the essential oils (EOs) of aromatic plants are characterized by low toxicity toward mammalians and high biodegradability [ 18 ]. Moreover, EOs of aromatic plant species, commonly used as food spices, have the advantage of being legally allowed in food and to have a smell profile already accepted by consumers [ 19 , 20 , 21 , 22 , 23 ].…”

Toxicity of Jatropha and Neem Oil Combination on Pink Hibiscus Mealybug

“…When observing the combinations of oils and oil isolated in the direct application route, we found that these results suggested a synergistic action between these oils, where one intensifies the action of the other, depending on the combination. Pierattini et al [27] using three essential oils [Foeniculum vulgare Miller (Apiaceae), Pistacia lentiscus L. (Anacardiaceae) and Ocimum basilicum L. (Lamiaceae)], found a synergistic effect between oil combinations, especially for those containing F. vulgare, that obtained greater efficacy in the mortality of target individuals. Still in this sense, the combination of 90:10% neem oil and jatropha was the treatment with the lowest mortality (15.32%), in direct application, equaling the results presented by the witness.…”