scholarly journals Citrus Essential Oils: A Suite of Insecticidal Compounds

2021 ◽  
Author(s):  
Bulbuli Khanikor ◽  
Kamal Adhikari ◽  
Bikash Rabha

Citrus essential oils (CEOs) and their constituent compounds are being reported to have multifarious activities. In this chapter an attempt is made to discuss the insecticidal activities, as well as CEO profile of different vegetative part of Citrus species and biocidal potentiality of their constituent compounds against diverse insect pests. It is observed that in most of the CEO constituent profile, limonene is the major constituent compound. Other important constituents present in different percentages in different CEOs are β-citronellal, linalool, pinene, β- caryophyllene, β-myrcene, terpinene, citral etc. These plant EO constituents are reported to have insecticidal effects against diverse insect species. Taking the four peel EOs of Citrus limon, Citrus paradisi, Citrus medica, Citrus maxima commonly grown in North Eastern part of India, study on their insecticidal effects against Dolichoderus affinis (Hymenoptera: Formicidae) was made and result is presented showing higher fumigant toxicity of C. medica and C. limon oil against the ant sp. With the increasing awareness for using safe insecticidal products among consumers, the citrus EOs with their attracting terpene compounds having good insecticidal potency bear all attributes to be used as commercial green pesticides in coming days both in indoor and outdoor management of insect pests.

Pathogens ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1182
Author(s):  
Roberto Bava ◽  
Fabio Castagna ◽  
Cristian Piras ◽  
Ernesto Palma ◽  
Giuseppe Cringoli ◽  
...  

Varroa destructor is the most important ectoparasitic mite of honey bees that has a negative impact on bee health and honey production. The control programs are mainly based on the use of synthetic acaricides that are often administered indiscriminately. All this has led to drug resistance that now represent a great concern for honey bee farming. The research for alternative products/methods for mites’ control is now mandatory. The aim of this study was to test whether Citrus spp. essential oils could diminish the growth of the V. destructor mite. In Calabria (southern Italy), plants of the Citrus genus are very common and grow both spontaneously and cultured. The essential oils used in this study were extracted from bergamot (Citrus bergamia), grapefruit (Citrus paradisi), lemon (Citrus limon), orange (Citrus sinensis), and mandarin (Citrus reticulata) by hydrodistillation. Every EO was in vitro tested against V. destructor. Each experimental replicate was performed using 35 viable adult female mites (5 for each EO) collected the same day from the same apiary and included negative controls (5 individuals exposed to acetone only) and positive controls (5 individuals exposed to Amitraz diluted in acetone). The essential oils (Eos) were diluted (0.5 mg/mL, 1 mg/mL, and 2 mg/mL) in HPLC grade acetone to obtain the working solution to be tested (50 µL/tube). Mite mortality was manually assessed after 1 h exposure under controlled conditions. The essential oils that showed the best effectiveness at 0.5 mg/mL were bergamot, which neutralized (dead + inactivated) 80% (p ≤ 0.001) of the parasites; grapefruit, which neutralized 70% (p ≤ 0.001); and lemon, which neutralized 69% of them. Interestingly, the positive control (Amitraz) at the same concentration neutralized 60% of the parasites. These results demonstrate that Calabrian bergamot, grapefruit, and lemon Eos consistently reduced V. destructor viability and open the possibility for their utilization to control this parasite in honey bee farming.


2019 ◽  
Vol 26 (3) ◽  
pp. 231-241 ◽  
Author(s):  
María C Luciardi ◽  
M Amparo Blázquez ◽  
María R Alberto ◽  
Elena Cartagena ◽  
Mario E Arena

Citrus essential oils are used in food to confer flavor and aromas. The citrus essential oils have been granted as GRAS and could be used as antimicrobial additives to control bacterial quorum sensing from potential food bacterial pathogens. The chemical composition and inhibitory activity of Citrus paradisi (grapefruit) essential oils obtained by cold-pressed method (EOP) and cold-pressed method followed by steam distillation, against Pseudomonas aeruginosa were determined . The GC-MS analyses of the oil indicated the amount of the essential oil components was highest with D-limonene in both cases. However, the extraction method modified the chemical composition. EOP had higher amount of coumarins and flavonoid as well as less oxygenated terpenoids. At 0.1 mg/mL essential oils were not able to modify the bacterial development but inhibited the P. aeruginosa biofilm production between 52% and 55%, sessile viability between 45% and 48%, autoinducer production and elastase activity between 30% and 56%. Limonene was less effective at inhibiting P. aeruginosa than the essential oils, suggesting a synergistic effect of the minor components. According to our results, grapefruit essential oils could be used as a food preservative to control P. aeruginosa virulence.


Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6284
Author(s):  
Mohamed S. Sedeek ◽  
Abdulaziz M. Al-Mahallawi ◽  
Rania A. A. Hussien ◽  
Ahmed M. Abdelhaleem Ali ◽  
Ibrahim A. Naguib ◽  
...  

The demand for natural fungicides to replace synthetic ones has surged since toxic residues persist in soils, causing environmental contamination and posing a serious threat to worldwide public health. In the context of crop protection and enhancing the efficiency and safety of fungicides, nanotechnology is an eco-friendly strategy in managing fungal pathogens. In the present study, essential oils were isolated from the peels of four citrus fruits (Citrus lemon, Citrus aurantifolia, Citrus maxima, and Citrus sinensis) and were investigated using gas chromatography-mass spectrometric analysis. Monoterpene hydrocarbon was the most predominant group and limonene was the most abundant in the four oils. The antifungal potential of the oils was investigated, and the most active oil (Citrus lemon) was loaded into hexosomal dispersion, and its antifungal potential was retested against the same fungi. The structurally unique nano-based formulation showed great potency for fungal control. To the best of our knowledge, it is the first time the oil of Citrus lemon in nano-hexosomes has been formulated and its fungicidal activity examined. The data collected suggest that citrus essential oils (CEOs), especially when nano-formulated, could be successfully used in integrated fungus management programs.


2019 ◽  
Vol 27 (4) ◽  
pp. 349-353
Author(s):  
H. Bouzeraa ◽  
M. Bessila-Bouzeraa ◽  
N. Labed

Essential oils, when used as bio-insecticides in the control of insect pests of stored grains have shown specificity and variation in the potentiality of their mode of action. In the present study, three essential oils extracted from three aromatic plants of different families, white wormwood (Artemisia herba alba, Asteraceae), oregano (Origanum vulgare, Lamiaceae) and rue (Ruta montana, Rutaceae), were evaluated for their repellent and fumigant toxic potential against the flour moth larvae, Ephestia kuehniella (Lepidoptera, Pyralidae), under laboratory conditions. The essential oils extraction was done by the hydrodistillation method. The repellent activity was carried out in Petri dishes using a filter paper treated with different oil dilutions (25, 75, 100, 120, 130, 150 µL/mL). The fumigant toxicity was determined on three concentrations (50, 130, 150 µL/L air). Two plants were shown to be repellent against the E. kuehniella larvae. Origanum oil was the most repellent with 67% of repellency rate followed by Artemisia oil (46%) at 120µL/mL after 2 hours of exposure. The oil of R. montana had an attractant activity against the larvae and was the most toxic with 56.7% of larval mortality in the first 24 hours. The median lethal concentrations (LC50) recorded were 11.6, 175.4 and 1100.0 µL/L air for the plant oils R. montana, O. vulgare and A. herba alba, respectively. R. montana and O. vulgare essential oil are shown to be efficient with high toxic and repellent properties against E. kuehniella larvae. Their specific potential could be integrated in the selection of the best bioinsecticides for the optimum protection of stored grain.


2021 ◽  
Vol 58 (04) ◽  
pp. 1373-1377
Author(s):  
Muhammad Shah Nawaz ul Rehman

Citrus fruit production is largely affected by different bacterial and fungal pathogens. In Pakistan bacterial diseases like citrus bacterial canker (CBC) pose severe risk to citrus economy. Diagnoses of such diseases could be helpful to avoid the epidemics in nurseries or orchids. In 2011-12, citrus canker symptoms i.e., callus-like outgrowths on leaves and fruits of grape fruit (Citrus paradisi), Washington naval (Citrus sinensis), Kaghzi Limon (Citrus aurantifolia swingle), lemon (Citrus Limon) and pomelo (Citrus maxima) were noticed in Sargodha district of Punjab, Pakistan. Bacteria i.e., yellow mucoid, Xanthomonas- like isolates, were isolated from these lesions. Bacteria isolated from these lesions were cultured and total DNA was isolated. A diagnostic fragment of 581 bp based on rpf genes of Xanthomonas citri pv. citri was amplified, cloned and completely sequenced. BLAST and evolutionary analysis revealed that these isolates show 100% sequence similarity and group with Xanthomonas citri subsp. citri from Argentina (CP023285) and Reunion (CP018858), (CP018854). To our knowledge, this is the first formal report of X. campestris pv. citri pathotypes A on Citrus paradise, Citrus sinensis, Citrus maxima, Citrus Limon and Citrus aurantifolia swingle in Pakistan


Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1270 ◽  
Author(s):  
Simona Nardoni ◽  
Basma Najar ◽  
Baldassare Fronte ◽  
Luisa Pistelli ◽  
Francesca Mancianti

Saprolegnia spp. water molds severely impact fish health in aquaculture, fish farms and hobby fish tanks colonizing mature and immature stages of fishes, as well as eggs. Considering that there are no drugs licensed for treating and/or control the organism, efficient and environmental low-impact methods to control these oomycetes in aquaculture are needed. The aim of the present report was to evaluate the in vitro sensitivity of Saprolegnia parasitica to essential oils (EOs) from Citrus aurantium L., Citrus bergamia Risso et Poiteau, Citrus limon Burm. f., Citrus paradisi Macfad, Citrus sinensis Osbeck, Cinnamomum zeylanicum Blume, Cymbopogon flexuosum (Nees ex Steud.) Watson, Foeniculum vulgare Mill., Illicium verum Hook.f., Litsea cubeba (Lour.) Pers., Origanum majorana L., Origanum vulgare L., Pelargonium graveolens L’Hér., Syzygium aromaticum Merr. & L.M.Perry, and Thymus vulgaris L., by microdilution test. The most effective EOs assayed were T. vulgaris and O. vulgare, followed by C. flexuosum, L. cubeba and C. bergamia. These EOs could be of interest for controlling Saprolegnia infections. Nevertheless, further safety studies are necessary to evaluate if these products could be dispersed in tank waters, or if their use should be limited to aquaculture supplies.


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