Exploring the Efficacy of Four Apiaceae Essential Oils against Nine Stored-Product Pests in Wheat Protection.

The Apiaceae family, known for aromatic plants producing bioactive essential oils (EOs), holds significance across sectors, including agrochemicals. This study evaluated the insecticidal potential of four Apiaceae EOs from Crithmum maritimum L., Trachyspermum ammi (L.) Sprague ex Turrill, Smyrnium olusatrum L., and Elwendia persica (Boiss.) Pimenov and Kljuykov against various significant storage pests (Sitophilus oryzae (L.), Trogoderma granarium Everts, Rhyzopertha dominica (F.), Tribolium castaneum (Herbst), T. confusum Jacquelin du Val, Oryzaephilus surinamensis (L.), Alphitobius diaperinus (Panzer), Acarus siro L., and Tenebrio molitor L.) on wheat. Insect mortality rates were monitored at intervals of 1, 2, 3, 4, 5, 6, and 7 days. Smyrnium olusatrum EO exhibited the highest efficacy, followed by T. ammi, C. maritimum, and E. persica EOs, although efficacy varied by species, developmental stage, and concentration. Notably, complete mortality occurred for several pests at 1000 ppm of S. olusatrum and T. ammi EOs. Gas chromatography-mass spectrometry (GC-MS) analysis revealed key compounds in these EOs, including myrcene, germacrone, and curzerene in S. olusatrum EO, and thymol, γ-terpinene, and p-cymene in T. ammi EO. These findings emphasize their potential as botanical insecticides. Smyrnium olusatrum and T. ammi EOs emerge as promising eco-friendly pest management options due to their efficacy, highlighted compound composition, and availability of biomass from both wild and cultivated sources.

Acmella oleracea extracts as green pesticides against eight arthropods attacking stored products.

Developing sustainable control tools for managing noxious pests attacking stored foodstuffs is a timely research challenge. Acmella oleracea (L.) R. K. Jansen is a crop widely cultivated for its multiple usages on an industrial level. In this study, the extracts prepared with A. oleracea aerial parts were applied on wheat kernels for the management of eight important arthropod pests attacking stored products, i.e., Cryptolestes ferrugineus, Tenebrio molitor, Oryzaephilus surinamensis, Trogoderma granarium, Tribolium castaneum, Tribolium confusum, Alphitobius diaperinus (adults/larvae), and Acarus siro (adults/nymphs). Extraction of A. oleracea was optimized on the base of the yield and content of spilanthol and other N-alkylamides which were analysed by HPLC-DAD-MS. Two concentrations of n-hexane or methanol extracts (500 ppm and 1000 ppm), obtained through Soxhlet extraction, were tested to acquire mortality data on the above-mentioned pests after 4, 8, and 16 h and 1 to 7 days of exposure. Both extracts achieved complete mortality (100.0%) of C. ferrugineus adults. In the case of A. diaperinus adults, mortalities were very low at any concentrations of both extracts. In general, the n-hexane extract was more efficient than methanol extract against almost all species and stages. Considering both extracts, the susceptibility order, from most to least susceptible species/stage, was C. ferrugineus adults > A. diaperinus larvae > C. ferrugineus larvae > T. granarium adults > T. molitor larvae > O. surinamensis adults > O. surinamensis larvae > T. confusum larvae > T. castaneum larvae > A. siro adults > T. molitor adults > A. siro nymphs > T. granarium larvae > T. castaneum adults > T. confusum adults > A. diaperinus adults. Our research provides useful knowledge on the efficacy of N-alkylamides-rich A. oleracea extracts as grain protectants, pointing out the importance of targeting the most susceptible species/ developmental stages.

Insecticidal efficacy of the essential oil of jambú (Acmella oleracea (L.) R.K. Jansen) cultivated in central Italy against filariasis mosquito vectors, houseflies and moth pests.

ETHNOPHARMACOLOGICAL RELEVANCE: Acmella oleracea (L.) R.K. Jansen (Compositae), well-known as jambú, is a medicinal herb of pungent taste, native to Brazil but cultivated in different parts of the world due to its aromatic and pharmacological properties. In folk medicine, the plant has been used against parasites and to combat insects and mites. No data are available on the insecticidal activity of jambú essential oil. AIM OF THE STUDY: To test the jambú essential oil obtained from A. oleracea cultivated in central Italy against the filariasis vector, Culex quinquefasciatus, the Egyptian cotton worm, Spodoptera littoralis, and the housefly, Musca domestica. MATERIALS AND METHODS: The chemical composition of the essential oil was achieved by GC-FID and GC-MS analyses. Acute toxicity experiments were conducted on larvae of the filariasis vector C. quinquefasciatus and S. littoralis and adults of M. domestica to determine the LC50(LD50) and LC90(LD90) values of the oil, along with the positive control, α-cypermethrin. RESULTS: (E)-caryophyllene (20.8%), ß-pinene (17.3%), myrcene (17.1%) and caryophyllene oxide (10.0%) were the major volatile constituents. Interestingly, the oil contained little amounts (3.9%) of the insecticidal spilanthol. Jambú essential oil exerted relevant effects on C. quinquefasciatus (LC50 = 42.2 mg L-1, LC90 = 73.6 mg L-1) and S. littoralis 3rd instar larvae (LD50 = 68.1 µg larva-1, LD90 = 132.1 µg larva-1). High acute toxicity was also detected testing the jambú oil against adult females of M. domestica, achieving a LD50 value of 44.3 µg adult-1 and a LD90 value of 87.5 µg adult-1. CONCLUSIONS: Taken together our data support the traditional use of jambú as an insecticidal agent and represent the scientific basis for the industrial exploitation of the essential oil in the fabrication of green insecticides.