Abstract
Curcuma longa has well-known insecticidal and repellent effects on insect pests, but its impact on Trichoplusia ni is unknown. In this study, the compound ar-turmerone, extracted and purified from C. longa rhizomes, was identified, and its insecticidal effects, along with turmeric powder, curcuminoid pigments and crude essential oil were evaluated against this important agricultural pest. The role of natural (sesamol and piperonal) and synthetic [piperonyl butoxide (PBO)] synergists under laboratory and greenhouse conditions were also evaluated. The concentration of ar-turmerone in C. longa rhizomes harvested was 0.32% (dwt). Turmeric powder and its derivatives caused 10–20% mortality in third instar T. ni at a very low dose (10 μg/larva). Addition of PBO increased toxicity of turmeric powder and its derivatives (90–97% mortality) in most binary combinations (5 μg of turmeric powder or its derivatives +5 μg of PBO), but neither piperonal nor sesamol were active as synergists. The compound ar-turmerone alone and the combination with PBO reduced larval weight on treated Brassica oleracea in the laboratory and in greenhouse experiments, compared with the negative control. The compound ar-turmerone could be used as a low cost botanical insecticide for integrated management of cabbage looper in vegetable production.
Highlights
The toxicity of natural substances to insect pests can sometimes be comparable to that of synthetic insecticides, but often with less environmental effects[4,8]
Consistent with our results, high concentrations of ar-turmerone in non-polar extracts and essential oils of C. longa have been reported from China (Asia), India (Asia), Nigeria (Africa), Pakistan (Asia), and the islands of Sao Tome and Principe (Africa)[29,45,46,47]
The quantitative and qualitative compositions of plant extracts and essential oils depend on genetic factors and on the environmental conditions of the area where the plant is grown, with variations in the essential oils of C. longa occurring at different localities[30,31,32]
Summary
The toxicity of natural substances to insect pests can sometimes be comparable to that of synthetic insecticides, but often with less environmental effects[4,8]. Turmeric powder is extracted from the dried ground rhizomes of this plant for culinary uses[17,18]. Natural products from this plant have analgesic, antibacterial, antifungal, anti-inflammatory, antioxidant, and digestive properties[19,20] and are under investigation as possible treatments for Alzheimer’s disease, arthritis, diabetes, cardiovascular, liver and kidney problems, several types of cancer, and other clinical disorders[21,22]. The composition and volatility of C. longa essential oils determine the characteristic smell of turmeric, whereas fixed phenolic compounds, such as the pigment curcumin (a diarylheptanoid), its derivatives and other substances, are responsible for the intense yellow color of the rhizomes[33]. Volatile essential oils of C. longa contain a mixture of ketones and sesquiterpene alcohols, the latter mainly based on germacrene and bisabolane skeletons[34,35]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
