Here are links to some studies I found:
OREGANO — https://www.ncbi.nlm.nih.gov/pubmed/27568869 Sensitivity of Candida albicans to essential oils: are they an alternative to antifungal agents?
https://www.ncbi.nlm.nih.gov/pubmed/25952773 Composition, antimicrobial, antioxidant, and antiproliferative activity of Origanum dictamnus (dittany) essential oil.
https://www.ncbi.nlm.nih.gov/pubmed/22413147 Effects of cinnamon leaf, oregano and sweet orange essential oils on fermentation and aerobic stability of barley silage.
https://www.ncbi.nlm.nih.gov/pubmed/20438322 In vitro antimicrobial, antioxidant, and antispasmodic activities and the composition of the essential oil of Origanum acutidens (Hand.-Mazz.) Ietswaart.
LEMONGRASS–https://www.ncbi.nlm.nih.gov/pubmed/12803563 Fungicidal and anti-aflatoxigenic effects of the essential oil of Cymbopogon citratus (DC.) Stapf. (lemongrass) against Aspergillus flavus Link. isolated from stored rice.
https://www.ncbi.nlm.nih.gov/pubmed/14615795 Anti-Candida albicans activity of essential oils including Lemongrass (Cymbopogon citratus) oil and its component, citral.
https://www.ncbi.nlm.nih.gov/pubmed/24888440 Essential oils: extraction, bioactivities, and their uses for food preservation.