Identification of Active Compounds in Ginger (Zingiber officinale) Extracts and Their Potential for Field Control of the Whitefly (Bemisia tabaci) on Squash

This research was conducted to determine the active compounds in the ethanol extract and essential oil of ginger and to evaluate their roles in reducing whitefly infestation on squash in the field. Chemical analysis revealed that the most prominent peaks in the chromatogram were at 18.528 min (accounting for 60.13% of the total peak area) and at 20.360 min (accounting for 16.13%). A seasonal abundance study of the whitefly showed that immature stages (eggs and nymphs) were present throughout the growing season. There were three distinct population peaks for eggs and nymphs during May and June, with the highest density recorded in mid-May—reaching 70 eggs per leaf and 84.7 nymphs per leaf. Field evaluations demonstrated that the ginger extracts significantly reduced both nymph and egg densities, with the essential oil outperforming the ethanol extract. This effect increased with concentration: at 3 %, the highest relative efficacy against eggs was 88.7 % for the ethanol extract and 90.9 % for the essential oil three days after treatment, while the highest relative efficacy against nymphs was 59.0 % and 88.8 %, respectively. These findings suggest the efficacy of ginger extracts in controlling and reducing whitefly population density in the field.