A novel coffee-leaf bio-lure extracted using NADES for attracting Conopomorpha cramerella

Conopomorpha cramerella is the most damaging insect pest of cacao in Southeast Asia, causing yield losses of up to 80%. Semiochemical-based lures for this species remain limited. Coffee leaves contain chlorogenic acid (CGA), a phenolic compound that acts as an oviposition stimulant. This study aimed to develop a natural bio-lure using coffee leaf extract, evaluate different extraction solvents (methanol vs. Natural Deep Eutectic Solvents (NADES)), compare leaf ages, identify optimal concentrations (10–20%), and test four release media (cotton, pellet, dispenser, and sachet) for their effectiveness in attracting C. cramerella adults. Coffee leaves (Young, semi-mature, and mature) were extracted using Microwave-Assisted Extraction (MAE) with NADES and methanol. Chemical validation was performed using thin-layer chromatography (TLC) to confirm the presence of CGA. Adult C. cramerella were tested using a two-choice olfactometer for six days. Attraction percentages were analysed using ANOVA, Tukey’s HSD, and t-tests. Young leaf extract showed the strongest TLC CGA band intensity. NADES extracts were more attractive than methanol extract. The highest attraction was observed with dispensers (86–90%), followed by sachets (82–83%), pellets, and cotton. Young leaf 10% and 15% extracts yielded significant and highly significant attraction, respectively, compared to the controls. The optimal bio-lure formulation was 10% young-leaf coffee extract + NADES solvent delivered via a dispenser, demonstrating high attraction (up to 90%) and strong CGA confirmation through TLC analysis. This study presents a sustainable, plant-based semiochemical approach for monitoring C. cramerella.