Influence of chemical elicitors on induced defence system in cassava (Manihot esculenta Crantz) caused by Sri Lankan Cassava Mosaic Virus

Cassava mosaic disease (CMD) caused by Sri Lankan Cassava Mosaic Virus (SLCMV) is one of the ten most serious crop viral diseases in the world. CMD is found in Vietnam, and since 2016 the disease has caused serious damage to cassava production. The current study was conducted under both greenhouse and field conditions to identify chemical elicitors of host defense against SLCMV. The greenhouse and field experiment were carried out in 2002 and 2023 at School of Agriculture and Forestry, Hue University. The CMD-susceptible variety KM94 was treated before planting by soaking cuttings in solution of each of several chemical elicitors including END- BYE (tannic acid: 25%, tea saponin: 3%), SAT 4SL (cytosinpeptidemycin: 40 g/L), NINGNA STAR 80SL (ningnamycin: 80 g/L), Cruiser Plus 312.5FS (thiamethoxam: 262.5 g/L, difenoconazole: 25 g/L, fludioxonil: 25 g/L), CuCl₂, and salicylic acid (SA) at 1% concentration. Results showed that the effectiveness was highest with Cruiser Plus 312.5FS (30.1%) and lowest with SAT 4SL (14.4%) at 104 days after planting. The AUDPC was highest with untreated plants and lowest with plants treated with Cruiser Plus 312.5FS. Actual yield of plants treated with salicylic acid (25.2 t/ha) was higher than that of untreated plants (18.1 t/ ha). Plants treated with chemical elicitors can improve the yield and starch as compared with untreated plants. As a result, cassava cuttings treated with chemical elicitors are considered a good measure to control cassava mosaic disease.