Screening and application of insect-resistant cassava cultivars suitable for Wuming area

This study aimed to effectively control cassava pests from the source and promote the application of new cassava varieties in Wuming area.

We screened and evaluated insect-resistant cassava cultivars suitable for the Wuming area. The highly resistant cultivar C1115 and the highly susceptible cultivar SC205 were used as references.

Field survey data from 2022 to 2024 showed that SC15, SC9, GR13 and GS1505 all exhibited resistance to both Tetranychus urticae and Paracoccus marginatus, with average damage indexes ranging from 27.29% to 33.36%, and 33.34% to 36.37%, respectively. These values were significantly higher than those for C1115 (10.94% and 11.56%) but significantly lower than those of SC205 (90.57% and 92.24%). Compared to SC205, the average damage indexes were reduced by 57.21%~63.28% and 55.87%~58.90%, respectively. SC12, GS1508, SC5, LIMIN, SC8002 and NZ199 showed moderate resistance to both T. urticae and P. marginatus with average damage indexes ranging from 41.34% to 55.61% and 45.83% to 56.24%, respectively. SC10, SC124, GR4 and GR891 exhibited moderate resistance to T. urticae but were susceptible to P. marginatus with average damage indexes ranging from 48.98% to 56.93% and 66.70% to 69.54%, respectively. SC6068 showed susceptibility to T. urticae but high susceptibility to P. marginatus with average damage indexes of 64.37% and 93.05%, respectively. GR10, KU50 and BREAD were highly susceptible to both T. urticae and P. marginatus with average damage indexes ranging from 93.22% to 95.95% and 95.01% to 95.61%, respectively. Further validation in the Liangjiang, Luoxu, Chengxiang, Taiping and Ningwu areas of Wuming confirmed the resistance performance of SC15, SC9, GR13 and GS1505 to T. urticae and P. marginatus. In these five areas, the average damage indexes ranged from 29.36% to 31.22% and 33.71% to 34.87% for SC15, 31.18% to 33.48% and 34.48% to 35.87% for SC9, 32.45% to 35.53% and 34.86% to 36.46% for GR13, and 34.33% to 35.76% and 35.13% to 36.65% for GS1505, respectively.

The results of this study indicate that SC15, SC9, GR13 and GS1505 exhibit excellent pest resistance to T. urticae and P. marginatus, making them suitable as regionally adapted ideal cultivars for large-scale application in the Wuming area.