Effects of silicon fertilizer application on the interaction between rice planthoppers and sheath blight as well as rice yield

【Objective】To explore the potential of application of silicon fertilizer in the prevention and control of rice planthoppers and sheath blight in rice production and its impact on rice yield, which could provide reference for achieving coordinated prevention and control, sustainable management of rice pests and diseases, and increasing rice yield. 【Method】The experiment was conducted in a rice planting base where rice sheath blight and rice planthoppers occurred perennially. Five silicon fertilizer treatments were set up（0, 60, 120, 180 and 240 kg/ha）, and each plot was evenly divided into four sections, transplanted from left to right with insect-susceptible variety TN1, disease-resistant variety 995, insect-resistant variety 22HF1033 and disease-susceptible variety Lemont respectively. At the booting stage, 400 rice planthopper adults were inoculated into each plot, and the population density was surveyed every 10 d. Sheath blight was assessed using the diagonal five-point sampling method to record the disease index, with 3 surveys. Before harvest, the effective panicles, grain number per panicle, filled grain number per panicle, and 1000-grain weight were measured, and the theoretical yield and actual yield were calculated. 【Result】The experiment demonstrated that under CK, TN1 suffered more severe sheath blight damage compared to 22HF1033. In contrast, the difference in planthopper population density between Lemont and 995 was not obvious at most of investigation times. These findings suggested that the increase of planthopper populations could promote the occurrence of rice sheath blight, while the occurrence of rice sheath blight showed no obvious correlation with rice planthopper infestation. With the increased dosage of silicon fertilizer, the disease index of rice sheath blight and the population density of rice planthoppers decreased gradually on all 4 rice varieties tested, significant differences were observed between high dosage silicon fertilizer at the 3^rd survey(October 6^th,2023)（240 kg/ha） and CK treatments（P＜0.05）. As for yield performance, the effective panicle number, grain number per panicle, 1000-grain weight, and seed setting rate of TN1, 22HF1033, Lemont and 995 were enhanced with the increased dosages of silicon fertilizer. And the yield-increasing effect of the 180-240 kg/ha treatment was more obvious. Notably, the actual yield of TN1, 22HF1033, Lemont and 995 increased by 16.83%-28.05%, 18.33%-20.22%, 26.96%-27.54% and 41.58%-50.98% respectively compared to CK. 【Conclusion】Silicon fertilizer has controlling effects on sheath blight and rice planthopper, and greatly improves the yield traits and actual yield of rice. In rice production, considering the economic benefits comprehensively and the control effect of silicon fertilizer on sheath blight and rice planthopper damage and yield-increasing effect, it is recommended that the dosage of silicon fertilizer be 180 kg/ha.