Effects of water and nitrogen, phosphorus and potassium nutrition stress of rice seedlings on resistance of brown planthopper

Objective To provide theoretical basis for the comprehensive application of field water and fertilizer to control brown planthopper (BPH), we investigated the effect of water and food on the mortality rate of BPH, and rice seedlings treated with different nitrogen, phosphorus and potassium mass concentrations on the antixenosis and antibiosis of BPH.

Method The BPH mortality under water or food treatments (‘9311’ stem segments, ‘BPHR96’ stem segments, starvation stress with water or without water) was detected with susceptible rice line ‘9311’ and resistant line ‘BPHR96’. Rice seedlings were cultured with low/control/high nitrogen, phosphorus and potassium or low/control/high potassium concentrations nutrient solution in a greenhouse. Five seedling traits including tiller number, plant height, root length, aboveground fresh weight and root fresh weight and BPH survival number, BPH growth rate, honeydew excretion score and host selection number were detected.

Result The BPH mortality increased rapidly in the absence of food. All the BPH treated without food and water died at 48 h after infestation. The mortality was 96.8%, 85.0%, and 44.3% treated with water, ‘BPHR96’ or ‘9311’ stem segments, respectively at 216 h after infestation. Comparing with control or high concentration of nitrogen, phosphorus and potassium, low concentration restricted the growth of rice seedlings, but significantly reduced the survival number, weight gain, honeydew excretion and host selection number of BPH. The effect was more obvious for the resistant rice line. Furthermore, control and high concentration of potassium had no significant effect on the growth of BPH except for rice seedlings compared to low potassium.

Conclusion Water is the primary factor for BPH survival, followed by the palatability of food. Low concentration of nitrogen, phosphorus and potassium treatment can reduce BPH damage to rice seedlings, while high concentration of nitrogen, phosphorus and potassium is beneficial to the invasion of BPH. Therefore, water and fertilizer managements can be applied to the comprehensive control of BPH in the process of rice production.