新疆荒漠绿洲稻区稻水象甲危害损失及防治阈值研究

【目的】稻水象甲是水稻的一种毁灭性害虫,也是我国重要的对外检疫性对象之一。该虫自2010年传入新疆后,其发生面积和危害呈不断加重趋势,已对新疆水稻尤其是绿色有机水稻的生产构成了严重威胁。稻水象甲危害造成的产量损失及防治阈值的确定对其准确预测预报及化学防治都具有重要的指导意义。然而,目前尚未见新疆荒漠绿洲稻区的相关报道。【方法】通过田间罩笼试验比较研究了不同虫口密度下的水稻有效穗数、单穗粒数、结实粒及产量等指标,计算得出稻水象甲在新疆的产量允许损失率及防治阈值。【结果】田间稻水象甲成虫数量与水稻有效穗、单穗粒数、结实率存在显著负相关性,但与千粒重关系不显著;逐步线性回归模型分析表明,水稻产量与虫口密度、每公顷穗数、单穗粒数和结实率相关性显著,它们是影响水稻产量的主要因子。此外,新疆荒漠绿洲稻区稻水象甲的产量允许损失率为1.1756%,其防治阈值为5.82头·m~(-2)。【结论】新疆荒漠绿洲稻区允许的稻水象甲越冬代虫口密度最大临界值为5.82头·m~(-2),高于此值应及时进行防治。

Establishing the harm loss and economic threshold of Lissorhoptrus oryzophilus Kuschel for Xinjiang desert oases

Aim] Lissorhoptrus oryzophilus Kuschel is a quarantine pest of rice in China that invaded Xinjiang in 2010. Its continued spread especially threatens organic rice production. Establishing the extent of damage and economic threshold densities, which are currently lacking, is important to develop rational plant protection practices in Xinjiang oases. Method] The relationship between different densities of L. oryzophilus and spike number per hm², no. of grains per spike, 1000-grain mass, rate of filled grain, and yield loss was studied in field tests, using caged plants. Result] There was a significant negative correlation between adult density and effective spike per hm², grains per spike, rate of filled grains, but there was no significant relationship between adult density and 1000-grain mass. Stepwise linear regression analysis showed that rice yield had significant negative correlation with adult density, spike per hm², grains per spike and rate of filled grain. In addition, the damage limit and economic threshold of L. oryzophilus in Xinjiang was calculated as 1.1756% and 5.82 heads·m^-2 respectively. Conclusion] The maximum critical value of overwintering population density of L. oryzophilus in Xinjiang was 5.82 head·m^-2, above this value, interventions are necessary to prevent economic damage.