种植密度对桂糖37和桂糖40主要病虫害发生的影响及相关性分析

Influence of planting density on major diseases and insect pests of sugarcane varieties Guitang 37 and Guitang 40 and correlation analysis

为了探讨较佳种植密度,为甘蔗主要病虫害的综合防控提供技术支持,以桂糖37号和桂糖40号为材料,设置5个不同种植密度:11.61、13.58、15.72、17.87和20.01万芽·hm-2,研究种植密度对甘蔗主要病虫害的影响。结果表明,下种量密度对桂糖37的出苗数有明显的影响,当下种量为17.87万芽·hm-2时,出苗数最多。而下种量密度对桂糖40的出苗数没有明显影响。两个品种的出苗率均随着下种量密度的增加而逐渐降低。种植密度对2个甘蔗品种新植蔗的黑穗病发生无明显影响。随着下种量增加,桂糖37梢腐病的发生逐渐加重,然后减轻。桂糖40甘蔗梢腐病较轻,规律不明显。2个品种的花叶病均表现为随着下种量的增加,呈先增加后降低。但2个品种的枯心率均随着下种量的增加而不断上升。相关性分析表明,下种量分别与螟害枯心苗率和出苗数呈显著正相关。种植密度对甘蔗梢腐病、花叶病和螟害均有明显的影响。

Abstract; The present research was conducted to investigate the effects of planting density on control of the major diseases and insect pests in sugarcane field. Two sugarcane varieties Guitang 37 and Guitang 40 were cultivated at five planting densities of 11.61, 13.58, 15.72, 17.87 and 20.01 ten thousand buds·hm-2. The effects of planting density on smut, pokkah boeng, mosaic disease and dead heart seeding of sugarcane were investigated. The results showed that seeding emergence numbers of variety Guitang 37 were significantly affected by planting density, and the maximum number appeared at the density of 17.87 ten thousand buds·hm-2. No obvious relationship between planting density and seeding emergence number was found in Guitang 40. All emergence rates of two sugarcane varieties decreased with an increase of planting density. Planting density had no obvious effect on the incidence of smut during the new planting sugarcane growth period. Along with the increase of seeding quantity, pokkah boeng was heavy, and then became less on variety Guitang 37. Planting density had no obvious effect on that of variety Guitang 40. Mosaic disease incidences of the two varieties increased firstly and then decreased along with the increasing planting density. Interestingly, dead heart seeding constantly increased with an increase of the seeding quantity for both varieties. There was a significantly positive relationship between planting density and seedling emergence number and dead heart seeding. Planting density evidently affected the incidence of sugarcane pokkah boeng, mosaic disease and borer.