Richmond D S, Niemczyk H D, Shetlar D J
Department of Entomology, the Ohio State University, OARDC, Wooster 44691, USA.
J Econ Entomol. 2000 Dec;93(6):1662-8. doi: 10.1603/0022-0493-93.6.1662.
Studies were conducted to determine the utility of overseeding endophyte enhanced varieties of perennial ryegrass, Lolium perenne L., into existing stands of Kentucky bluegrass, Poa pratensis L., to manage bluegrass billbug, Sphenophorus parvulus Gyllenhal, larval populations and their damage. Two commercial varieties of endophyte enhanced perennial ryegrass (Repell II and Triple Play) were overseeded at two different rates in the field. S. parvulus larval populations, their damage, and turfgrass composition were monitored over the course of 3 yr. Significantly fewer larvae were found in plots overseeded with Repell II, whereas Triple Play had no significant effect on larval population density. Endophyte infection was confirmed in approximately 58% of all Repell II shoots, whereas only approximately 31% of Triple Play shoots were infected. Regression analysis, using a segmented model, demonstrated that larval populations declined as the proportion of endophyte-infected perennial ryegrass increased. However, no additional reductions in larval population density were achieved in stands containing >40% endophyte-infected perennial ryegrass. Visual damage varied with cultivar, seeding rate, and year, but generally decreased as the proportion of endophyte-infected perennial ryegrass increased. Although seeding rate had an initial effect on turfgrass composition, these differences were not detected after the first year of the study. Results indicate overseeding existing stands of Kentucky bluegrass with endophytic varieties of perennial ryegrass can reduce S. parvulus larval populations and their damage. However, plant genetic characteristics (i.e., different cultivars) may be overriding determinants of many aspects of plant performance including establishment, tolerance to insect feeding, and expression of endophyte-mediated resistance.
开展了多项研究，以确定将内生真菌增强型多年生黑麦草（Lolium perenne L.）补播到现有的草地早熟禾（Poa pratensis L.）草皮中，对防治草地早熟禾象甲（Sphenophorus parvulus Gyllenhal）幼虫种群及其造成的损害是否有效。在田间以两种不同的播种量补播了两种内生真菌增强型多年生黑麦草的商业品种（Repell II和Triple Play）。在3年的时间里，监测了草地早熟禾象甲幼虫种群、其造成的损害以及草坪草的组成。在补播Repell II的地块中发现的幼虫明显较少，而Triple Play对幼虫种群密度没有显著影响。在所有Repell II的茎中，约58%被证实感染了内生真菌，而Triple Play的茎中只有约31%被感染。使用分段模型进行的回归分析表明，随着内生真菌感染的多年生黑麦草比例增加，幼虫种群数量下降。然而，在含有超过40%内生真菌感染的多年生黑麦草的草皮中，幼虫种群密度并没有进一步降低。视觉损伤因品种、播种量和年份而异，但总体上随着内生真菌感染的多年生黑麦草比例增加而减少。虽然播种量对草坪草的组成有初始影响，但在研究的第一年之后没有检测到这些差异。结果表明，用内生真菌品种的多年生黑麦草补播现有的草地早熟禾草皮，可以减少草地早熟禾象甲幼虫种群及其造成的损害。然而，植物遗传特性（即不同的品种）可能是植物表现许多方面的首要决定因素，包括建植、对昆虫取食的耐受性以及内生真菌介导的抗性的表达。
