Infection by the fungal pathogen Colletotrichum coccodes affects velvetleaf (Abutilon theophrasti)-soybean competition in the field
Infection by the fungal pathogen Colletotrichum coccodes affects velvetleaf (Abutilon theophrasti)-soybean competition in the field
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DOI：
10.1017/s0043174500094935
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发表时间：
1996-10-01
期刊：
影响因子：
2.5
通讯作者：
Hallett, SG
中科院分区：
文献类型：
--
作者：
Ditommaso, A;Watson, AK;Hallett, SG
1990 年至 1992 年进行了实地研究，以评估真菌病原体（Colletotrichum coccodes）对各种单一栽培和 1:1 混合密度的苋叶种内和种间（与大豆）竞争的影响。在纯林中，施用这种苋叶叶病原体对杂草种子产量的影响很小。在这些地块中，苋叶种内竞争刺激了垂直生长，有利于快速生长。替换过早衰老的患病叶片组织，然而，在混合物中，C. coccodes 接种对两个物种的产量有不同的影响。三年中的两年，与对照（未接种）植物的产量相比，C. coccodes 接种使 velveleaf 种子产量平均降低了 60%。在 C. coccodes 存在的情况下，Velvetleaf 由于大豆种间竞争而遭受了更大的产量损失，特别是在较低的种植面积下密度， 绒叶产量的下降主要归因于病原体的发育迟缓效应，这使得大豆植物能够在杂草之上生长，因此，接种混合地块内的大豆产量损失通常低于对照地块，尽管仅在 1992 年才记录到大豆产量显着增加（23％），无论植物是在单一栽培中还是在混合栽培中，接种处理对两个物种中每果实或种子单位重量产生的种子数量的影响相对较小，研究发现，C. coccodes 对纯林中的绒叶性能影响有限，而在与大豆作物竞争的环境中具有显着更大的影响，这对于仅根据潜在生物防治剂在目标杂草纯林中的效果进行评级的初始功效测试的价值和准确性具有重要影响。
Field research was conducted from 1990 through 1992 to evaluate the effect of the fungal pathogen, Colletotrichum coccodes, on velvetleaf intra- and interspecific (with soybean) competition across a range of monoculture and 1:1 mixture densities, In pure stand, application of this velvetleaf foliar pathogen had little impact on seed yield of the weed, In these plots, velvetleaf intraspecific competition stimulated vertical growth and favored the rapid replacement of diseased leaf tissue that had prematurely senesced, In mixtures, however, C. coccodes inoculation differentially influenced the yield of both species, In two of three years, C. coccodes inoculation reduced velvetleaf seed yields by, an average, 60% compared with yields for control (uninoculated) plants, Velvetleaf suffered greater yield losses from soybean interspecific competition in the presence of C. coccodes, especially at the lower planting densities, The decline in velvetleaf yield was primarily attributed to the stunting effect of the pathogen, which allowed soybean plants to grow above the weed, Consequently, soybean yield losses within inoculated mixture plots were generally lower than for control plots, although significant increases (23%) in soybean yield were recorded only in 1992, The inoculation treatment had relatively little impact on the number of seeds produced per fruit or seed unit weight in both species regardless of whether plants were grown in monocultures or in mixtures, The finding that C. coccodes has only a limited effect on velvetleaf performance in pure stand, while having a significantly greater effect in a competitive environment with a soybean crop, has important ramifications as to the value and accuracy of initial efficacy testing that rates potential biocontrol agents based solely on their effect within pure stands of the target weed.