The parasitic weed genus Striga causes huge losses to crop production in sub-Saharan Africa, estimated to be in excess of $7 billion per year. There is a paucity of reliable distribution data for Striga; however, such data are urgently needed to understand current drivers, better target control efforts, as well as to predict future risks. To address this, we developed a methodology to enable rapid, large-scale monitoring of Striga populations. We used this approach to uncover the factors that currently drive the abundance and distribution of Striga asiatica in Madagascar. Two long-distance transects were established across the middle-west region of Madagascar in which S. asiatica abundance in fields adjacent to the road was estimated. Management, crop structure and soil data were also collected. Analysis of the data suggests that crop variety, companion crop and previous crop were correlated with Striga density. A positive relationship between within-field Striga density and the density of the nearest neighbouring fields indicates that spatial configuration and connectivity of suitable habitats is also important in determining Striga spread. Our results demonstrate that we are able to capture distribution and management data for Striga density at a landscape scale and use this to understand the ecological and agronomic drivers of abundance. The importance of crop varieties and cropping patterns is significant, as these are key socio-economic elements of Malagasy cropping practices. Therefore, they have the potential to be promoted as readily available control options, rather than novel technologies requiring introduction.

中文翻译：

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绘制全国范围内寄生杂草丰度的驱动因素：一种应用于马达加斯加中西部独脚金的新方法

寄生杂草属独脚金给撒哈拉以南非洲的作物生产造成巨大损失，估计每年损失超过 70 亿美元。独脚金缺乏可靠的分布数据；然而，迫切需要此类数据来了解当前的驱动因素、更好地控制目标以及预测未来的风险。为了解决这个问题，我们开发了一种方法来实现对独脚金种群的快速、大规模监测。我们使用这种方法来揭示目前驱动马达加斯加独脚金数量和分布的因素。在马达加斯加的中西部地区建立了两个长距离横断面，其中估计了道路附近田地中的 S. asiatica 丰度。还收集了管理、作物结构和土壤数据。数据分析表明，作物品种、伴生作物和前茬作物与独脚金密度相关。田内独脚金密度与最近相邻田地密度之间的正相关表明，合适栖息地的空间配置和连通性对于决定独脚金的传播也很重要。我们的结果表明，我们能够在景观尺度上捕获独脚金密度的分布和管理数据，并使用它来了解丰度的生态和农艺驱动因素。作物品种和种植模式的重要性非常重要，因为它们是马达加斯加种植实践的关键社会经济要素。因此，它们有可能被推广为现成的控制选项，而不是需要引入的新技术。田内独脚金密度与最近相邻田地密度之间的正相关表明，合适栖息地的空间配置和连通性对于决定独脚金的传播也很重要。我们的结果表明，我们能够在景观尺度上捕获独脚金密度的分布和管理数据，并使用它来了解丰度的生态和农艺驱动因素。作物品种和种植模式的重要性非常重要，因为它们是马达加斯加种植实践的关键社会经济要素。因此，它们有可能被推广为现成的控制选项，而不是需要引入的新技术。田内独脚金密度与最近相邻田地密度之间的正相关表明，合适栖息地的空间配置和连通性对于决定独脚金的传播也很重要。我们的结果表明，我们能够在景观尺度上捕获独脚金密度的分布和管理数据，并使用它来了解丰度的生态和农艺驱动因素。作物品种和种植模式的重要性非常重要，因为它们是马达加斯加种植实践的关键社会经济要素。因此，它们有可能被推广为现成的控制选项，而不是需要引入的新技术。