Dissecting the economic impact of soybean diseases in the United States over two decades

Soybean (Glycine max L. Merrill) is an economically important commodity for United States agriculture. Nonetheless, the profitability of soybean production has been negatively impacted by soybean diseases. The economic impacts of 23 common soybean diseases were estimated in 28 soybean-producing states in the U.S., from 1996 to 2016 (the entire data set consisted of 13,524 data points). Estimated losses were investigated using a variety of statistical approaches. The main effects of state, year, pre- and post-discovery of soybean rust, region, and zones based on yield, harvest area, and production, were significant on “total economic loss” as a function of diseases. Across states and years, the soybean cyst nematode, charcoal rot, and seedling diseases were the most economically damaging diseases while soybean rust, bacterial blight, and southern blight were the least economically damaging. A significantly greater mean loss (51%) was observed in states/years after the discovery of soybean rust (2004 to 2016) compared to the pre-discovery (1996 to 2003). From 1996 to 2016, the total estimated economic loss due to soybean diseases in the U.S. was $95.48 billion, with $80.89 billion and $14.59 billion accounting for the northern and southern U.S. losses, respectively. Over the entire time period, the average annual economic loss due to soybean diseases in the U.S. reached nearly $4.55 billion, with approximately 85% of the losses occurring in the northern U.S. Low yield/harvest/production zones had significantly lower mean economic losses due to diseases in comparison to high yield/harvest/production zones. This observation was further bolstered by the observed positive linear correlation of mean soybean yield loss (in each state, due to all diseases considered in this study, across 21 years) with the mean state wide soybean production (MT), mean soybean yield (kg ha-1), and mean soybean harvest area (ha). Results of this investigation provide useful insights into how research, policy, and educational efforts should be prioritized in soybean disease management

大豆（Glycine max L. Merrill）是美国农业中极具经济价值的作物。然而，大豆病害严重制约了大豆生产的经济效益。本研究针对美国28个大豆主产州，于1996年至2016年间估算了23种常见大豆病害的经济影响，整个数据集共计13524个数据点。研究采用多种统计学方法对估算得到的病害损失展开分析。州别、年份、大豆锈病发现前后、区域，以及基于产量、收获面积和总产量划分的分区等因素，对病害引发的“总经济损失”均存在显著影响。在所有研究涉及的州份与年份中，大豆胞囊线虫病（soybean cyst nematode）、炭腐病（charcoal rot）及幼苗病害为经济危害程度最高的三类病害；而大豆锈病（soybean rust）、细菌性斑疹病（bacterial blight）及南方菌核病（southern blight）的经济危害程度最低。与大豆锈病发现前（1996年至2003年）相比，发现后的州份及年份（2004年至2016年）的平均病害损失显著提升了51%。1996年至2016年间，美国由大豆病害导致的总估算经济损失达954.8亿美元，其中美国北部地区损失808.9亿美元，南部地区损失145.9亿美元。在整个研究时段内，美国大豆病害年均经济损失接近45.5亿美元，其中约85%的损失发生在美国北部地区。低产、低收获面积及低总产量区域的病害平均经济损失，显著低于高产、高收获面积及高总产量区域。进一步的验证表明，在21年的研究周期内，美国各州因本研究涵盖的所有病害导致的平均大豆产量损失，与该州的平均大豆总产量（单位：公吨）、平均大豆单产（单位：千克/公顷）及平均大豆收获面积（单位：公顷）均呈显著正线性相关。本研究结果可为大豆病害防控领域的科研、政策制定及科普教育工作的优先级规划提供有益参考。