Table 2. Percent contribution of variables to the first five principle components (dimensions = dim.) as revealed via principle component analysis (PCA) and factor analysis with mixed data (FAMD) approaches.
| PCA (dimensions) | |||||
|---|---|---|---|---|---|
| Variable | Dim.1 | Dim.2 | Dim.3 | Dim.4 | Dim.5 |
| Anthracnose | 0.00 | 0.26 | 0.75 | 5.59 | 0.46 |
| Bacterial blight | 0.07 | 0.14 | 0.55 | 0.02 | 0.18 |
| Brown stem rot | 1.46 | 1.10 | 0.06 | 0.76 | 3.53 |
| Cercospora leaf blight (purple seed stain) | 0.04 | 0.50 | 1.18 | 6.54 | 1.55 |
| Charcoal rot | 3.80 | 55.52 | 28.13 | 0.43 | 0.33 |
| Diaporthe-Phomopsis | 0.00 | 1.68 | 2.55 | 35.86 | 6.18 |
| Downy mildew | 0.00 | 0.10 | 0.45 | 0.14 | 0.03 |
| Frogeye leaf spot | 0.01 | 0.25 | 0.43 | 9.95 | 2.16 |
| Fusarium wilt | 1.89 | 5.03 | 0.10 | 0.31 | 3.19 |
| Other diseasesa | 0.02 | 0.01 | 0.00 | 0.06 | 4.14 |
| Phytophthora root and stem rot | 3.48 | 3.91 | 2.39 | 29.41 | 18.23 |
| Pod and stem blight | 0.16 | 0.38 | 1.11 | 0.99 | 0.74 |
| Rhizoctonia aerial blight | 0.01 | 0.08 | 0.01 | 0.33 | 0.04 |
| Root-knot and other nematodesb | 0.13 | 0.00 | 0.27 | 4.55 | 0.23 |
| Sclerotinia stem rot (white mold) | 1.67 | 0.85 | 28.50 | 0.48 | 23.94 |
| Seedling diseasesc | 2.58 | 7.06 | 13.93 | 1.38 | 18.85 |
| Septoria brown spot | 1.08 | 2.50 | 13.30 | 1.33 | 0.53 |
| Southern blight | 0.00 | 0.00 | 0.00 | 0.01 | 0.00 |
| Soybean cyst nematode | 78.77 | 15.62 | 2.75 | 1.37 | 0.27 |
| Soybean rust | 0.01 | 0.06 | 0.04 | 0.19 | 0.02 |
| Stem canker | 0.09 | 0.25 | 0.19 | 0.00 | 0.39 |
| Sudden death syndrome | 4.62 | 4.47 | 3.16 | 0.18 | 14.83 |
| Virus diseasesd | 0.13 | 0.23 | 0.17 | 0.11 | 0.18 |
| FAMD (dimensions) | |||||
| Harvest zonee | 21.55 | 3.92 | 43.68 | 43.14 | 10.48 |
| Regionf | 21.66 | 6.37 | 0.01 | 0.95 | 0.34 |
| Soybean rustg | 2.82 | 37.34 | 1.08 | 2.74 | 1.01 |
| Stateh | 26.39 | 9.24 | 44.99 | 44.69 | 44.51 |
| Total cost due to all diseases | 6.75 | 0.75 | 2.20 | 1.24 | 16.36 |
| Yeari | 3.60 | 37.60 | 2.21 | 3.13 | 10.38 |
| Yield zonej | 17.23 | 4.76 | 5.84 | 4.11 | 16.91 |
a Includes: black root rot, Cercospora leaf blight, Cylindrocladium parasticum (red crown rot), green stem syndrome, Neocosmospora root rot, Pythium root rot, target spot, and Texas root rot.
b Includes: Rotylenchulus reniformis (reniform nematode), Belonolaimus longicaudatus (sting nematode), and Meloidogyne (root-knot nematodes), Helicotylenchus (spiral nematodes), Hoplolaimus (lance nematodes), Paratrichodorus (stubby root nematodes), and Pratylenchus spp. (lesion nematodes).
c Includes: seedling diseases caused by a complex of organisms such as multiple species of Fusarium, Pythium, Phomopsis, and/or Rhizoctonia solani.
d Includes: Alfalfa mosaic virus, Bean pod mottle virus, Bean yellow mosaic virus, Peanut mottle virus, Soybean dwarf virus, Soybean mosaic virus, Soybean vein necrosis virus, Tobacco ringspot virus, Tobacco streak virus, and Tomato spotted wilt virus.
e Represent four levels (zone 1–4) based on the quartiles within a data base containing 588 harvest area (ha) data points (21 years ×28 states). The data points within the minimum to first quartile are classified as harvest zone 1. Similarly, data points from the first quartile to median, median to third quartile, and > third quartile were respectively classified as harvest zones 2, 3, and 4.
f Region relates to states contained in each region as either the northern (consisting of IA, IL, IN, KS, MI, MN, ND, NE, OH, PA, SD, and WI) or southern (consisting of AL, AR, DE, FL, GA, KY, LA, MD, MO, MS, NC, OK, SC, TN, TX, and VA) United States.
g Soybean rust relates to the years that preceded the discovery of the disease in the contiguous U.S. (1996 to 2004) and years since the discovery (2005 to 2016).
h Consisting of the states contained within the study
i Consisting of the years contained within the study (from 1996 to 2016).
j Represent four levels (zone 1–4) based on the quartiles within a data base containing 588 yield (kg/ha) data points (21 years ×28 states). The data points within the minimum to first quartile are classified as yield zone 1. Similarly, data points from the first quartile to median, median to third quartile, and > third quartile were respectively classified as yield zones 2, 3, and 4.