Management of Fusarium Head Blight (Scab) of Wheat in Arkansas: New Emphasis on Resistant

Management of Fusarium Head Blight (Scab) of Wheat in Arkansas: New Emphasis on Resistant Varieties.

E.A. Milus, W.S. Monfort and R.D. Cartwright

University of Arkansas Division of Agriculture

Department of Plant Pathology

Fusarium Head Blight, or scab, is a very important, albeit erratic, disease of wheat in the United States. The fungus that causes head blight is literally everywhere in Arkansas, and scab disease is stronglyfavored by rainfall before, during, and after flowering of wheat in the spring. In wet Mays, head blight can heavily damage the crop by blighting all or part of the heads.This results in scabby grain containing unacceptable levels of a mycotoxin called deoxynivalenol (DON) that is poisonous to humans and animals. In scabby years, this disease not only reduces yield but makes the grain difficult to sell.

The 2009 harvest year was something of a scab year in Arkansas. Many fields in the state had visible levels of head blight. However, the resulting yield losses, levels of scabby grain and DON were not as bad as would be expected if the rains had come earlier. Nevertheless, the outbreak reminded producers of the importance of this disease, last observed widely in the disastrous year of 1991, when scab ruined the wheat harvest in Arkansas.

Until recently we could only recommend planting varieties that mature at slightlydifferent times and/or vary their planting dates in the fall to spread the risk of flowering at the same time in the springand avoiding rotations with corn or ricebecause these increase the amount of fungus in fields. Recently, new fungicides called Prosaro and Carambahave been registered.These are more effective against head scab than other registered products. However, applying a fungicide at flowering is a new practice for Arkansas wheat growers, and uniform coverage of the heads is essential for best results. Although ground applications have produced the best coverage and control, aerial applications work well enough to be used where scab has been a problem. Furthermore, these fungicides work better on cultivars with some resistance to scab.

A project funded by the U.S. Wheat and Barley Scab Initiative – a federal multistate research project – and wheat disease research funded by the Arkansas Wheat Promotion Board during the past two years have resulted in considerable data on the head blight reactions of wheat varieties planted in the state. Resistance can be measured by the percentage of florets blighted and by the percentage of scabby grain. The level of DON in grain under scab pressure is the most reliable indicator of resistance. From inoculated and misted head blight nurseries at Fayetteville in 2008 and 2009, we visually estimated the percentage of blighting on heads andthe percentage of scabby seed that resulted. The levels of DON in the grain were measured by a lab at the University of Minnesota. Also, the percentage of scabby seed in grain harvested from plots at various research centers across the state was visually estimated. We ranked the reaction of each variety within location, and summed these ranks across all environments to determine which varieties appeared to be the most consistently resistant to head scab. Therefore, varieties with lower combined ranks would be better choices than those with higher combined ranks.

Based on results from inoculated and misted nurseries at Fayetteville in 2008 and 2009 (Table 1) and from natural infection across five locations in Arkansas in 2009 (Tables 2 and 3), a few varieties currently marketed in Arkansas appeared to have moderate resistance to head blight. Progeny 166 ranked better than Bess, the moderately resistant check, for a combination of head blight severity, percentage of scabby kernels and DON level in both 2008 and 2009 inoculated and misted nurseries (Table 1). Across five locations with natural infection, Progeny 166 ranked 2nd out of 20 varieties at Kibler (Table 2) and 17th out of 90 entries in the 2009 Arkansas Wheat Variety Test (Table 3). However, Progeny 166 may be the same genotype as Dixie 900 that ranked 2nd for the same comparisons. Dixie Bell DB1002 and Delta Grow 4500 ranked 1st and 3rd, respectively, across the four locations (Table3). In addition to Progeny 166, Armor 5110 and AGS 2050 also ranked better than Bess in the 2008 inoculated and misted nursery (Table 1).Although interpreting these results is complicated because all varieties were not in all tests and because pedigrees and previous head blight reactions are not available for most licensed varieties, these results are the first comprehensive summary of head blight resistance among varieties currently soldin Arkansas. By checking the yield performance in the Arkansas Wheat Update ( against varieties in the following data tables with lower scab potential, users can make better planting choices this fall. If nothing else, avoiding varieties with the highest scab potential should result in lower risk next spring. Furthermore, since head blight resistance may not provide complete protection under all conditions, a combination of a moderately resistant variety with a well-timed application of Prosaro or Caramba in the spring – if weather conditions warrant – would be the most effective management strategy overall.

Table 1. Reaction of Wheat Varieties to Head Scab Disease in Arkansas inthe 2008 and 2009 Inoculated/Irrigated Nurseries at Fayetteville.

FHB Severity / % Scabby Seed / DON ppm / Sum of Ranks
2008 Entries / Mean / Rank / Mean / Rank / Mean / Rank / All 3 traits
Armor 5110 / 12 / 2 / 16 / 2 / 2.6 / 1 / 5
Progeny 166 / 15 / 4 / 14 / 1 / 3.5 / 3 / 8
AGS2050 / 17 / 5 / 23 / 6 / 2.9 / 2 / 13
Delta Grow 4500 / 15 / 4 / 27 / 7 / 3.7 / 4 / 15
AgriPro/Coker Beretta / 15 / 4 / 18 / 4 / 5.1 / 7 / 15
Bess (Res. Check) / 13 / 3 / 17 / 3 / 6.5 / 9 / 15
Delta King 7710 / 18 / 6 / 20 / 5 / 4.0 / 5 / 16
Croplan Genetics 8302 / 17 / 5 / 28 / 8 / 7.5 / 11 / 24
Pioneer 26R15 / 17 / 5 / 40 / 10 / 8.0 / 13 / 28
Dixie 989 / 25 / 8 / 50 / 15 / 4.6 / 6 / 29
Delta Grow 1600 / 25 / 8 / 50 / 15 / 6.1 / 8 / 31
Hornbeck 3266 / 27 / 9 / 40 / 10 / 7.9 / 12 / 31
Pioneer 26R87 / 27 / 9 / 27 / 7 / 11.2 / 16 / 32
Croplan Genetics 554w / 23 / 7 / 47 / 13 / 9.1 / 14 / 34
Terral 8558 / 33 / 12 / 48 / 14 / 7.3 / 10 / 36
AgriPro/Coker 9553 / 25 / 8 / 45 / 12 / 11.4 / 17 / 37
Pioneer 26R22 / 32 / 11 / 43 / 11 / 10.8 / 15 / 37
Pat / 7 / 1 / 57 / 18 / 11.5 / 18 / 37
AGS 2000 / 33 / 12 / 32 / 9 / 12.3 / 19 / 40
AgriPro/Coker Magnolia / 28 / 10 / 52 / 16 / 12.5 / 20 / 46
Coker 9835 (Sus. check) / 80 / 14 / 54 / 17 / 12.7 / 21 / 52
Terral LA 841 / 43 / 13 / 73 / 19 / 15.5 / 22 / 54
LSD (P=0.05) / 9 / 17.2 / 4.6
2009 entries
Progeny 166 / 12 / 2 / 1 / 1 / 1.2 / 1 / 4
Bess (Res. check) / 6 / 1 / 2 / 2 / 2.1 / 4 / 7
USG 3555 / 17 / 4 / 3 / 3 / 1.6 / 2 / 9
Roane / 12 / 2 / 3 / 3 / 2.4 / 6 / 11
Dixie 454 / 18 / 5 / 3 / 3 / 1.8 / 3 / 11
Progeny 185 / 15 / 3 / 5 / 5 / 2.1 / 5 / 13
Terral 8558 / 22 / 7 / 5 / 5 / 2.7 / 7 / 19
AGS 2031 / 22 / 7 / 5 / 5 / 3.1 / 9 / 21
Terral LA 841 / 27 / 10 / 6 / 6 / 2.7 / 7 / 23
HBK 3266 / 25 / 9 / 6 / 6 / 2.8 / 8 / 23
Delta Grow 1600 / 20 / 6 / 5 / 5 / 4.0 / 12 / 23
Pioneer 26R15 / 17 / 4 / 7 / 7 / 4.3 / 14 / 25
Pioneer 26R22 / 23 / 8 / 4 / 4 / 4.2 / 13 / 25
Croplan 8302 / 17 / 4 / 6 / 6 / 4.5 / 16 / 26
Armor 360Z / 22 / 7 / 8 / 8 / 3.7 / 11 / 26
AgriPro Beretta / 12 / 2 / 5 / 5 / 5.4 / 20 / 27
Delta King 9577 / 32 / 13 / 7 / 7 / 3.2 / 10 / 30
AGS 2060 / 23 / 8 / 9 / 9 / 4.7 / 17 / 34
Dixie 427 / 30 / 12 / 9 / 9 / 4.4 / 15 / 36
AgriPro/Coker 9553 / 28 / 11 / 12 / 11 / 5.3 / 18 / 40
Delta Grow 7400 / 20 / 6 / 12 / 11 / 6.9 / 23 / 40
Croplan 554W / 33 / 14 / 10 / 10 / 5.3 / 19 / 43
AgriPro Magnolia / 32 / 13 / 12 / 11 / 6.5 / 22 / 46
Coker 9835 (Sus. Check) / 43 / 15 / 20 / 12 / 5.8 / 21 / 48
LSD (P=0.05) / 17 / 6 / 3.5

Table 2. Reaction of Wheat Varieties to Head Scab Disease as measured by percentage of scabby seed at Kibler in 2009.

Scabby Seed
Variety / % / Rank
Dixie 454 / 0.3 / 1
Progeny 166 / 0.7 / 2
Croplan 8302 / 0.8 / 3
Roane / 1.2 / 4
Terral 8558 / 1.2 / 4
Progeny 185 / 1.3 / 5
AgriPro Beretta / 1.3 / 5
USG 3555 / 1.4 / 6
Croplan 554W / 1.4 / 6
Pioneer 26R22 / 1.7 / 7
Delta King 9577 / 1.7 / 7
AgriPro/Coker 9553 / 1.7 / 7
Pioneer 26R15 / 2.3 / 8
Dixie 427 / 2.4 / 9
AGS 2060 / 2.6 / 10
HBK 3266 / 2.7 / 11
Armor 360Z / 2.8 / 12
Delta Grow 7400 / 3.2 / 13
Delta Grow 1600 / 3.3 / 14
AGS 2031 / 3.7 / 15
AgriPro Magnolia / 3.9 / 16
Terral LA 841 / 4.8 / 17
LSD (P=0.05) / 2.3

Table 3. Reaction of Wheat Varieties in the 2009 Arkansas Wheat Variety Test for Head Scab Disease as measured by percentage of Scabby Seed at 4 Locations in Arkansas (sorted by sum of ranks).

% Scabby Seed and Rank within Location
Marianna / Newport / Stuttgart / Keiser / Average for 4 Locations / Sum of Ranks
Variety / % / Rank / % / Rank / % / Rank / % / Rank / % / 4 Locations
DIXIE BELL DB1002 / 0.3 / 2 / 5.0 / 3 / 0.3 / 1 / 1.0 / 4 / 1.6 / 10
DIXIE 900 / 0.3 / 2 / 5.0 / 3 / 1.3 / 4 / 1.0 / 4 / 1.9 / 13
DELTA GROW 4500 / 0.0 / 1 / 5.5 / 5 / 1.5 / 5 / 1.0 / 4 / 2.0 / 15
VA04W-90 / 2.8 / 11 / 4.3 / 1 / 1.0 / 3 / 0.3 / 1 / 2.1 / 16
PROGENY 130 / 1.3 / 6 / 4.5 / 2 / 1.5 / 5 / 0.8 / 3 / 2.0 / 16
DELTA GROW 5200 / 2.0 / 9 / 4.5 / 2 / 1.0 / 3 / 0.8 / 3 / 2.1 / 17
AGRIPRO/COKER BERETTA / 1.3 / 6 / 4.5 / 2 / 1.3 / 4 / 1.3 / 5 / 2.1 / 17
DIXIE BELL DB2125 / 2.3 / 10 / 5.5 / 5 / 0.8 / 2 / 0.5 / 2 / 2.3 / 19
DIXIE 454 / 0.3 / 2 / 6.5 / 7 / 1.3 / 4 / 1.5 / 6 / 2.4 / 19
LEGACY LW303 / 2.0 / 9 / 5.3 / 4 / 1.3 / 4 / 0.8 / 3 / 2.3 / 20
PROGENY 119 / 1.5 / 7 / 5.0 / 3 / 0.8 / 2 / 2.0 / 8 / 2.3 / 20
DIXIE 907 / 1.3 / 6 / 5.5 / 5 / 2.0 / 7 / 0.8 / 3 / 2.4 / 21
AGRIPRO/COKER OAKES / 0.8 / 4 / 4.5 / 2 / 3.0 / 11 / 1.0 / 4 / 2.3 / 21
ROANE / 1.3 / 6 / 4.5 / 2 / 2.3 / 8 / 1.3 / 5 / 2.3 / 21
AG ALUMNI 3080 / 1.3 / 6 / 7.0 / 8 / 2.0 / 7 / 0.5 / 2 / 2.7 / 23
TERRAL TV8170 / 0.3 / 2 / 8.5 / 12 / 2.0 / 7 / 0.8 / 3 / 2.9 / 24
PROGENY 166 / 0.8 / 4 / 8.3 / 11 / 1.8 / 6 / 1.0 / 4 / 3.0 / 25
USG 3770 / 1.0 / 5 / 5.0 / 3 / 4.0 / 15 / 0.8 / 3 / 2.7 / 26
DIXIE 940 / 0.5 / 3 / 8.0 / 10 / 2.3 / 8 / 1.3 / 5 / 3.0 / 26
DIXIE BELL DB21250 / 0.8 / 4 / 11.0 / 18 / 1.3 / 4 / 0.3 / 1 / 3.3 / 27
LEGACY LW-262 / 0.8 / 4 / 6.0 / 6 / 2.0 / 7 / 2.5 / 10 / 2.8 / 27
JAMESTOWN / 2.8 / 11 / 4.5 / 2 / 2.3 / 8 / 1.8 / 7 / 2.8 / 28
DELTA GROW 1600 / 0.5 / 3 / 7.5 / 9 / 1.8 / 6 / 2.5 / 10 / 3.1 / 28
PROGENY 185 / 3.0 / 12 / 5.5 / 5 / 2.3 / 8 / 1.0 / 4 / 2.9 / 29
DIXIE BELL DB7440 / 1.5 / 7 / 7.0 / 8 / 2.3 / 8 / 1.5 / 6 / 3.1 / 29
CROPLAN GENET. 8302 / 1.5 / 7 / 6.0 / 6 / 2.8 / 10 / 1.5 / 6 / 2.9 / 29
PROGENY 117 / 1.0 / 5 / 5.5 / 5 / 3.5 / 13 / 1.5 / 6 / 2.9 / 29
ARMOR GOLD / 1.8 / 8 / 10.5 / 17 / 1.5 / 5 / 1.0 / 4 / 3.7 / 34
AGS 2050 / 1.8 / 8 / 9.5 / 14 / 2.3 / 8 / 1.3 / 5 / 3.7 / 35
PIONEER VARIETY / 0.8 / 4 / 7.0 / 8 / 5.0 / 18 / 1.3 / 5 / 3.5 / 35
PIONEER 26R15 / 1.0 / 5 / 10.5 / 17 / 3.5 / 13 / 0.3 / 1 / 3.8 / 36
ARMOR RENEGADE / 1.8 / 8 / 10.3 / 16 / 2.3 / 8 / 1.5 / 6 / 3.9 / 38
USG 3555 / 4.5 / 18 / 7.0 / 8 / 3.0 / 11 / 0.5 / 2 / 3.8 / 39
DELTA KING DK 9108 / 1.3 / 6 / 11.5 / 19 / 2.3 / 8 / 1.5 / 6 / 4.1 / 39
AGS 2055 / 1.0 / 5 / 10.3 / 16 / 2.3 / 8 / 2.8 / 11 / 4.1 / 40
HBK 3443 / 1.0 / 5 / 10.5 / 17 / 2.3 / 8 / 2.8 / 11 / 4.1 / 41
ARLA1120-56-7-C / 8.0 / 23 / 6.5 / 7 / 3.0 / 11 / 1.0 / 4 / 4.6 / 45
AGRIPRO/COKER 9700 / 3.3 / 13 / 7.5 / 9 / 5.5 / 19 / 1.5 / 6 / 4.4 / 47
AG ALUMNI 1370 / 0.8 / 4 / 12.3 / 21 / 3.5 / 13 / 2.3 / 9 / 4.7 / 47
USG 3295 / 3.3 / 13 / 8.8 / 13 / 4.0 / 15 / 1.8 / 7 / 4.4 / 48
AGRIPRO/COKER W1377 / 1.0 / 5 / 11.5 / 19 / 4.0 / 15 / 2.3 / 9 / 4.7 / 48
PIONEER VARIETY26R87 / 4.0 / 16 / 5.5 / 5 / 7.5 / 23 / 1.5 / 6 / 4.6 / 50
ARMOR ARX 6202 / 2.5 / 10 / 13.8 / 26 / 1.8 / 6 / 2.0 / 8 / 5.0 / 50
AGS 2031 / 4.0 / 16 / 8.5 / 12 / 5.5 / 19 / 1.0 / 4 / 4.8 / 51
AGRIPRO/COKER 9553 / 4.5 / 18 / 6.0 / 6 / 7.0 / 22 / 1.5 / 6 / 4.8 / 52
TERRAL TV8558 / 5.0 / 19 / 13.5 / 25 / 1.5 / 5 / 1.3 / 5 / 5.3 / 54
PIONEER VARIETY XW07B / 4.0 / 16 / 11.5 / 19 / 3.3 / 12 / 1.8 / 7 / 5.1 / 54
VA03W-412 / 4.5 / 18 / 9.8 / 15 / 5.0 / 18 / 1.3 / 5 / 5.1 / 56
PIONEER VARIETY 26R22 / 4.5 / 18 / 6.5 / 7 / 9.3 / 24 / 2.0 / 8 / 5.6 / 57
LA01158D-55-8-B / 2.8 / 11 / 10.5 / 17 / 4.8 / 17 / 3.3 / 13 / 5.3 / 58
DIXIE 989 / 2.3 / 10 / 11.0 / 18 / 3.8 / 14 / 4.0 / 16 / 5.3 / 58
TERRAL TV8589 / 1.3 / 6 / 16.5 / 31 / 3.5 / 13 / 2.5 / 10 / 5.9 / 60
LEGACY LW-117 / 0.5 / 3 / 17.5 / 33 / 1.5 / 5 / 6.0 / 19 / 6.4 / 60
USG 3665 / 5.0 / 19 / 12.5 / 22 / 2.8 / 10 / 2.5 / 10 / 5.7 / 61
CROPLAN GENET.554W / 1.5 / 7 / 17.7 / 34 / 4.5 / 16 / 1.3 / 5 / 6.2 / 62
USG 3409 / 4.5 / 18 / 15.0 / 29 / 2.5 / 9 / 1.8 / 7 / 5.9 / 63
DYNA-GRO SHIRLEY / 2.5 / 10 / 12.5 / 22 / 6.5 / 21 / 2.8 / 11 / 6.1 / 64
DYNA-GRO 9922 / 2.3 / 10 / 16.3 / 30 / 2.8 / 10 / 3.5 / 14 / 6.2 / 64
ARMOR 360Z / 4.5 / 18 / 13.8 / 26 / 3.0 / 11 / 2.8 / 11 / 6.0 / 66
AGRIPRO/ COKER MAGNOLIA / 2.5 / 10 / 18.8 / 35 / 4.5 / 16 / 2.0 / 8 / 6.9 / 69
GA 991209-6E33 / 3.5 / 14 / 16.3 / 30 / 4.0 / 15 / 2.5 / 10 / 6.6 / 69
CROPLAN GENETIC. 8868 / 5.5 / 20 / 12.0 / 20 / 3.8 / 14 / 4.0 / 16 / 6.3 / 70
LA01110D-84-1-C / 4.5 / 18 / 15.0 / 29 / 5.0 / 18 / 1.5 / 6 / 6.5 / 71
AR97044-10-1 / 3.5 / 14 / 14.5 / 28 / 4.5 / 16 / 3.3 / 13 / 6.4 / 71
DELTA KING DK 9577 / 3.8 / 15 / 14.0 / 27 / 3.5 / 13 / 4.3 / 17 / 6.4 / 72
LEGACY LW410 / 9.8 / 25 / 10.3 / 16 / 5.0 / 18 / 3.5 / 14 / 7.1 / 73
PAT / 0.5 / 3 / 19.5 / 37 / 4.0 / 15 / 6.0 / 19 / 7.5 / 74
USG 3209 / 5.0 / 19 / 16.7 / 32 / 5.0 / 18 / 1.8 / 7 / 7.1 / 76
AR99174-5-1 / 4.3 / 17 / 13.3 / 24 / 7.0 / 22 / 3.5 / 14 / 7.0 / 77
AGS 2060 / 3.3 / 13 / 17.5 / 33 / 6.5 / 21 / 2.8 / 11 / 7.5 / 78
LA01110D-150 / 5.0 / 19 / 19.0 / 36 / 5.0 / 18 / 1.5 / 6 / 7.6 / 79
AGRIPRO/COKER 9804 / 13.0 / 29 / 12.8 / 23 / 10.0 / 25 / 1.0 / 4 / 9.2 / 81
HBK 3266 / 5.5 / 20 / 17.5 / 33 / 5.5 / 19 / 2.3 / 9 / 7.7 / 81
GA 991371-6E12 / 2.8 / 11 / 27.5 / 43 / 3.8 / 14 / 3.3 / 13 / 9.3 / 81
DIXIE 427 / 5.0 / 19 / 15.0 / 29 / 5.5 / 19 / 3.5 / 14 / 7.3 / 81
SABBE / 2.5 / 10 / 22.5 / 39 / 3.5 / 13 / 7.0 / 20 / 8.9 / 82
AGS 2026 / 5.5 / 20 / 15.0 / 29 / 7.0 / 22 / 3.0 / 12 / 7.6 / 83
AR99110W-13-1 / 1.5 / 7 / 23.8 / 41 / 3.5 / 13 / 9.5 / 22 / 9.6 / 83
VA04W-259 / 3.5 / 14 / 22.5 / 39 / 4.5 / 16 / 3.8 / 15 / 8.6 / 84
ARLA1008-12-2-C / 3.0 / 12 / 27.5 / 43 / 4.0 / 15 / 4.0 / 16 / 9.6 / 86
ARMOR ARX 840 / 11.3 / 27 / 18.8 / 35 / 6.0 / 20 / 1.5 / 6 / 9.4 / 88
LA01140D-70 / 4.5 / 18 / 21.3 / 38 / 6.5 / 21 / 2.8 / 11 / 8.8 / 88
PROGENY 136 / 6.0 / 21 / 17.5 / 33 / 4.5 / 16 / 5.8 / 18 / 8.4 / 88
LA01110D-181-6--B / 8.3 / 24 / 22.5 / 39 / 6.0 / 20 / 2.3 / 9 / 9.8 / 92
GA 991336-6E9 / 3.8 / 15 / 21.3 / 38 / 5.0 / 18 / 7.3 / 21 / 9.3 / 92
TERRAL LA841 / 12.0 / 28 / 25.0 / 42 / 5.0 / 18 / 1.3 / 5 / 10.8 / 93
TX4A35 / 11.0 / 26 / 13.5 / 25 / 15.8 / 26 / 5.8 / 18 / 11.5 / 95
GA 981621-5E34 / 3.0 / 12 / 23.3 / 40 / 7.0 / 22 / 10.7 / 23 / 11.0 / 97
HBKX3546 / 4.0 / 16 / 21.3 / 38 / 7.0 / 22 / 13.5 / 24 / 11.4 / 100
GA 981622-5E35 / 6.8 / 22 / 25.0 / 42 / 6.0 / 20 / 7.0 / 20 / 11.2 / 104
LSD (0.05) / 3.1 / 7.1 / 3.1 / 3.3 / 3.9