Review of Potato Trials for Psyllid Control in Scottsbluff, Nebraska, 2000-10
Summary: Trials were conducted for the control of potato psyllid at the Univ. Nebraska's Panhandle REC, Scottsbluff, from 2000 to 2010. Psyllid data on seed and furrow application of imidacloprid and thiamethoxam insecticides were collected in 2000, 2001, 2002, and 2005. Psyllid data on foliar-applied insecticides were collected in 2005, 2006, 2007, and 2010. There were no psyllid observations in 2004, 2008, and 2009, and there was no trial in 2003.
Foliar Treatments
Multi-year psyllid data are only available on Oberon among the foliar-applied insecticides. Table A summarizes the results from 2006, 2007, and 2010. The most effective treatment was Oberon applied at 16 fl oz/acre. This significantly reduced plant injury from psyllids with a concomitant increase in yield. Note that injury was not completely eliminated and yield would be below the level of no psyllid infestation.
Table A. Summary of Oberon foliar insecticide on psyllid injury and yield.
All seed was cut and treated with Maxim FS by Western Potato Inc.
All seed was cultivar Atlantic.
| Foliar Product | Rate /a | Plants with Injury, % | Yield US#1 cwt/a | Trial Years |
| none | ---- | 62 A | 190 C | 2006,07,10 |
| standard* | ---- | 43 AB | 227 AB | 2006,07,10 |
| Oberon | 8 fl oz | 47 A | 203 BC | 2006,07,-- |
| Oberon | 12 fl oz | 25 BC | 229 AB | 2006,07,10 |
| Oberon | 16 fl oz | 15 C | 262 A | 2006,07,10 |
Seed and Furrow Treatments
Multi-year psyllid data are available for both imidacloprid and thiamethoxam insecticides applied to seed (Gaucho/Genesis and Adage/Cruiser) and into the furrow at planting (Admire and Platinum). Tables A and B summarize the results from 2000, 2001, 2002, and 2005. All treatments reduced psyllid injury and usually increased yield. No clear distinction can be made between the methods of application, seed treatment (dust or liquid) and in-furrow at planting. Likewise, where the two chemistries were in the same trial, no distinction could be made between them.
Table B. Summary of imidacloprid insecticide on psyllid injury and yield.
Seed fungicide was Tops MZ. All seed was cultivar Atlantic.
| Seed Product | Furrow Product | Plants with Injury, % | Yield US#1 cwt/a | Trial Years |
| none | none | 14 A | 318 B | 2000,01,02 |
| Gaucho or Genesis | none | 0.8 B | 339 AB | 2000,01,02 |
| none | Admire | 0.9 B | 362 A | 2000,01,02 |
Table C. Summary of thiamethoxam insecticide on psyllid injury and yield.
Seed fungicide was Maxim MZ. All seed was cultivar Atlantic.
| Seed Product | Furrow Product | Plants with Injury, % | Yield US#1 cwt/a | Trial Years |
| none | none | 31 A | 251 B | 2001,02,05 |
| Adage or Cruiser | none | 0.8 B | 315 A | 2001,02,05 |
| none | Platinum | 0.5 B | 298 A | 2001,02,05 |
Comparing percent of plants with psyllid injury to yield obtained from foliar trials in 2006, 2007, and 2010 (Figure A), psyllid injury correlates with most yield loss (r=.67 or r2=.45). Seed and furrow treatments, although effective in reducing psyllid injury, were not as effective in increasing yield as foliar treatments (figure not included).
Trials to Control Potato Psyllid in Scottsbluff - Seed and Furrow Applications
2000: SEED & FURROW, cv. Atlantic
Weather = normal conditions
Insect = preliminary test, no monitoring
Morphological = normal
Treatments = TopsMZ, TopsMZ Gaucho, and TopsMZ > Admire.
Data (Table 1) = Percent of plants with psyllid symptoms in late Aug decreased and yield was increased by Tops MZ Gaucho seed treatment and by Tops MZ applied to seed followed by a furrow application of Admire.
Table 1. Plants displaying psyllid injury and yield, 2000.
| Treatment | Plants with Psyllid Injury, % | Yield of > 2" Tubers cwt/acre |
| TOPS MZa | 10.4 A* | 425 B* |
| TOPS MZa & Admireb | 1.0 B | 461 AB |
| TOPS MZ Gauchoa | 0.7 B | 496 A |
* Numbers followed by the same letter are not significantly different at the 95% confidence level.
a Applied to seed pieces at 12 oz/cwt.
b Applied to furrow at 1.3 fl oz 2F/1000 lin ft
2001: SEED & FURROW, cv. Russet Norkotah
Weather = normal conditions
Insect = psyllids and leafhoppers seen in mid-July
Morphological = normal
Treatments = MaximMZ, MaximMZ + Adage, MaximMZ > Platinum, TopsMZ, TopsMZ Gaucho, and TopsMZ > Admire.
Data (Table 2) = Percent of plants with psyllid and/or leafhopper injury symptoms in late Aug decreased and yield was increased by insecticide treatments. MaximMZ, MaximMZ Adage, TopsMZ, and TopsMZ Gaucho were applied to seed pieced. Platinum and Admire were applied to the furrow at planting.
Table 2. Plants displaying insect injury and yield, 2001.
| Treatment | Plants with Psyllid Injury, % | Plants with Hopper Burn | Yield of > 2" Tubers cwt/acre |
| Maxim MZa | 30 A* | 16 A | 322 B |
| Maxim MZa + Adageb | 0.7 B | 3.5 B | 389 A |
| Maxim MZa & Platinumc | 0.7 B | 2.7 B | 368 A |
| Tops MZd | 25 A | 11 A | 325 B |
| Tops MZ Gauchod | 1.4 B | 5.9 B | 377 A |
| Tops MZd & Admiree | 0.7 B | 2.1 B | 390 A |
* Numbers followed by the same letter are not significantly different at the 95% confidence level.
a Applied to seed pieces at 8 oz/cwt.
b Added 4.5 ml to 8 oz of Maxim MZ.
c Applied to furrow at 0.55 fl oz 2SC/1000 lin ft.
d Applied to seed pieces at 12 oz/cwt.
e Applied to furrow at 1.3 fl oz 2F/1000 lin ft
2002: SEED & FURROW, cv. Russet Norkotah
Weather = high temperatures and drought conditions, and erratic soil temperatures around planting, low soil moisture at planting
Insect = fewer psyllids compared to 2000 and 2001, and appeared in mid-Aug, later than usual.
Morphological = delayed emergence and tuberization, premature senescence
Treatments = MaximMZ, MaximMZ + Adage, MaximMZ > Platinum, TopsMZ, TopsMZ Gaucho, TopsMZ + Genesis and TopsMZ > Admire.
Data (Table 3) = Percent of plants with psyllid injury symptoms in late Aug decreased and yield was increased by insecticide treatments.
MaximMZ, MaximMZ Adage, TopsMZ, and TopsMZ Gaucho were applied to seed pieced. Platinum and Admire were applied to the furrow at planting.
Table 3. Plants displaying psyllid injury and yield, 2002.
| Treatment | Plants with Psyllid Injury % | Yield of > 2" Tubers cwt/acre |
| Maxim MZa | 7.9 a* | 201 b |
| Maxim MZa + Adageb | 1.3 b | 229 a |
| Maxim MZa & Platinumc | 0.9 b | 226 ab |
| Tops MZd | 6.5 a | 205 b |
| Tops MZ Gauchod | 0 b | 243 a |
| Tops MZ + Genesise | 0.9 b | 238 a |
| Tops MZc & Admiref | 0.9 b | 235 a |
* Numbers followed by the same letter are not significantly different at the 80% confidence level.
a Applied to seed pieces at 8 oz/cwt.
b Added 4.5 ml to 8 oz of Maxim MZ.
c Applied to furrow at 0.55 fl oz 2SC/1000 lin ft.
d Applied to seed pieces at 12 oz/cwt.
e Diluted 25 ml with 75 ml water and added to cwt before adding Tops MZ.
f Applied to furrow at 1.3 fl oz 2F/1000 lin ft
2003: NO TRIAL.
2004: SEED & FURROW, cv. Russet Norkotah
weather = low temperatures in June, July & Aug with severe fluctuations, drought with low soil moisture at planting and no rain in Aug.
insect = No psyllids appeared.
morphological = delayed tuberization, premature senescence.
treatments = Maxim, Maxim + Poncho, Maxim + Cruiser, Maxim > Platinum, Maxim > Regent, TopsMZ, TopsMZ Gaucho, TopsMZ + Genesis, and TopsMZ > Admire.
data = No injury observed and no effect on yield which were very low.
Trials to Control Potato Psyllid in Scottsbluff - Foliar Applications
2005: Seed, Furrow & Foliar, cv. Atlantic
Weather = good rain in June and some in July, cold in early May
Insect = psyllids and aphids appeared in late July
Morphological = delayed planting, tuberization on time
Treatments = MaximMZ, MaximMZ + Cruiser, MaximMZ > Platinum, MaximMZ > Actara, MaximMZ > Provado, MaximMZ > BAS320.
Data (Table 4) = Percent of plants with psyllid symptoms and with aphid injury in late Aug decreased and yield was increased by insecticide treatments. Maxim MZ and Cruiser were applied to seed pieces; Platinum was applied to furrow at planting, and Actara, Provado and BAS320 was applied twice to the foliage.
Table 4. Plants displaying insect injury and yield, 2005.
| Treatment | Psyllid Yellow % plants | Calico White % plants | Aster Yellow % plants | Yield US #1 cwt/acre |
| Maxim MZa | 56 A* | 11 A | 8 A | 230 C |
| Maxim MZa + Cruiserb | 0.5 C | 6 BC | 0 D | 327 A |
| Maxim MZa & Platinumc | 0 C | 2 C | 0 D | 300 A |
| Maxim MZa & Actarad | 23 B | 3 C | 1 CD | 243 BC |
| Maxim MZa & Provadoe | 6 C | 3 BC | 3 BC | 296 AB |
| Maxim MZa & BAS320f | 25 B | 9 AB | 3 AB | 291 AB |
* Numbers followed by the same letter are not significantly different at the 95% confidence level.
a Applied to seed pieces at 8 oz/cwt.
b Added 4 ml to 8 oz of Maxim MZ.
c Applied to furrow at 0.55 fl oz 2SC/1000 lin ft.
d Applied 1.5 oz/a with X77, twice.
e Applied 3.75 fl oz 1.6F/a with X77, twice.
f Applied 4.57 fl oz/a with Penetrator Plus, twice.
Note: X77 and Penetrator Plus are surfactants.
2006: Foliar, cv. Atlantic
Weather = cooler and wetter than normal
Insect = psyllids and Colorado potato beetle appeared in Aug
Morphological = normal
Treatments = Maxim seed treatment followed by either no foliar application or by Actara or Oberon at three rates.
Data (Table 5) = Percent of plants with psyllid symptoms and with larva on leaves in late Aug decreased slightly. Yield was not affected. Maxim FS was applied to seed pieces, and Actara and Oberon were applied twice to the foliage.
Table 5. Plants displaying insect injury and yield, 2006.
| Treatment | Psyllid Yellow % plants | CPB Larva % plants | Yield US #1 cwt/acre |
| Maxima | 43 A* | 100 A | 275 b |
| Maxima & Actarab | 29 BC | 50 B | 312 ab |
| Maxima & Oberon/lowc | 31 B | 0 C | 257 b |
| Maxima & Oberon/midd | 21 C | 0 C | 312 ab |
| Maxima & Oberon/highe | 10 D | 0 C | 367 a |
* Numbers followed by the same letter are not significantly different at the 95% confidence level and those followed by same small letter are not significantly different at the 80% confidence level.
a Applied to seed pieces at 8 oz/cwt.
b Applied 1.5 oz/a with X77, twice.
c Applied 8 fl oz 2SC/a with X77, twice.
d Applied 12 fl oz 2SC/a with X77, twice.
e Applied 16 fl oz 2SC/a with X77, twice.
Note: X77 is a non-ionic surfactant, a sticker-spreader.
2007: Foliar, cv. Atlantic
Weather = drought conditions with less than 2 inch rain with irrigation total for season was over 20 inches. Record high temperatures were reported early in season with prolonged heat periods during the seaso
Insect = psyllids in Aug, lots of fleabeetles, few sick Col. potato beetles
Morphological = normal
Treatments = Maxim seed treatment followed by either no foliar application or by Actara, Oberon at three rates, Ultra at two rates, or Ultra at low rate with urea.
Data (Table 6) = Percent of plants with psyllid symptoms in mid Aug decreased slightly. Yield were low but were affected by treatment. Maxim FS was applied to seed pieces, and Actara, Oberon and Ultra were applied twice to the foliage.
Table 6. Plants displaying insect injury and yield, 2007.
| Treatment | Psyllid Yellow % plants | Yield US #1 cwt/acre |
| Maxima | 80 a* | 133 b |
| Maxima & Actarab | 48 bc | 178 a |
| Maxima & Oberon/lowc | 63 ab | 149 ab |
| Maxima & Oberon/midd | 43 bc | 161 ab |
| Maxima & Oberon/highe | 26 c | 175 a |
| Maxima & Ultra/lowf | 53 b | 138 b |
| Maxima & Ultra/low+Urg | 37 bc | 172 a |
| Maxima & Ultra/highh | 45 bc | 173 a |
* Numbers followed by the same letter are not significantly different at the 90% confidence level.
a Applied to seed pieces at 8 oz/cwt.
b Applied 1.5 oz/a with X77, twice.
c Applied 8 fl oz 2SC/a with crop oil, twice.
d Applied 12 fl oz 2SC/a with crop oil, twice.
e Applied 16 fl oz 2SC/a with crop oil, twice.
f Applied 6 fl oz 150SC/a, twice.
g Applied 6 fl oz 150SC/a with urea added at 1 qt/a, twice.
h Applied 8 fl oz 150SC/a, twice.
Note: No surfactant was added to Ultra.
2008: Foliar, cv. Atlantic
Weather = drought conditions with total of 5 inch rain for season with irrigation total was 25 inches.
Insect = no insects appeared
Morphological = normal
Treatments = Maxim seed treatment followed by either no foliar application or by Provado @ 3.75 fl oz/a, Asana @ 4.4 fl oz/a, Oberon 240SC @ 8, 12, 16 fl oz/a, Oberon @ 12 fl oz/a plus urea-ammonium nitrate (UAN) @ 3 pt/a, Movento 240SC @ 4, 5 fl oz/a with Dyne-Amic surfactant, or Movento @ 4 fl oz/a plus UAN with either Dyne-Amic or 'NIS' as an additive, HGW86 100GL @ 13.7, 20.5 fl oz/a.
Data = No insect injury was observed and no zebra chip symptom was seen in tubers; yields were good at 350 cwt/a with no effect by treatment.
2009: Foliar, cv. Atlantic
Weather = heavy rains in June with normally dry July and Aug; total rain for season was 8 inches; with irrigation, the total was 23 inches,
Insect = no psyllids appeared but large infestation of grasshoppers
Morphological = normal
Treatments = Maxim seed treatment followed by either no foliar application or by Provado @ 3.75 fl oz/a, Oberon 480SC @ 4, 6, 8 fl oz/a, Oberon @ 8 fl oz/a plus urea-ammonium nitrate (UAN) @ 3 pt/a, Movento 240SC @ 5 fl oz/a with either Agri-Dex or Dyne-Amic as surfactant, or Movento @ 5 fl oz/a plus UAN and MSA concentrate as an additive,
Data (Table 7) = Only grasshopper injury was observed. Percent of plants eaten by grasshoppers in Aug decreased. Yield were good but there was little effect by treatments. Maxim FS was applied to seed pieces, and Actara, Oberon and Movento were applied twice to the foliage.
Table 7. Plants displaying insect injury and yield, 2009.
| Treatment | Grasshopper Feeding % plants | Grasshopper Injury scale 0-5 | Yield US #1 cwt/acre |
| Maxima | 23 A* | 3.0 a | 341 |
| Maxima & Oberon/lowb | 13 AB | 1.7 ab | 355 |
| Maxima & Oberon/midc | 7 B | 1.3 b | 381 |
| Maxima & Oberon/highd | 7 B | 1.3 b | 360 |
| Maxima & Oberon/high+UANe | 6 B | 1.0 b | 357 |
| Maxima | 23 A | 1.7 a | 370 |
| Maxima & Provadof | 6 B | 1.0 ab | 395 |
| Maxima & Moventog | 4 B | 0.7 ab | 370 |
| Maxima & Moventoh | 4 B | 0.7 ab | 377 |
| Maxima & Movento+UANi | 3 B | 0.3 b | 387 |
* Numbers followed by the same capital letter are not significantly different at the 95% confidence level and those followed by same small letter are not significantly different at the 90% confidence level.
a Applied to seed pieces at 8 oz/cwt.
b Applied 4 fl oz 480SC/a with Dyne-Amic, twice.
c Applied 6 fl oz 480SC/a with Dyne-Amic, twice.
d Applied 8 fl oz 480SC/a with Dyne-Amic, twice.
e Applied 8 fl oz 480SC/a with Dyne-Amic plus UAN at 3 pt/a, twice.
f Applied 3.75 fl oz 1.6F/a with X77, twice.
g Applied 5 fl oz 240SC/a with Agri-Dex, twice.
h Applied 5 fl oz 240SC/a with Dyne-Amic, twice.
i Applied 5 fl oz 240SC/a with MSA plus UAN at 3 pt/a, twice.
2010: Foliar, cv. Atlantic
Weather = heavy rains in June with dry July and Aug; with irrigation, seasonal precipitation was 24-25 inches.
Insect = adult psyllids and nymphs appeared in early July and the nymph population was substantial in Aug. (See Figure.)
Morphological = normal
Treatments = Maxim seed treatment followed by either no foliar application or by Provado @ 3.75 fl oz/a, Oberon 480SC @ 6, 8 fl oz/a, Oberon @ 6 fl oz/a plus urea-ammonium nitrate (UAN) @ 3 pt/a, Movento 240SC @ 5 fl oz/a.
Data (Table 8) = Percent of plants with psyllid symptoms throughout Aug decreased with treatments but gradually increased during the month and into Sep. Yield were affected by psyllid. Maxim FS was applied to seed pieces, and Provado, Oberon and Movento were applied twice to the foliage.
Table 8. Plants displaying insect injury and yield, 2009.
| Treatment | Psyllid Yellow, on Aug 6 | % of plants on Aug 20 | on Sep 9 | Yield, US#1 wt/acre |
| Maxima | 14 A* | 34 A | 64 A | 161 c |
| Maxima & Provadob | 7 B | 27 A | 53 A | 192 bc |
| Maxima & Moventoc | 7 B | 6 B | 22 B | 243 a |
| Maxima & Oberon/lowd | 0 B | 4 B | 12 BC | 214 ab |
| Maxima & Oberon/low+UANe | 6 B | 6 B | 10 BC | 215 ab |
| Maxima & Oberon/highf | 2 B | 4 B | 9 C | 243 a |
* Numbers followed by the same capital letter are not significantly different at the 95% confidence level and those followed by same small letter are not significantly different at the 90% confidence level.
a Applied to seed pieces at 8 oz/cwt.
b Applied 3.75 fl oz 1.6F/a with X77, twice.
c Applied 5 fl oz 240SC/a with Dyne-Amic, twice.
d Applied 6 fl oz 480SC/a with Dyne-Amic, twice.
e Applied 6 fl oz 480SC/a with Dyne-Amic plus UAN at 3 pt/a, twice.
f Applied 8 fl oz 480SC/a with Dyne-Amic, twice.