Potato Leafhopper-Resistant Alfalfa-Potato Leafhopper-Resistant Alfalfa-2002 Update2002 Update

J. L. HansenJ. L. Hansen11, J. Keith Waldron, J. Keith Waldron22, and D.R. Viands, and D.R. Viands11

11Dept. Of Plant Breeding; Dept. Of Plant Breeding; 22NYS IPM ProgramNYS IPM Program - Livestock & Field Crops- Livestock & Field Crops

Cornell University - Ithaca, NYCornell University - Ithaca, NYCAIC Virtual Meeting, 7/2003

Potato Leafhopper in AlfalfaPotato Leafhopper in Alfalfa

Potato leafhopper (PLH), is the most damaging insect pest of Potato leafhopper (PLH), is the most damaging insect pest of alfalfa,alfalfa, Medicago sativa Medicago sativa L., in midwestern and eastern states L., in midwestern and eastern states (Manglitz and Ratcliffe, 1988).(Manglitz and Ratcliffe, 1988).

MigrationMigration

PLH over-winter in southern regions of the US and migrate PLH over-winter in southern regions of the US and migrate northward on spring storms. PLH populations can be expected on northward on spring storms. PLH populations can be expected on alfalfa in New York from mid-June through August. Newly alfalfa in New York from mid-June through August. Newly planted seedings are at highest risk of damage.planted seedings are at highest risk of damage.

Potato Leafhopper Resistant AlfalfaPotato Leafhopper Resistant AlfalfaThe PLH resistance (glandular hairs) was developed The PLH resistance (glandular hairs) was developed from a wild species of alfalfa and transferred into from a wild species of alfalfa and transferred into conventional alfalfa through traditional plant conventional alfalfa through traditional plant breeding techniquesbreeding techniques

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Potato leafhopper resistant (dark green plots) and susceptible (light Potato leafhopper resistant (dark green plots) and susceptible (light green plots) alfalfa in a spring-seeded plot trial prior to first harvest. green plots) alfalfa in a spring-seeded plot trial prior to first harvest.

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Plot trials comparing PLH-resistant and susceptible alfalfa cultivars andexperimentals have been planted in New York every year since 1996.

Results from trials planted in 1997 through 2000 are in: J. Hansen et al, Crop Science 42:1155-1163

PLH Resistant Alfalfa – PLH Resistant Alfalfa – Summary of Results from 1997-Summary of Results from 1997-

20002000PLH-resistant alfalfa cultivars and experimentalsPLH-resistant alfalfa cultivars and experimentals• sustained significantly less visible PLH damage, sustained significantly less visible PLH damage, • supported fewer nymphs and adult PLH, supported fewer nymphs and adult PLH, • had higher crude protein concentration, and had higher crude protein concentration, and • matured earlier matured earlier than susceptible cultivars and experimentals.than susceptible cultivars and experimentals.

PLH Resistant Alfalfa – PLH Resistant Alfalfa – Summary of Results from 1997-Summary of Results from 1997-

20002000• Early generation PLH-resistant cultivars did Early generation PLH-resistant cultivars did not provide complete and adequate not provide complete and adequate protection against yield loss due to PLH.protection against yield loss due to PLH.

• However, PLH-resistant cultivars and However, PLH-resistant cultivars and experimentals consistently yielded more than experimentals consistently yielded more than PLH-susceptible cultivars at the first harvest PLH-susceptible cultivars at the first harvest of the first production year, following severe of the first production year, following severe PLH damage in the seeding year.PLH damage in the seeding year.

PLH Resistant Alfalfa – PLH Resistant Alfalfa – Conclusions from 1997-Conclusions from 1997-

20002000• When insecticides were not used to control PLH, first When insecticides were not used to control PLH, first generation PLH-resistant cultivars provided benefits generation PLH-resistant cultivars provided benefits such as higher percent crude protein, less hopperburn, such as higher percent crude protein, less hopperburn, and higher forage yield at first harvest in the year and higher forage yield at first harvest in the year following severe PLH damage during the seeding year. following severe PLH damage during the seeding year.

• However, until total season yields of PLH-resistant However, until total season yields of PLH-resistant alfalfa cultivars equal or exceed the yields of alfalfa cultivars equal or exceed the yields of conventional alfalfa cultivars, PLH-resistant alfalfa conventional alfalfa cultivars, PLH-resistant alfalfa cultivars will likely represent only a small to moderate cultivars will likely represent only a small to moderate percentage of total alfalfa seed sales.percentage of total alfalfa seed sales.

PLH Resistant Alfalfa – 2002PLH Resistant Alfalfa – 2002

In 2002, four trials of PLH-resistant and susceptible In 2002, four trials of PLH-resistant and susceptible alfalfa experimentals and cultivars were harvested. alfalfa experimentals and cultivars were harvested.

The following slides summarize data from no-insecticide The following slides summarize data from no-insecticide trials harvested in 2002.trials harvested in 2002.

The objective of this study was to compare later-The objective of this study was to compare later-generation PLH-resistant alfalfa cultivars and generation PLH-resistant alfalfa cultivars and experimentals (planted in 2001 and 2002) with early-experimentals (planted in 2001 and 2002) with early-generation PLH-resistant alfalfa cultivars and generation PLH-resistant alfalfa cultivars and experimentals (planted in 1999 and 2000) for yield and experimentals (planted in 1999 and 2000) for yield and PLH damage.PLH damage.

Trial Cultivars and ExperimentalsTrial Cultivars and Experimentals

• 54H69 – 199954H69 – 1999• 53H81 – 199953H81 – 1999• DK121 HG – 1999DK121 HG – 1999• 4R37 – 1999, 20004R37 – 1999, 2000• DK131 HG – 1999DK131 HG – 1999• ABT 227 LH – 1999ABT 227 LH – 1999• Freedom – 1999Freedom – 1999• Clean Sweep 1000 – 1999Clean Sweep 1000 – 1999• 3A10 – 20003A10 – 2000• ZH 9840 H – 2000ZH 9840 H – 2000• ZH 9841 H – 2000ZH 9841 H – 2000• Seedway LH 3000 – 2001, 2002Seedway LH 3000 – 2001, 2002• Pegasus – 2001, 2002Pegasus – 2001, 2002• 54H91 – 200254H91 – 2002• HYTEST 340 PLH - 2002HYTEST 340 PLH - 2002

• Trophy – 1999Trophy – 1999• 5312 – 1999, 2000, 2001, 20025312 – 1999, 2000, 2001, 2002• Cimarron SR – 1999Cimarron SR – 1999• 53Q60 – 199953Q60 – 1999• Oneida VR – 1999, 2000, 2001, 2002Oneida VR – 1999, 2000, 2001, 2002• Vernal – 1999, 2000, 2001, 2002Vernal – 1999, 2000, 2001, 2002• Alfagraze – 1999Alfagraze – 1999• HayGrazer – 2000HayGrazer – 2000• Du 299 – 2000Du 299 – 2000• Key – 2000Key – 2000• Paragon BR – 2001Paragon BR – 2001• DU 200 – 2001DU 200 – 2001• GPVL44 – 2002GPVL44 – 2002• CK2000 - 2002CK2000 - 2002

PLH-Resistant, Year PlantedPLH-Resistant, Year Planted PLH-Susceptible, Year PlantedPLH-Susceptible, Year Planted

PLH Resistant Alfalfa – PLH Resistant Alfalfa – 20022002

CaveatsCaveats • Data over trials are confounded by field, Data over trials are confounded by field,

year of planting, and entries.year of planting, and entries.

• A small number of later-generation PLH- A small number of later-generation PLH- resistant cultivars have been tested.resistant cultivars have been tested.

Number of PLH-Resistant alfalfa cultivars Number of PLH-Resistant alfalfa cultivars entered in Cornell Forage Yield Testing entered in Cornell Forage Yield Testing

Program 1997-2002 dropped after release of Program 1997-2002 dropped after release of first generation cultivars.first generation cultivars.

No. of PLH-No. of PLH- % of Total % of Total YearYear Resistant EntriesResistant Entries No. of EntriesNo. of Entries19971997 88 252519981998 1313 373719991999 44 131320002000 2 experimentals2 experimentals 5520012001 2 cultivars2 cultivars 101020022002 2 cultivars2 cultivars 1010

PLH Resistant Alfalfa – 2002 PLH Resistant Alfalfa – 2002 Data for each of four trials are presented Data for each of four trials are presented

in the next four slides.in the next four slides.In Production year trials:In Production year trials:• Early generation PLH-resistant cultivars and Early generation PLH-resistant cultivars and

experimentals had an average PLH damage score experimentals had an average PLH damage score of 3.4.of 3.4.

• Later generation PLH-resistant cultivars had an Later generation PLH-resistant cultivars had an average PLH damage score of 1.4.average PLH damage score of 1.4.

PLH damage score: PLH damage score: 1=almost no damage; 5=severe PLH damage1=almost no damage; 5=severe PLH damage

1999 Trial harvested in 2002 – early generation PLH-1999 Trial harvested in 2002 – early generation PLH-resistant cultivars and experimentalsresistant cultivars and experimentals

Yield Data – 2002Yield Data – 2002TotalTotal % of % of PLH PLH

17Jun17Jun 5Aug5Aug 17Sep17Sep SeasonSeason Trial Trial DamageDamage % Stand% Stand- - - - - tons/acre dry matter - - -- - - tons/acre dry matter - - - Average Average 8/5/20028/5/2002

10/4/200210/4/2002 Avg. of 8 Res. Avg. of 8 Res. 2.702.70 1.841.84 0.570.57 5.105.10 99 99 3.5 3.5 88.8 88.8EntriesEntriesAvg. of 7 Sus.Avg. of 7 Sus. 2.872.87 1.661.66 0.630.63 5.165.16 101 101 5.0 5.0 91.1 91.1EntriesEntries

Res. Vs Sus.Res. Vs Sus. -0.18**-0.18** +0.18**+0.18**-0.06**-0.06** -0.05 ns-0.05 ns -1.4**-1.4** -2.4**-2.4***, ** = statistically significant at P<0.05 and 0.01 respectively; ns=not statistically significant.*, ** = statistically significant at P<0.05 and 0.01 respectively; ns=not statistically significant.PLH damage score: 1=none 5=severe.PLH damage score: 1=none 5=severe.

PLH-resistant trial entries had significantly higher forage yield than PLH-resistant trial entries had significantly higher forage yield than PLH-susceptible entries at second harvest, and had lower forage yieldPLH-susceptible entries at second harvest, and had lower forage yield at first and third harvest.at first and third harvest.

2000 Trial harvested in 2002 – early generation PLH-2000 Trial harvested in 2002 – early generation PLH-resistant experimentalsresistant experimentals

Yield Data – 2002Yield Data – 2002TotalTotal % of % of PLH PLH

18Jun18Jun 9Aug9Aug 19Sep19Sep SeasonSeason Trial Trial DamageDamage No. NymphsNo. Nymphs- - - - - tons/acre dry matter - - -- - - tons/acre dry matter - - - Average Average 8/8/20028/8/2002

8/8/20028/8/2002 Avg. of 4 Res. Avg. of 4 Res. 3.683.68 2.312.31 0.670.67 6.686.68 104 104 3.4 3.4 28 28EntriesEntriesAvg. of 6 Sus.Avg. of 6 Sus. 3.693.69 2.022.02 0.650.65 6.366.36 99 99 4.8 4.8 36 36EntriesEntries

Res. Vs Sus.Res. Vs Sus. -0.01ns-0.01ns +0.29**+0.29**+0.02ns+0.02ns +0.32**+0.32** -1.4**-1.4** -8ns-8ns*, ** = statistically significant at P<0.05 and 0.01 respectively; ns=not statistically significant.*, ** = statistically significant at P<0.05 and 0.01 respectively; ns=not statistically significant.PLH damage score: 1=none 5=severe. No. of nymphs per 10 stems averaged over 3 replications.PLH damage score: 1=none 5=severe. No. of nymphs per 10 stems averaged over 3 replications.

PLH-resistant trial entries had significantly higher forage yield than PLH-resistant trial entries had significantly higher forage yield than PLH-susceptible entries at second harvest, but had comparable forage yieldPLH-susceptible entries at second harvest, but had comparable forage yieldat first and third harvests.at first and third harvests.

2001 Trial harvested in 2002 – later generation PLH-2001 Trial harvested in 2002 – later generation PLH-resistant cultivarsresistant cultivars

Yield Data – 2002Yield Data – 2002TotalTotal % of % of PLH PLH No. PLHNo. PLH

24Jun24Jun 8Aug8Aug 7Sep7Sep SeasonSeason Trial Trial DamageDamage per 5 sweepsper 5 sweeps- - - - - tons/acre dry matter - - -- - - tons/acre dry matter - - - Average Average 8/2/20028/2/2002

7/30/20027/30/2002 Avg. of 2 Res. Avg. of 2 Res. 3.053.05 1.601.60 0.760.76 5.405.40 105 105 1.4 1.4 7 7EntriesEntriesAvg. of 5 Sus.Avg. of 5 Sus. 2.692.69 1.651.65 0.640.64 4.984.98 96 96 4.8 4.8 75 75EntriesEntries

Res. Vs Sus.Res. Vs Sus. +0.36**+0.36**-0.05ns-0.05ns +0.12**+0.12** +0.42**+0.42** -3.4**-3.4** -68**-68***, ** = statistically significant at P<0.05 and 0.01 respectively; ns=not statistically significant.*, ** = statistically significant at P<0.05 and 0.01 respectively; ns=not statistically significant.PLH damage score: 1=none 5=severe. PLH damage score: 1=none 5=severe.

PLH-resistant trial entries had significantly higher total season forage yield PLH-resistant trial entries had significantly higher total season forage yield than PLH-susceptible entries as a result of higher first harvest yield after severethan PLH-susceptible entries as a result of higher first harvest yield after severePLH damage in seeding year.PLH damage in seeding year.

2002 Trial harvested in 2002 – later generation PLH-2002 Trial harvested in 2002 – later generation PLH-resistant cultivarsresistant cultivars

Yield Data – 2002Yield Data – 2002TotalTotal % of% of PLH PLH

21Jul21Jul 5Sep5Sep SeasonSeason TrialTrial Damage Damage % Stand% Stand- - - tons/acre dry matter - -- tons/acre dry matter - - AverageAverage 7/21/20027/21/2002

9/24/20029/24/2002 Avg. of 4 Res. Avg. of 4 Res. 0.490.49 0.560.56 1.061.06 132132 3.2 3.2 97.1 97.1EntriesEntriesAvg. of 5 Sus.Avg. of 5 Sus. 0.170.17 0.410.41 0.580.58 7373 5.0 5.0 94.7 94.7EntriesEntries

Res. Vs Sus.Res. Vs Sus. +0.32**+0.32** +0.16**+0.16** +0.48**+0.48** -1.8**-1.8** +2.4ns+2.4ns*, ** = statistically significant at P<0.05 and 0.01 respectively; ns=not statistically significant.*, ** = statistically significant at P<0.05 and 0.01 respectively; ns=not statistically significant.PLH damage score: 1=none 5=severe. PLH damage score: 1=none 5=severe.

PLH-resistant trial entries had significantly higher total season forage yield PLH-resistant trial entries had significantly higher total season forage yield than PLH-susceptible entries in the seeding year.than PLH-susceptible entries in the seeding year.

PLH Resistant Alfalfa – PLH Resistant Alfalfa – Trends and Observations from Trends and Observations from

20022002• Although only two later-generation PLH-resistant Although only two later-generation PLH-resistant

cultivars were available for testing, in 2002 these cultivars were available for testing, in 2002 these cultivars were clearly superior in resistance and forage cultivars were clearly superior in resistance and forage yield to early-generation PLH-resistant cultivars. yield to early-generation PLH-resistant cultivars.

• Although more PLH-resistant cultivars need to be Although more PLH-resistant cultivars need to be tested for more production years, it seems likely that tested for more production years, it seems likely that PLH-resistant cultivars on the market now are PLH-resistant cultivars on the market now are comparable in forage yield to conventional cultivars.comparable in forage yield to conventional cultivars.

PLH Resistant Alfalfa – PLH Resistant Alfalfa – Trends and Observations from Trends and Observations from

20022002• Crop monitoring is Crop monitoring is still recommended still recommended to collect crop and pest status to collect crop and pest status information on which to base sound management decisions. information on which to base sound management decisions.

• PLH-resistant cultivars do not generally need to be sprayed to control PLH-resistant cultivars do not generally need to be sprayed to control PLH with the exception of very high PLH populations during the PLH with the exception of very high PLH populations during the seeding year. seeding year. • Economic thresholds adjusted for managing PLH in PLH- resistant alfalfa are Economic thresholds adjusted for managing PLH in PLH- resistant alfalfa are

not currently available.not currently available.

• Seeding year PLH-resistance improvements are needed. Seeding year PLH-resistance improvements are needed.

• Producers should not hesitate to try planting these later-generation Producers should not hesitate to try planting these later-generation PLH-resistant cultivars.PLH-resistant cultivars.

PLH Resistant Alfalfa – PLH Resistant Alfalfa – UNEXPLAINABLE Trends and ObservationsUNEXPLAINABLE Trends and Observations

• Visual differences in yield between resistant and Visual differences in yield between resistant and susceptible cultivars at times did not translate into susceptible cultivars at times did not translate into yield differences in tons per acre dry matter.yield differences in tons per acre dry matter.

• Pioneer 5312, a susceptible cultivar used as a check in Pioneer 5312, a susceptible cultivar used as a check in all four trials, had yield comparable to resistant all four trials, had yield comparable to resistant cultivars in spite of heavy PLH damage in the three cultivars in spite of heavy PLH damage in the three production year trials (105% of total season average in production year trials (105% of total season average in 1999, 109% of total season average in 2000, 102% of 1999, 109% of total season average in 2000, 102% of total season average in 2001).total season average in 2001).

J. Keith WaldronJ. Keith WaldronNew York State Integrated Pest Management Program New York State Integrated Pest Management Program Livestock and Field Crops IPMLivestock and Field Crops IPMNYS Agricultural Experiment StationNYS Agricultural Experiment Station630 W. North St., Geneva, NY 14456 630 W. North St., Geneva, NY 14456 jkw5@cornell.edujkw5@cornell.edu

Julie HansenJulie HansenDepartment of Plant BreedingDepartment of Plant BreedingForage Breeding ProjectForage Breeding Project101 A Love Lab101 A Love LabCornell UniversityCornell UniversityIthaca, NY 14853Ithaca, NY 14853jlh17@cornell.edujlh17@cornell.edu

For Further Information on this Project Contact:For Further Information on this Project Contact:

New York State New York State Integrated Pest Management ProgramIntegrated Pest Management Programhttp://www.nysipm.cornell.eduhttp://www.nysipm.cornell.edu

Forage Breeding Project at Cornell UniversityForage Breeding Project at Cornell Universitywww.plbr.cornell.edu/pbbweb/foragetest

ReferenceReferencess

Hansen, J.L., J.E. Miller-Garvin, J.K. Waldron, and D.R. Hansen, J.L., J.E. Miller-Garvin, J.K. Waldron, and D.R. Viands. 2002. Comparison of potato leafhopper-resistant and Viands. 2002. Comparison of potato leafhopper-resistant and susceptible alfalfa in New York. Crop Sci. 42:1155-1163.susceptible alfalfa in New York. Crop Sci. 42:1155-1163.

Manglitz, G.R., and R.H. Ratcliffe. 1988. Insects and Mites. Manglitz, G.R., and R.H. Ratcliffe. 1988. Insects and Mites. InIn A.A. Hanson et al. (ed.) Alfalfa and alfalfa improvement. A.A. Hanson et al. (ed.) Alfalfa and alfalfa improvement. Agronomy 29:671-704.Agronomy 29:671-704.

McCaslin, M., and D. Miller. 1998. Potato leafhopper McCaslin, M., and D. Miller. 1998. Potato leafhopper resistance. resistance. InIn C.C. Fox et al. (ed.) Standard tests to C.C. Fox et al. (ed.) Standard tests to characterize alfalfa cultivars. North Amer. Alfalfa Improv. characterize alfalfa cultivars. North Amer. Alfalfa Improv. Conf., Beltsville, MD. p. I-7.Conf., Beltsville, MD. p. I-7.