Bloom Period Mngement of Lygus bug in Alflf Seed J.D. Brbour University of Idho Prm Reserch nd Extension Center
Lygus biology & life cycle Serious pest of lflf seed nd other seed crops Overwinter s dults (lte Oct. to Nov. in ID) Plnt crowns, litter, & debris Fields, field mrgins Nturl res Become ctive nd mte in spring (~April)
Lygus biology & life cycle Femles insert eggs in plnt tissue Htch in 1-4 weeks Immtures (nymphs) Develop through 5 instrs in 1 to 2 months 1 distinct nd 2 to 3 overlpping genertions per yer in SW Idho
Lygus biology & life cycle Prefer to feed on reproductive plnt prts Flowers, seeds Prefer reproductive stge lflf to nerly ny other plnt Lygus + lflf grown for seed = the perfect storm
Lygus dmge Lygus bugs feed using needle-like mouthprts, injecting slivry enzymes into plnt tissue Two types of dmge Physicl dmge from probing Chemicl dmge from digestive enzymes Cuses most dmge Kills plnt tissue Cuses deformed growth Dmge cused by dults nd nymphs
Lygus dmge Feed on developing flower buds, flowers, & immture pods Drying (blsting) of flower buds Flower, seed pod drop Reduction in seed yield possible with hevy infesttions
Lygus dmge to lflf seed Most dmge from feeding on immture seeds in developing pods Most (> 7%) dmge cused by 4 th nd 5 th instrs nd dults Dmge is to green seed: stylets cn t penetrte hrd seed Without mngement, losses of 5% to nerly 1% re possible
Lygus mngement Mnged lrgely with insecticides A number of insecticides lbeled for lygus control Brod spectrum OP s, crbmtes, pyrethroids Severl lower-risk insecticides vilble Usefulness of vilble compounds limited by Efficcy nd resistnce mngement issues Toxicity to beneficil insects Nturl enemies, but especilly Pollintors: ID-lflf lefcutting bee (ALCB) Need for effective, bee-sfe insecticides
213 Lygus Efficcy Trils in Alflf Seed Tril 1: Pesticide rottions for lygus control in bloom period lflf seed Tril 2: Assil 3WP (cetomiprid; 27) Belef (flonicmid: 27) Rimon (novlurn: 26) Trnsform SG (sulfoxflor: 214?) Wrrior Grndevo for lygus control in bloom period lflf seed
Tril 2: Grndevo during bloom Grndevo (Mrrone Bio Innovtions) Insecticide clss: microbil/ bio-insecticide, Chromobcerium subtsuge nd fermenttion products IRAC resistnce group: unknown Mode of ction: unknown, likely complex Route: ingestion, repellency, reduced fecundity Systemic in plnt: no Insect stges ffected: dult nd immture insects, especilly erly instrs. Activity spectrum: brod spectrum, chewing nd sucking insects
Tril 1: Insecticides for Bloom Period Rottion Assil 7WP (United Phosphorus, Inc.) Insecticide clss: neonicotinoid IRAC resistnce group: 4A Mode of ction: nerve poison. Mimics cetocholine nd binds to nicotinic cetocholine receptors: over stimultion of nerve signls t synpse Route: ingestion nd contct Systemic in plnt: Yes, especilly folir pplictions Insect stges ffected: dult nd immture insects, especilly erly instrs Activity spectrum: Sucking insects (phids, plnt bugs), some ctivity on chewing insects
Tril 1: Insecticides for Bloom Period Rottion Trnsform WG (Dow AgroSciences, LLC) Insecticide clss: neonicotinoid IRAC resistnce group: 4C, only member of this subgroup Mode of ction: nerve poison. Mimics cetocholine nd binds to nicotinic cetocholine receptors: over stimultion of nerve signls t synpse Route: ingestion Systemic in plnt: trnslminr Insect stges ffected: dult nd immture insects, especilly erly instrs. Activity spectrum: sucking insects only (phids, plnt bugs)
Tril 1: Insecticides for Bloom Period Rottion BeLef 5SG (FMC Corp) Insecticide clss: pyridinecrboxmide, feeding inhibitor IRAC resistnce group: 9C Mode of ction: nerve poison. Blocks pre-synptic potssium chnnels resulting in uncontrolled cetocholine relese t synpse Route: ingestion Systemic in plnt: trnslminr Insect stges ffected: dult nd immture insects, especilly erly instrs. Activity spectrum: sucking insects only (phids, plnt bugs). Slow cting
Tril 1: Insecticides for Bloom Period Rottion Rimon.83EC (Chemtur Corp.) Insecticide clss: benzoylphenylure, insect growth regultor (CSI/IGR) IRAC resistnce group: 15 Mode of ction: disrupts cuticle (chiton) synthesis, prevents molting (growth from one insect stge (instr) to the next) Route: ingestion nd contct Systemic in plnt: No Insect stges ffected: immtures, especilly erly instrs. Some ctivity ginst eggs. No dult ctivity Activity spectrum: brod, especilly chewing insects, but some ctivity on sucking insects (phids, plnt bugs, etc.). Slow cting. Toxic to bee lrve
Residul toxicity (RT) of insecticides to Tril gols dult lflf lefcutting bees Compre % mortlity of dult ALCB exposed to field-wethered pesticide residues on lflf folige treted with stndrd (Cpture) nd untreted folige Pesticides cusing mortlity of 25% or less (RT 25 ) on 8 hour residues likely re sfe to pply lte evenings with little bee hzrd RT 25 of 2 hours or less: likely re sfe to pply erly mornings
ALCB Residul toxicity tril Tril methods Experimentl design 4 rows x 3ft Rndomized complete block Tretments: insecticides t lbeled rtes 4 replictions Appliction Folir spry, CO 2 bckpck spryer hnd held boom 3 gl/ @ 3 psi
Tril methods Smpling ALCB Residul toxicity tril Hnd collected folige from plots t 2, 8, 24, 48 nd 96 hours fter tretment (~ 4 cm 3 ) Collect live bees from domiciles in grower fields Confine bees on field-wethered folige (2-3/rep) Determine mortlity fter 24 hrs. Sttisticl nlysis Anlysis of Vrince of % mortlity djusted for control mortlity
RT 25 (hrs) for selected insecticides to dult beneficil insects Pesticide Beneficil Insect ALCB Bigeyed bug Dmsel bug Minute pirte bug Assil 4 4 4 ~96 Belef 2 2 2 2 Cpture >96 >96 >96 ~96 Crzol 4 96 48 >96 Grndevo*???? Rimon 4 4 4 4 Trnsform 2??? RT 25 2: pply when bees re not forging RT 25 8: pply during lte evening or night *Grndevo cuses little or no bee mortlity but my repel bees for severl dys
Rimon Impct on Bee Return Lbeled for bloom period lygus bug control in lflf seed Effective lygus control Sfe to dult ALCB Toxic to ALCB lrve Cn reduce lflf lefcutting bee (ALCB) return Directly, by contct of eggs nd lrve with contminted provisions nd nesting mteril Indirectly, through dult ingestion of Rimon in nectr or on lef mteril
Percentge Mortlity Rimon Impct on Bee Return Rimon is directly toxic to ALCB eggs on dosed provisions in the lbortory (Hodgson et l. 211) 28 Rimon provision dosing experiment > 9 % mortlity of ALCB eggs on Rimontreted provisions 1 9 8 7 6 5 X=field rte of Rimon: 12 oz/cre in 3 gl/cre 4 Blnk H 2 O 1/2x 1x 2x 1x Tretment
Percentge Mortlity Rimon Impct on Bee Return Rimon lso is indirectly toxic to ALCB eggs vi dult consumption of Rimon in the lbortory (Hodgson et l. 211) Adults fed Rimon dosed sucrose ly high percentge of unvible eggs 1 8 6 4 2 28 Rimon dult dosing experiment 1% Sugr-H2 + Rimon Tretment 16.17% Sugr-H 2 O
% live lrve % Pollen Blls Rimon Impct on Bee Return Results of lb studies hve been confirmed in the field, but effects re not s strong Lower % live lrve nd higher % pollen blls in Rimontreted fields 7 6 5 4 3 2 1 b 29 21 bc c b 7 6 5 4 3 2 1 b 29 21 b bc c Rimon Tretment
211 Rimon Bee Return Study Impct of Rimon ppliction timing on bee return: will lter ppliction reduce negtive impcts? Three bloom period tretments Rimon pplied erly: s soon s bees ctively flying Rimon pplied lte: three weeks lter No Rimon control: grower stndrd prctice Rimon pplictions Single ppliction per tretment @ high rte (12 oz) in 2-3 gp (mde by growers) Mde regrdless of lygus numbers
Totl cells Rimon Impct on Bee Return Impct of ppliction timing on totl number of cells per smple 9 8 7 6 5 4 3 2 1 Rimon Erly Rimon Lte No Rimon Tretment
% Pollen blls Rimon Impct on Bee Return Impct of ppliction timing on men percentge pollen blls per smple 6 5 4 3 2 b b 1 Rimon Erly Rimon Lte No Rimon Tretment
% Live lrve Rimon Impct on Bee Return Impct of ppliction timing on men percentge live lrve per smple 6 5 4 3 2 1 Rimon Erly Rimon Lte No Rimon Tretment
213 Idho Lygus pesticide trils Pesticide tril methods.1 cre plots (22 ft x 22 ft) Rndomized complete block: 4 replictes 3 gp @ 32 psi (trctor-drwn boom spryer) 3 sweeps/plot pre-trt nd 1 week intervls fter trt Lygus bug nymphs: erly (1-3) nd lte (4,5) instrs Aphids (pe phid, blue nd spotted lflf phids) Lygus predtors (hemipterns) nd ldy beetles Anlyzed by ANOVA: split plot in time
Idho pesticide efficcy trils Tril 1. Insecticide rottions for bloom period lygus control No. Tretment i IRAC group Rte 1 Trnsform BeLef Rimon 2 BeLef Trnsform Rimon 3 Belef Trnsform Wrrior 4 Belef Assil Trnsform sulfoxflor flonicmid novluron lmbd cyhlothrin cetomiprid 4C, neonicotinoid 9C, feeding blocker 15, Chiton synthesis inhib. 4A, neonicotinoid 5 UTC n/ n/ n/ Applictions t 2 week intervls 1.5 oz 2.8 oz 12 oz 2.8 oz 1.5 oz 12 oz 2.8 oz 1.5 oz 1.9 oz 2.8 oz 2.3 oz 1.5 oz
Number per Sweep Bloom-Period Insecticide Tril 1 Men number of Lygus dults per smple on ech smple dy nd over ll smple dys on treted nd untreted plots 3 25 2 15 1 5 7/12 7/26 6/28 3 7 14 21 28 35 42 49 12 1 8 6 4 2 b b b b Dys fter Tretment Bf/Al/Tm Bf/Tm/Rn Bf/Tm/Wr Tretment Tm/Bf/Rn UTC
Number per Sweep Bloom-Period Insecticide Tril 1 Men number of smll Lygus nymphs per sweep on ech smple dy nd over ll smple dys on treted nd untreted plots 6 5 4 3 2 1 6/28 7/12 7/26 3 7 14 21 28 35 42 49 Dys fter Tretment Bf/Al/Tm Bf/Tm/Rn Bf/Tm/Wr 2 16 12 8 4 b b b Tretment b Tm/Bf/Rn UTC
Number per Sweep Bloom-Period Insecticide Tril 1 Men number of lrge Lygus nymphs per sweep on ech smple dy nd over ll smple dys on treted nd untreted plots 1 8 6 4 6/28 7/12 7/26 25 2 15 1 bc bc b c 2 5 3 7 14 21 28 35 42 49 Dys fter Tretment Tretment Bf/Al/Tm Bf/Tm/Rn Bf/Tm/Wr Tm/Bf/Rn UTC
Number per Sweep Men number of pe nd blue lflf phids per sweep on ech dy nd over ll smple dys on treted nd untreted plots 16 14 12 1 8 6 4 2 6/28 Bloom-Period Insecticide Tril 1 7/12 7/26 3 7 14 21 28 35 42 49 Dys fter Tretment Bf/Al/Tm Bf/Tm/Rn Bf/Tm/Wr 35 3 25 2 15 1 5 b b b Tretment b Tm/Bf/Rn UTC
Number per Sweep Bloom-Period Insecticide Tril 1 Men number of spotted lflf phids on ech smple dy nd over ll smple dys on treted nd untreted plots 25 2 15 1 5 6/28 7/12 7/26 3 7 14 21 28 35 42 49 Dys fter Tretment Bf/Al/Tm Bf/Tm/Rn Bf/Tm/Wr 8 6 4 2 b b b b Tretment Tm/Bf/Rn UTC
Number per Sweep Bloom-Period Insecticide Tril 1 Men number of lygus predtors per sweep on ech smple dy nd over ll smple dys on treted nd untreted plots 12 1 8 6 4 2 6/28 7/12 7/26 3 7 14 21 28 35 42 49 Dys fter Tretment Bf/Al/Tm Bf/Tm/Rn Bf/Tm/Wr 8 6 4 2 b b b b Tretment Tm/Bf/Rn UTC
Number per Sweep Bloom-Period Insecticide Tril 1 Men number of ldy beetles per sweep on ech smple dy nd over ll smple dys on treted nd untreted plots 1..5. 6/28 7/12 7/26 3 7 14 21 28 35 42 49 Dys fter Tretment Bf/Al/Tm Bf/Tm/Rn Bf/Tm/Wr.12.8.4 Tretment Tm/Bf/Rn UTC
Idho pesticide efficcy trils Tril 2. Grndevo for bloom period lygus control No. Tretment i IRAC group Rte 1 Grndevo Chromobcterium subtsuge strin PRAA4-1 nd fermenttion products unknown 2 lb. 2 Grndevo 3 lb. 5 UTC n/ n/ n/ 2 Grndevo pplictions/ tretment, 2 week prt
Number per Sweep Bloom-Period Insecticide Tril 2 Men number of Lygus dults per smple on ech smple dy nd over ll smple dys on treted nd untreted plots 3 25 2 15 1 5 7/12 6/28 3 7 14 21 28 35 42 49 12 1 8 6 4 2 GE2 GE3 UTC Dys fter Tretment Tretment GE2 GE3 UTC
Number per Sweep Men number of smll Lygus nymphs per sweep on ech smple dy nd over ll smple dys on treted nd untreted plots 7 6 5 4 3 2 1 6/28 Bloom-Period Insecticide Tril 2 7/12 3 7 14 21 28 35 42 49 Dys fter Tretment 25 2 15 1 5 GE2 GE3 UTC Tretment GE2 GE3 UTC
Number per Sweep 1 8 6 4 2 Bloom-Period Insecticide Tril 2 Men number of lrge Lygus nymphs per sweep on ech smple dy nd over ll smple dys on treted nd untreted plots 6/28 7/12 3 7 14 21 28 35 42 49 Dys fter Tretment 25 2 15 1 5 GE2 GE3 UTC Tretment b GE2 GE3 UTC
Number per Sweep 16 14 12 1 8 6 4 2 Bloom-Period Insecticide Tril 2 Men number of pe nd blue lflf phids per sweep on ech dy nd over ll smple dys on treted nd untreted plots 6/28 7/12 3 7 14 21 28 35 42 49 Dys fter Tretment 4 3 2 1 GE2 GE3 UTC Tretment GE2 GE3 UTC
Number per Sweep Bloom-Period Insecticide Tril 2 Men number of spotted lflf phids on ech smple dy nd over ll smple dys on treted nd untreted plots 4 3 2 1 6/28 7/12 1 8 6 4 2 3 7 14 21 28 35 42 49 Dys fter Tretment GE2 GE3 UTC Tretment GE2 GE3 UTC
Number per Sweep Bloom-Period Insecticide Tril 2 Men number of lygus predtors per sweep on ech smple dy nd over ll smple dys on treted nd untreted plots 2 18 15 13 1 8 5 3 7/12 6/28 3 7 14 21 28 35 42 49 Dys fter Tretment 8 6 4 2 GE2 GE3 UTC Tretment GE2 GE3 UTC
Number per Sweep Bloom-Period Insecticide Tril 2 Men number of ldy beetles per sweep on ech smple dy nd over ll smple dys on treted nd untreted plots 1. 6/28 7/12.1.5.5. 3 7 14 21 28 35 42 49 GE2 GE3 UTC Dys fter Tretment Tretment GE2 GE3 UTC
Tril 1 Conclusions Lower nos. of smll nd lrge Lygus nymphs nd phids on ll treted plots: Trnsform BeLef Rimon provided best control Belef Trnsform Wrrior lest control No mjor impct on Lygus predtors from ny rottion tretment Tril 2 Grndevo provided no control of Lygus dults, nymphs, or phids t the 2 or 3 lb rtes
Thnks to: WASGA/USDA-ARS Logn Bee lb For finncil support ID Grower/coopertors For ccess to fields nd bees nd mking pplictions for the Rimon tril Dirylnd Seed (Lynn Nichols), Pioneer Hi- Bred (Brd Chmbers) For their help orgnizing the Rimon tril Chemtur Corp. Dow AgroSciences For providing mterils for the Rimon tril Noemi Fernndez, Kren Brbour nd Rebecc Blnscet For their help conducting this work
211 Rimon Bee Return Study Field selection Four blocks of three fields ech Two blocks mnged by one grower Erly Control Two blocks mnged by different growers Lte Rimon nd control tretments ssigned rndomly to fields where possible Blocks mnged by sme grower, similr trts ner ech other
Proportion m mortlity Residul Toxicity of Pesticides to Adult Beneficil Insects 1..75.5 Assil ALCB 1..75.5 Rimon.25. 1..75.5.25. 2 8 24 48 96 Belef BEB MPB DB.25. 2 8 24 48 96 1..4.2. 2 8 24 48 96 2 8 24 48 96.8.6 Hours fter tretment metflumizone