breeding for insect resistance hessian fly in wheat a case study stephen harrison fangneng huang...
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Breeding for Insect ResistanceHESSIAN FLY IN WHEATHESSIAN FLY IN WHEAT
A case studyA case study
Stephen HarrisonStephen HarrisonFangneng HuangFangneng HuangRogers LeonardRogers Leonard
Acknowledgements: David Buntin - Dept. of Entomology – University of Georgia – Griffin CampusJohn Van Duyn - NC State University Randy Weisz – NC State
Ben Edge – Clemson University
Larvae
Puparia (flaxseed)
Hessian fly damage looks different, depending on when the wheat was infested
sometimes a wide leaf blade is a symptom. Often the wide blade has a blue-green hue.
Fly damaged plants and/or tillers
Adults
Hessian fly Mayetiola destructor
•There are 4-6 generations each year.
•A generation takes about 35 days at 75 º F, longer at cooler temperatures.
•Development occurs between 40-80 º F
1 2-3 3-4
HHessian fly Yield essian fly Yield LossLoss
Dec 2008 – Maringouin, LA
Seedling and early tiller stage:• One larva completely stunts and kills tiller /plant• Can have tremendous stand loss (> 75%)• Plants just mysteriously die
Hessian fly yield loss in winter wheatHessian fly yield loss in winter wheat
Jointing / Heading / grain fill stage:Jointing / Heading / grain fill stage:
Multiple larva per stems at jointsMultiple larva per stems at joints Stunts stemStunts stem Weaken stem cause lodging.Weaken stem cause lodging. Reduces grain filling / test weight.Reduces grain filling / test weight.
Ryegrass /winter wheat are common for food plots in southern “green fields”.
Inoculum Sources
• minimum tillage soybeans following wheat• early-planted wheat as pasture and foodplots• wheat straw for erosion control on roadbeds• volunteer wheat plants that emerge early• neighboring fields
• oats are not a host• rye and triticale are usually resistant
Winter Wheat Acreage and Losses to Winter Wheat Acreage and Losses to Hessian Fly in Georgia (1972-2007)Hessian Fly in Georgia (1972-2007)
0
200
400
600
800
1000
1200
1400
1600
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
Ha
rve
ste
d a
cre
s (
x1
00
0).
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
$ L
os
se
s
Acreage $ Losses
Hessian fly outbreak years
$28M
Effect of Spring Tillage on Hessian Effect of Spring Tillage on Hessian Fly Emergence from Wheat StubbleFly Emergence from Wheat Stubble
(From Chapin et al. 1992. J. Entomol. Sci. 27:293)(From Chapin et al. 1992. J. Entomol. Sci. 27:293)
0
5
10
15
20
25
30
Hes
sian
flie
s p
er t
rap
..
No-till Burn Disk Burn &Disk
Plow
aab
bc
c
d
The best disease or insect control method is a resistant variety
There are numerous Hessian Fly biotypes, each with a different set of resistance genes it is able to overcome.
Numerous plant resistance genes have been identified for Hessian flies. As they are deployed, new biotypes emerge.
It is important to know what biotypes are present in order to choose the right Hessian fly "resistant" variety
Some varieties have resistance mechanisms that are not detected in seedling assays but work well in the field as adult plants.
• Delayed planting date and seed-applied insecticides may work well with this type of resistance.
Hessian Fly Biotype Hessian Fly Biotype Composition in Southern Composition in Southern
Georgia (1986-2000) Georgia (1986-2000)
0%10%20%30%40%50%60%70%80%90%
100%
1986 1989 1991 1996 2000 2008
E
G
M
O
L
Other
Sources: R. Ratcliffe et al., USDA-ARS, Purdue Univ.
?
Gene GP A B C D E F G H I J K L M N OH1H2 R R R R R RH3 R R S R S S R S R R S R S S R SH5 R R R R R R R R S ? S S S S S SH6 R R R S S R S S R R R S S R S SH7H8 R S S S S R R R R ? S S S R R RH9 R R R S R R RH9H10 R R R R R R RH10 R R R RH11 R R RH12 R R R RH13 R R R R R R R R R R R R R R RH14H15 R R R RH17 R R R RH18(Marq) R R R R R RH19 R R R RH21(Hamlet) R R R R R R R R R R R R R R R RH22 R R R R R R R R R R R R R R R RH23 R R R R R R R R R R R R R R R RH24 R R R R R R R R R R R R R R R RH25 R R R R R R R R R R R R R R R RH26 R R R R R R R R R R R R R R R RH28H31Kawvale
Biotype
Adult Plant? Tolerance?
Hessian fly resistance chart
Non-efective genes??H gene Source R-S % R R-S % R R-S % R R-S % R
No gene Newton 0-23 0 0-23 0 0-21 0 0-22 0H3 Monon 0-21 0 0-23 0 0-19 0 0-22 0H5 Magnum 0-19 0 0-22 0 2-18 10 0-22 0H6 Caldwell 2-18 10 0-21 0 10-10 50 5-16 24H7H8 Seneca 0-24 0 1-22 4 0-15 0 0-16 0H9 Iris 17-3 85 23-1 96 12-7 63 21-3 88H10 J oy 8-9 47 15-8 65 12-7 60 19-6 76H11 Karen 6-9 40 9-10 47 2-18 10 1-19 5H12 Lola 15-1 94 12-0 100 14-2 88 19-1 95H13 Molly 21-0 100 22-1 96 23-0 100 18-2 90H14 921676A3-5 12-6 67 9-10 47 6-15 29 3-18 14H16 921682A4-6 0-20 0 14-6 70 10-15 40 13-9 54H17 921680D1-7 16-0 100 20-0 100 10-3 77 7-8 47H18 Marquillo 17-0 100 11-0 100 11-6 65 14-4 78H21 Hamlet 20-0 100 19-0 100 21-1 95 22-0 100H22 KS85WGRC01 13-2 87 16-1 94 18-6 75 13-1 93H23 KS89WGRC03 6-2 75 5-2 71 5-1 83 2-5 29H24 KS89WGRC6 8-0 100 10-0 100 6-0 100 10-0 100H25 PI 592732 19-0 100 20-0 100 21-0 100 18-0 100H26 KS92WGRC26 11-0 100 8-0 100 7-0 100 12-0 100H31 P921696A1-15-2-1 16-0 100 8-11 42 18-3 86 12-7 63H32 Synthetic 11-3 79 17-2 89 14-7 67 16-1 94
red indicates most effective genes against these pops.green indicates least effective genes
Iberville Iberville Pointee PointeeLewis Hurdle J arreau Rummler
2008 Hessian Fly Biotypes in Louisiana
CHEM VAR STD DT HFNONE AGS 2026 0.0 0.0 0.0NONE DYNA-GRO OGLETHORPE 0.0 0.3 0.2NONE AGS 2060 0.3 0.3 0.3NONE AGS 2055 2.3 1.7 2.0NONE PIONEER 26R61 4.3 3.0 3.7NONE APCK 5E35 4.7 3.7 4.2NONE MAGNOLIA 5.3 3.7 4.5NONE TERRAL LA482 5.7 5.3 5.5NONE USG 3555 6.0 5.7 5.8NONE DELTA KING DK9108 6.3 5.7 6.0NONE USG 3592 6.7 6.0 6.3NONE AGS 2020 6.7 6.3 6.5NONE PIONEER 26R87 6.7 6.7 6.7NONE COKER 9700 7.0 6.7 6.8NONE USG 3295 7.0 6.7 6.8NONE TERRAL LA841 7.0 7.0 7.0NONE AGS 2031 7.3 7.3 7.3NONE Coker 9553 7.7 7.7 7.7
Mean 4.9 4.5 4.7LSD10% 1.3 1.3 1.2CV% 19.0 22.0 19.0
HESSIAN FLY DATA with no insectcide seed treatment. Dec 17, 2008. Maringouin, LA. S. Harrison.
STD: 0 = no stand loss; 5 = moderate stand loss; 9 = complete stand lossDT: 0 = no dead/dying tillers; 5 = moderate; 9 = complete/100%HF: Hessian Fly Index = average of STD & DT: 0 = completely resistant; 9 = completely susceptible
Insecticides for Hessian FlyInsecticides for Hessian Fly Gaucho 600Gaucho 600
0.8 to 2.4 fl. oz. / 100 lb0.8 to 2.4 fl. oz. / 100 lb Gaucho XTGaucho XT
3.4 oz/100 lbs seed3.4 oz/100 lbs seed Raxil & Apron fungicidesRaxil & Apron fungicides Rate too low for HFRate too low for HF
Gaucho XT + Gaucho 600 Gaucho XT + Gaucho 600 @ 1 oz/100 lb seed@ 1 oz/100 lb seed
Commercial seed treaterCommercial seed treater Seed conditioner, dealerSeed conditioner, dealer
Cruiser 5FS (Wheat-Pak)Cruiser 5FS (Wheat-Pak) 1 oz/100 lb seed1 oz/100 lb seed Contains 3 fungicidesContains 3 fungicides Rate too low for HFRate too low for HF Max. 1.33 oz/100 lb seedMax. 1.33 oz/100 lb seed
Karate Z (1.92 oz/A) Karate Z (1.92 oz/A) @ 2-4 leaf stage. @ 2-4 leaf stage. @ full tiller (early to mid @ full tiller (early to mid
March)March) Suppression; Timing Suppression; Timing
difficultdifficult
VAR Cruiser None
USG 3555 0.00 0.63AGS 2060 0.00 0.75PIONEER 26R61 3.50 4.50PIONEER 26R87 6.25 5.75TERRAL LA821 6.13 6.13TERRAL LA841 5.75 6.50
MEAN 3.61 4.04
Significant at 5%
HF: Hessian Fly Index = 0 = no damage; 9 = severe damage
HESSIAN FLY DATA: Seed Treatment Comparison. Dec 17, 2008. Maringouin, LA.
Cruiser Significantly reduced Hessian Fly damage, but:• the level of control provided was not adequate• very severe damage still occurred on susceptible varieties.
Hessian Fly Management Hessian Fly Management TacticsTactics
Rotate wheat if possible. Rotate wheat if possible. Control volunteer wheat. Control volunteer wheat. Do not use susceptible wheat as cover Do not use susceptible wheat as cover
crops/wildlife plantings.crops/wildlife plantings.Conventional tillage (fall and spring).Conventional tillage (fall and spring).Plant at recommended times.Plant at recommended times.Variety selection.Variety selection.
Plant resistant varieties (if possible).Plant resistant varieties (if possible).Plant susceptible varieties ‘only’ in new fields.Plant susceptible varieties ‘only’ in new fields.
Insecticides use strategiesInsecticides use strategiesSeed treatments Seed treatments Lambda cyhalothrin - scouting for late winter Lambda cyhalothrin - scouting for late winter
suppression. suppression.
Hessian Fly – 2009 - LAHessian Fly – 2009 - LA
Any Questions???
Breeding for Resistance to Breeding for Resistance to InsectsInsects
S.A. HarrisonS.A. Harrison
Spring 2007Spring 2007
ImmunityImmunity
A variety is not consumed or injured by an A variety is not consumed or injured by an insect that is known to attack other insect that is known to attack other varieties of the same species.varieties of the same species. there are no known cases of immunity there are no known cases of immunity
to insects in maizeto insects in maize
From: Jennifer Kling Crop and Soil Science Oregon State University
Mechanisms of resistanceMechanisms of resistance NonpreferenceNonpreference ( (antixenosisantixenosis) – characteristics of the plant are ) – characteristics of the plant are
not favored by the insect for ovipositioning, feeding, or shelternot favored by the insect for ovipositioning, feeding, or shelter AntibiosisAntibiosis – feeding by the insect results in – feeding by the insect results in
reduced fecundityreduced fecundity decreased sizedecreased size abnormal lifespanabnormal lifespan increased mortalityincreased mortality
ToleranceTolerance – the plant is able to grow and reproduce, or to – the plant is able to grow and reproduce, or to repair injury despite a level of insect infestation that would repair injury despite a level of insect infestation that would damage a susceptible hostdamage a susceptible host may exert less selection pressure on the insect population to overcome may exert less selection pressure on the insect population to overcome
the resistancethe resistance not harmful to beneficial insectsnot harmful to beneficial insects
From: Jennifer Kling Crop and Soil Science Oregon State University
ResistanceResistance
• A variety may possess A variety may possess more than one mechanismmore than one mechanism of resistance of resistance– all types of resistance to stem borers in maize have been all types of resistance to stem borers in maize have been
identifiedidentified• These mechanisms of resistance are These mechanisms of resistance are controlled by different controlled by different
genetic factorsgenetic factors, but effects are interrelated, but effects are interrelated• Degree of resistance may vary from highly resistant to highly Degree of resistance may vary from highly resistant to highly
susceptiblesusceptible• It may be possible to determine experimentally which It may be possible to determine experimentally which
mechanism is involved, but the actual plant characteristic or mechanism is involved, but the actual plant characteristic or compound causing resistance has been identified in only a few compound causing resistance has been identified in only a few casescases
• Selection can be effective without knowing the specific factors Selection can be effective without knowing the specific factors responsible for resistanceresponsible for resistance
From: Jennifer Kling Crop and Soil Science Oregon State University
Pseudo-resistancePseudo-resistance
host evasionhost evasion ( (avoidanceavoidance)) – variety passes through – variety passes through susceptible phase at a time when the insect population susceptible phase at a time when the insect population is not highis not high
induced resistanceinduced resistance (1) (1) – improvement in crop – improvement in crop management reduces the damage caused by the insectmanagement reduces the damage caused by the insect increased waterincreased water fertilizer applicationfertilizer application
induced resistanceinduced resistance (2) (2) – plant’s defense system is – plant’s defense system is enhanced in response to external physical or chemical enhanced in response to external physical or chemical stimuli (may last a few days)stimuli (may last a few days)
escapeescape – occurs when level of infestation in a field is – occurs when level of infestation in a field is light or unevenly distributed light or unevenly distributed some plants in the field are not exposed to the insectsome plants in the field are not exposed to the insect
these mechanisms may be temporary, and may be these mechanisms may be temporary, and may be confused with true resistanceconfused with true resistance
From: Jennifer Kling Crop and Soil Science Oregon State University
Host plant resistance to insectsHost plant resistance to insects
Many documented cases in a wide array of crop speciesMany documented cases in a wide array of crop species Breeding programs have been successfulBreeding programs have been successful High return on dollars invested in researchHigh return on dollars invested in research Breeding for insect resistance is not as widely applied or Breeding for insect resistance is not as widely applied or
accepted as a means of pest management as breeding accepted as a means of pest management as breeding for disease resistancefor disease resistance relatively easy to control with the use of insecticidesrelatively easy to control with the use of insecticides insect-rearing programs are expensiveinsect-rearing programs are expensive development of insect-rearing and infestation techniques may development of insect-rearing and infestation techniques may
take several years; requires entomology expertisetake several years; requires entomology expertise artificial infestation may not produce the behavioral or artificial infestation may not produce the behavioral or
metabolic equivalent of an insect population in nature metabolic equivalent of an insect population in nature
From: Jennifer Kling Crop and Soil Science Oregon State University
RationaleRationale
development of insects with resistance to insecticidesdevelopment of insects with resistance to insecticides adverse effects of insecticides on natural enemies and adverse effects of insecticides on natural enemies and
biodiversitybiodiversity public awareness of health risks and environmental public awareness of health risks and environmental
contamination due to pesticide usecontamination due to pesticide use host plant resistance is usually compatible with IPMhost plant resistance is usually compatible with IPMDeveloping countriesDeveloping countries greater insect pressure in the tropicsgreater insect pressure in the tropics limited access to insecticideslimited access to insecticides potentially greater health hazardspotentially greater health hazards
inadequate farmer traininginadequate farmer training water supply may be limitedwater supply may be limited
From: Jennifer Kling Crop and Soil Science Oregon State University
Requirements for an effective Requirements for an effective resistance breeding programresistance breeding program
Multidisciplinary teamMultidisciplinary team Good crop husbandryGood crop husbandry Good field plot techniqueGood field plot technique Knowledge of the biology of the insectKnowledge of the biology of the insect
life cyclelife cycle alternate hostsalternate hosts
Genetic resourcesGenetic resources Appropriate level of insect infestationAppropriate level of insect infestation
optimum insect density:damage ratio to allow optimum insect density:damage ratio to allow greatest differences in expression of resistance and greatest differences in expression of resistance and susceptibility susceptibility
From: Jennifer Kling Crop and Soil Science Oregon State University
Measurement of resistance in Measurement of resistance in the host plantthe host plant
Direct damage to host plantDirect damage to host plant stem and ear damagestem and ear damage leaf necrosis or lesionsleaf necrosis or lesions yield reduction (protected vs unprotected)yield reduction (protected vs unprotected) rating scales are commonrating scales are common
Simulated injurySimulated injury e.g., toxic effects due to application of crude extract of e.g., toxic effects due to application of crude extract of
green bug in sorghumgreen bug in sorghum Plant characteristics associated with resistancePlant characteristics associated with resistance
morphological e.g., rind thickness in maize morphological e.g., rind thickness in maize (penetrometer score)(penetrometer score)
chemical compounds known to cause antibiosis chemical compounds known to cause antibiosis
From: Jennifer Kling Crop and Soil Science Oregon State University
Indirect measures of resistance Indirect measures of resistance in the pestin the pest
insect abundanceinsect abundance sampling nets, traps, or actual countssampling nets, traps, or actual counts
insect feeding and developmentinsect feeding and development amount of food consumed amount of food consumed duration of larval/pupal developmentduration of larval/pupal development fecundityfecundity insect survivalinsect survival weight and size of insectsweight and size of insects sex ratiosex ratio proportion of insects entering diapause proportion of insects entering diapause
From: Jennifer Kling Crop and Soil Science Oregon State University
Insect behaviorInsect behavior
Measures of antixenosisMeasures of antixenosis responses to volatile stimuli responses to volatile stimuli olfactory responsesolfactory responses
olfactometersolfactometers electroantennogramselectroantennograms electroretinogramselectroretinograms electronic feeding monitors electronic feeding monitors
From: Jennifer Kling Crop and Soil Science Oregon State University
Natural field infestationNatural field infestation
AdvantagesAdvantages no extra costno extra cost number of entries is not limitednumber of entries is not limited
DisadvantagesDisadvantages distributions in the field are not uniformdistributions in the field are not uniform infestation may be ineffective in some years, reducing progress infestation may be ineffective in some years, reducing progress
from selectionfrom selection natural enemies may cause uneven infestation and damage natural enemies may cause uneven infestation and damage
symptomssymptoms may be difficult to synchronize the lifecycle and presence of the may be difficult to synchronize the lifecycle and presence of the
pest with the susceptible growth stage of the plantpest with the susceptible growth stage of the plant May be acceptable for preliminary disease screenings, May be acceptable for preliminary disease screenings,
but artificial infestation is necessary for accurate but artificial infestation is necessary for accurate evaluationsevaluations
From: Jennifer Kling Crop and Soil Science Oregon State University
Artificial infestationArtificial infestation Requires mass rearing of the insectRequires mass rearing of the insect
on growth mediumon growth medium on suitable hoston suitable host requires space in lab or greenhouserequires space in lab or greenhouse rearing and oviposition chambers with temperature rearing and oviposition chambers with temperature
and humidity controland humidity control laboratory strains of the insect may change over timelaboratory strains of the insect may change over time
Insects are available year-round, at the right timeInsects are available year-round, at the right time Level and time of infestation can be controlledLevel and time of infestation can be controlled Field infestation is labor intensiveField infestation is labor intensive
From: Jennifer Kling Crop and Soil Science Oregon State University
Enhanced field infestationEnhanced field infestation Control natural enemiesControl natural enemies with use of selective insecticides with use of selective insecticides
or cagesor cages Spreader rowsSpreader rows (trap crops) may be used to enhance (trap crops) may be used to enhance
natural infestationnatural infestation Stagger plantingsStagger plantings throughout the season to achieve better throughout the season to achieve better
synchronization with insect life cyclesynchronization with insect life cycle ReplantReplant in the same field in the same field Late plantingsLate plantings or crops grown in the 2 or crops grown in the 2ndnd rainy season rainy season
(bimodal rainfall pattern) may have higher insect incidence(bimodal rainfall pattern) may have higher insect incidence Use hot-spotsUse hot-spots, where the insects are known to occur , where the insects are known to occur
regularly in high numbers each seasonregularly in high numbers each season Light traps, pheromone traps, and kairomone trapsLight traps, pheromone traps, and kairomone traps can be can be
used to attract natural insect populationsused to attract natural insect populations Collect insectsCollect insects in nearby fields and in nearby fields and releaserelease in test plots in test plots
From: Jennifer Kling Crop and Soil Science Oregon State University
CagingCaging under greenhouse and field conditionsunder greenhouse and field conditions maintains uniform insect pressure on the test maintains uniform insect pressure on the test
entriesentries test plants infested at the same phenological test plants infested at the same phenological
stagestage prevents insects from migrating away from the prevents insects from migrating away from the
test plantstest plants protects insects from natural enemies protects insects from natural enemies
http://www.icrisat.org/text/research/grep/homepage/grephomepage/archives/tech.htm
Stem borers in maizeStem borers in maize European corn borer (ECB) European corn borer (ECB) Ostrinia nubilalisOstrinia nubilalis (Hübner) (Hübner) Fall armyworm (FAW) Fall armyworm (FAW) Spodoptera frugiperdaSpodoptera frugiperda (Smith) (Smith) Southwestern cornborer (SWCB) Southwestern cornborer (SWCB) Diatraea grandiosella Diatraea grandiosella
(Dyar)(Dyar) Sugarcane borer (SCB) Sugarcane borer (SCB) Diatraea saccharalis Diatraea saccharalis (F)(F) Corn earworm Corn earworm HelicoverpaHelicoverpa (= (=HeliothisHeliothis) ) zeazea (Boddie) (Boddie) Asian corn borer Asian corn borer Ostrinia furnacalis Ostrinia furnacalis (Guenee)(Guenee) Pink borer Pink borer Sesamia nonagrioidesSesamia nonagrioides (Lefebvre) (Lefebvre) African speciesAfrican species African maize stalk borerAfrican maize stalk borer Busseola fusca Busseola fusca (Fuller) (Fuller) African sugarcane borerAfrican sugarcane borer Eldana saccharina Eldana saccharina (Walker)(Walker) Pink stalk borerPink stalk borer Sesamia calamistis Sesamia calamistis (Hampson) (Hampson) Spotted stem borerSpotted stem borer Chilo partellus Chilo partellus (Swinhoe) (introduced) (Swinhoe) (introduced)
From: Jennifer Kling Crop and Soil Science Oregon State University
Causal agentsCausal agents
Sesamia nonagrioides Lefebvre ‘pink borer’ ‘la sesamie’ Noctuidae, Amphipyrinae
Ostrinia nubilalis Hübner‘European corn borer’ Pyralidae, Pyraustinae
Lepidopterans
Slide courtesy Isabel Vales From: Jennifer Kling Crop and Soil Science Oregon State University
Sesamia nonagrioidesSesamia nonagrioides: : Population dynamicsPopulation dynamics
Slide courtesy Isabel Vales
Several generations per yearSeveral generations per year Yield and quality losses: up to 30% yield losses in maizeYield and quality losses: up to 30% yield losses in maize Integrated pest management neededIntegrated pest management needed
agronomic, chemical, biological, and genetic controlagronomic, chemical, biological, and genetic control
From: Jennifer Kling Crop and Soil Science Oregon State University
Field infestation techniquesField infestation techniques
Egg massesEgg masses whorl of plant (1whorl of plant (1stst generation European corn generation European corn
borer) borer) leaf sheath (leaf sheath (Sesamia calmistis, Sesamia calmistis, 22ndnd generation generation
European corn borer, European corn borer, Eldana saccharinaEldana saccharina)) agar suspended eggs delivered to silks by agar suspended eggs delivered to silks by
pressure pump (corn ear worm)pressure pump (corn ear worm)
Larvae Larvae applied to silks with a brush (corn ear worm)applied to silks with a brush (corn ear worm) mixed with cob grits and applied by bazookamixed with cob grits and applied by bazooka
From: Jennifer Kling Crop and Soil Science Oregon State University
Rating scales used for stem Rating scales used for stem borersborers
Typically from 1 (resistant) to 9 (susceptible)Typically from 1 (resistant) to 9 (susceptible) Leaf feedingLeaf feeding
size and number of lesions on leavessize and number of lesions on leaves dead hearts (growing point destroyed)dead hearts (growing point destroyed)
Stem damageStem damage stem tunnellingstem tunnelling frass on maize leaf sheaths and collarsfrass on maize leaf sheaths and collars stalk breakagestalk breakage
Ear damageEar damage cm of feeding from tipcm of feeding from tip frass on earsfrass on ears
Photos courtesy Isabel ValesFrom: Jennifer Kling Crop and Soil Science Oregon State University
Sources of resistanceSources of resistance Antiguan landraces showed high level of Antiguan landraces showed high level of
resistance to 1resistance to 1stst and 2 and 2ndnd generation ECB. Good generation ECB. Good generalized resistance to borers.generalized resistance to borers.
Zapalote chicoZapalote chico – Mexican landrace with – Mexican landrace with resistance to corn earworm (CEW)resistance to corn earworm (CEW)
Mp lines from Mississippi StateMp lines from Mississippi State CIMMYT populations with multiple borer CIMMYT populations with multiple borer
resistance:resistance: MBR subtropical populationMBR subtropical population MIRT tropical populationMIRT tropical population
Mo17 and TZi4 (tropical conversion)Mo17 and TZi4 (tropical conversion) resistant to resistant to Sesamia calamistisSesamia calamistis
From: Jennifer Kling Crop and Soil Science Oregon State University
Genetics of resistance to stem Genetics of resistance to stem borersborers
Summary of a number of studiesSummary of a number of studies polygenicpolygenic
cases of single gene resistance to cases of single gene resistance to insects are less common than for insects are less common than for disease resistance in plantsdisease resistance in plants
primarily additive gene actionprimarily additive gene action largely due to GCAlargely due to GCA
Granados and Paliwal, 2000 From: Jennifer Kling Crop and Soil Science Oregon State University
Genetics of the resistanceGenetics of the resistance Quantitative traitsQuantitative traits
Stem resistanceStem resistance Ear resistanceEar resistance Yield under infestationYield under infestation
General combining ability (GCA), specific General combining ability (GCA), specific combining ability (SCA), reciprocal effects (R) combining ability (SCA), reciprocal effects (R)
Diallel of 10 inbred lines (resistant and Diallel of 10 inbred lines (resistant and susceptible)susceptible) GCA was the most important factor for stem and GCA was the most important factor for stem and
ear traitsear traits GCA, SCA were significant for yield under GCA, SCA were significant for yield under
infestationinfestation
Butron et al. 1999; Notes from Isabel Vales
From: Jennifer Kling Crop and Soil Science Oregon State University
QTL’s for resistanceQTL’s for resistance
Insect resistance is a good candidate for Insect resistance is a good candidate for MASMAS
QTLs identified for QTLs identified for 22ndnd generation ECB in US temperate maize generation ECB in US temperate maize SWCB and AmSB in tropical maize (CIMMYT)SWCB and AmSB in tropical maize (CIMMYT)
Some QTL regions were common to both speciesSome QTL regions were common to both species Sesamia nonagrioidesSesamia nonagrioides in Spain in Spain
Morphological resistance Morphological resistance factorsfactors
Tight husksTight husks Reduced trichome density, delayed pubescence Reduced trichome density, delayed pubescence
less preferred by CEWless preferred by CEW High silica content in cellsHigh silica content in cells
imparts some resistance to ECBimparts some resistance to ECB Epidermal cell wall thicknessEpidermal cell wall thickness
highly correlated with leaf feeding damage highly correlated with leaf feeding damage by SWCB and FAWby SWCB and FAW
Others…Others…
Smith, in Mihm (ed.), 1997
AllelochemicalsAllelochemicals
Maysin (C-glycosylflavone) in maize silksMaysin (C-glycosylflavone) in maize silks first shown to inhibit growth of CEW in Zapalote first shown to inhibit growth of CEW in Zapalote
chico (Snook chico (Snook et alet al., 1993)., 1993) now known to occur in high concentration in a now known to occur in high concentration in a
number of populations and inbred linesnumber of populations and inbred lines DIMBOA in leavesDIMBOA in leaves
antibiotic effect on ECB, and to a lesser extent antibiotic effect on ECB, and to a lesser extent SWCB and FAWSWCB and FAW
Phenolic acid in maize grainPhenolic acid in maize grain associated with resistance to maize storage associated with resistance to maize storage
pestspests related to the hardness of the grainrelated to the hardness of the grain
From: Jennifer Kling Crop and Soil Science Oregon State University
Fungal interactions with stem Fungal interactions with stem borersborers
Damage to the ear by ECB and other ear Damage to the ear by ECB and other ear borers associated with increased borers associated with increased incidence of mycotoxinsincidence of mycotoxins FusariumFusarium spp. spp. Aspergillus flavusAspergillus flavus
Bt lines have been shown to have lower Bt lines have been shown to have lower levels of some mycotoxins than their non-levels of some mycotoxins than their non-Bt isogenic linesBt isogenic lines
Conventional resistance to insects may Conventional resistance to insects may also reduce levels of mycotoxinsalso reduce levels of mycotoxins
Breeding schemesBreeding schemes
Backcrossing Backcrossing ECB resistance from Cornell Composite ECB ECB resistance from Cornell Composite ECB
introgressed into elite temperate inbred linesintrogressed into elite temperate inbred lines Temperate lines with borer resistance Temperate lines with borer resistance
converted for resistance to maize streak virus converted for resistance to maize streak virus at IITAat IITA
Granados and Paliwal, 2000
From: Jennifer Kling Crop and Soil Science Oregon State University
Breeding schemesBreeding schemes Recurrent selection: IntrapopulationRecurrent selection: Intrapopulation
EPS12 - selection for EPS12 - selection for stalk tunnellingstalk tunnelling resistance (Butron resistance (Butron et al.et al. 2005) 2005) Half-sib selection for resistance to Asian stem borer in the Half-sib selection for resistance to Asian stem borer in the
PhilippinesPhilippines Full-sib family selection for resistance to Full-sib family selection for resistance to Chilo partellusChilo partellus in India in India full-sib, half-sib Sfull-sib, half-sib S11 family selection for MBR at CIMMYT family selection for MBR at CIMMYT SS11 family selection for resistance to family selection for resistance to Eldana saccharinaEldana saccharina and and Sesamia Sesamia
calamistiscalamistis at IITA at IITA SS1 1 half-sib selection for resistance to Fall armyworm (FAW-CC)half-sib selection for resistance to Fall armyworm (FAW-CC)
Recurrent selection: InterpopulationRecurrent selection: Interpopulation EPS20 (Reid) and EPS21 (non-Reid) EPS20 (Reid) and EPS21 (non-Reid) –– selection for yield under selection for yield under
infestationinfestation TransformationTransformation
Transgenic varieties produce Bt toxin for resistance to ECB and fall Transgenic varieties produce Bt toxin for resistance to ECB and fall armywormarmyworm
From: Jennifer Kling Crop and Soil Science Oregon State University
Bt cornBt corn Bt corn contains the gene from a soil bacterium Bt corn contains the gene from a soil bacterium Bacillus Bacillus
thuringiensisthuringiensis Produces a toxin that protects against the European corn borer and Produces a toxin that protects against the European corn borer and
other insectsother insects EPA approved Bt corn for use in 1995 (Cry1Ab, Cry1Ac)EPA approved Bt corn for use in 1995 (Cry1Ab, Cry1Ac) Production peaked at about 26% of total acreage in 1999Production peaked at about 26% of total acreage in 1999 In 2000, EPA requires that farmers growing Bt corn must plant at In 2000, EPA requires that farmers growing Bt corn must plant at
least 20% of their total corn acreage to a non-Bt variety least 20% of their total corn acreage to a non-Bt variety ‘‘StarLink’ version of Bt (Cry9C protein) was approved only for StarLink’ version of Bt (Cry9C protein) was approved only for
animal feed in 1999 – concerns over possible allergenicityanimal feed in 1999 – concerns over possible allergenicity Problem – grain dealers do not maintain separate stocks of corn for Problem – grain dealers do not maintain separate stocks of corn for
feed and food, nor for GMO vs conventional hybridsfeed and food, nor for GMO vs conventional hybrids Aventis removed ‘StarLink’ from the market in 2000, after it was Aventis removed ‘StarLink’ from the market in 2000, after it was
found in human food suppliesfound in human food supplies
From: Jennifer Kling Crop and Soil Science Oregon State University
MAS for insect resistanceMAS for insect resistance
traditional approaches have been successful, traditional approaches have been successful, but progress is slow and sufficient genetic but progress is slow and sufficient genetic variation is not found in some species variation is not found in some species
wild relatives are valuable sources of insect wild relatives are valuable sources of insect resistance for many crop species; MAS could resistance for many crop species; MAS could reduce linkage dragreduce linkage drag
permits pyramiding of resistance genes; may permits pyramiding of resistance genes; may be particularly useful for developing be particularly useful for developing populations with resistance to multiple species populations with resistance to multiple species of insectsof insects
Yencho et al., 2000 From: Jennifer Kling Crop and Soil Science Oregon State University
Lessons from stem borers in Lessons from stem borers in maizemaize
Knowledge of the causal agent population dynamics, Knowledge of the causal agent population dynamics, the host plant life cycle and plant-pathogen the host plant life cycle and plant-pathogen interactions is very importantinteractions is very important
Artificial infestation is needed for accurate screeningArtificial infestation is needed for accurate screening Polygenic inheritance, GCA, and additive gene action Polygenic inheritance, GCA, and additive gene action
are most importantare most important Recurrent selection has been effective in a number of Recurrent selection has been effective in a number of
populationspopulations Direct measurements of damage on the host plant Direct measurements of damage on the host plant
are most effective selection criteriaare most effective selection criteria MAS can be used to complement conventional MAS can be used to complement conventional
breedingbreeding
From: Jennifer Kling Crop and Soil Science Oregon State University
Insect Resistance to Insect Resistance to Bacillus thuringiensis (B.t.)Bacillus thuringiensis (B.t.)
1970 Introduction of 1970 Introduction of B.t.B.t. products products 1985 First reports of 1985 First reports of B.t.B.t. resistance resistance
McGaughey, 1985McGaughey, 1985
Additional reports of Additional reports of B.t.B.t. resistance resistance Tabashnik, Cushing, Finson, and Johnson, 1990Tabashnik, Cushing, Finson, and Johnson, 1990 Tabashnik, 1994Tabashnik, 1994 Lui, Tabashnik, Dennehy, Patin, and Bartlett, Lui, Tabashnik, Dennehy, Patin, and Bartlett,
19991999
Carol Pilcher Marlin Rice Jon Tollefson Department of Entomology Iowa State UniversityCarol Pilcher Marlin Rice Jon Tollefson Department of Entomology Iowa State University
Insect-Protection TraitsInsect-Protection Traits
YieldGardYieldGard® ® Corn BorerCorn Borer Registered 1997Registered 1997
HerculexHerculex™™ I I Registered 2002Registered 2002
YieldGardYieldGard®® Rootworm Rootworm Registered 2003Registered 2003
YieldGardYieldGard®® Plus Plus Registered 2003Registered 2003
Carol Pilcher Marlin Rice Jon Tollefson Department of Entomology Iowa State UniversityCarol Pilcher Marlin Rice Jon Tollefson Department of Entomology Iowa State University
Key Component of Insect Key Component of Insect Resistance Management is Resistance Management is
RefugeRefuge
Refuge is a block or strip of a crop Refuge is a block or strip of a crop that does not contain the technology that does not contain the technology traittrait e.g., a block or strip of corn that does e.g., a block or strip of corn that does
not contain the not contain the B.t.B.t. technology for technology for control of the corn rootwormcontrol of the corn rootworm
Refuge StrategyRefuge StrategyGoal of non-B.t. refuge is to maintain susceptible insects
in the population that can mate with rare resistant insects and produce susceptible insects in next
generation
= susceptible to B.t. corn = resistant to B.t. corn
Non-B.t. RefugeB.t. Crop
Growers Must Sign a Growers Must Sign a Technology Agreement and Technology Agreement and
Agree to Follow the Agree to Follow the Insect Resistance Insect Resistance
Management RequirementsManagement Requirements European corn borer insect-protected traitsEuropean corn borer insect-protected traits Corn rootworm insect-protected traitsCorn rootworm insect-protected traits
IRM Requirements IRM Requirements European Corn Borer Insect-European Corn Borer Insect-
Protection TraitsProtection Traits Growers must plant at least a 20% non-Growers must plant at least a 20% non-
B.t.B.t. refuge refuge Growers must plant Growers must plant B.t.B.t. corn within ½ corn within ½
mile of a refuge, preferably within ¼ mile of a refuge, preferably within ¼ milemile
Strip-planted refuges must be at least Strip-planted refuges must be at least 4 rows wide and preferably 6 rows wide4 rows wide and preferably 6 rows wide
IRM Requirements IRM Requirements European Corn Borer Insect-European Corn Borer Insect-
Protection TraitsProtection Traits
Refuges can be treated with Refuges can be treated with insecticides if economic thresholds insecticides if economic thresholds are reached for one or more target are reached for one or more target insectsinsects
Microbial Microbial B.t.B.t. insecticides must not insecticides must not be applied to refugebe applied to refuge
Insect Resistance Insect Resistance ManagementManagement
Refuge possibilities for Refuge possibilities for YieldGardYieldGard®® Corn Borer and Corn Borer and
HerculexHerculex™™ I I
B.t. corn
Refuge
Perimeter Block Split Planter
Perimeter RefugePerimeter Refuge
Advantages:Advantages: 20% refuge can be 20% refuge can be
treated if neededtreated if needed Can harvest Can harvest B.t.B.t. and and
non-non-B.t.B.t. separately separately Minimize number of Minimize number of
seed changesseed changes Limitations:Limitations:
May need to match May need to match herbicide toleranceherbicide tolerance
Block RefugeBlock Refuge Advantages:Advantages:
Good mixing of insectsGood mixing of insects 20% refuge can be 20% refuge can be
treated if neededtreated if needed Can harvest Can harvest B.t.B.t. and and
non-non-B.t.B.t. separately separately Limitations:Limitations:
More time changing More time changing seed & cleaning seed & cleaning hoppershoppers
May need to match May need to match herbicide toleranceherbicide tolerance Non-B.t. corn
0
5
10
15
20
% I
NF
ES
TA
TIO
N
1970 1980 1990YEAR
LOSS OF THE H-5 GENE
NO-RESISTANCE
H-5
0
20
40
60
80
% H
-5 P
LA
NT
ED
1970 1980 1990YEAR
DEPLOYMENT OF H-5 WHEAT
Figure 1b
0
5
10
15
% I
NF
ES
TA
TIO
N
1960 70 80 1990YEAR
LOSS OF THE H-6 GENE
NO-RESISTANCE
H-6
0
20
40
60
80
% H
-6 P
LA
NT
ED
1960 70 80 1990YEAR
DEPLOYMENT OF H-6 WHEAT
Figure 1c
Percentage of Bt Corn and Bt Cotton Planted in the US
0
5
10
15
20
25
30
35
40
45
95 96 97 98 99 0O O1 O2 O3
Bt Corn
BT Cotton
% o
f to
tal a
cres
Source: USDA
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