Resistance of eight species of ash trees to emerald ash borer and their mechanisms

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1 Amerin Journl of Agriulture nd Forestry 214; 2(6): Pulished online Deemer 29, 214 ( doi: /j.jf ISSN: (Print); ISSN: (Online) Resistne of eight speies of sh trees to emerld sh orer nd their mehnisms Shixing Zong 1, Jinqing Lin 2, To Wng 3, Youqing Luo 1, * 1 Key Lortory of Beijing for the Control of Forest Pests, Beijing Forestry University, Beijing 1 83, Chin 2 Ao Yng Eology nd Agroforestry Limited Compny, Jingsu , Chin 3 Mentougou Forestry Sttion, Beijing 12 3, Chin Emil ddress: youqingl@yhoo.n (Youqing Luo) To ite this rtile: Shixing Zong, Jinqing Lin, To Wng, Youqing Luo. Resistne of Eight Speies of Ash Trees to Emerld Ash Borer nd their Mehnisms. Amerin Journl of Agriulture nd Forestry. Vol. 2, No. 6, 214, pp doi: /j.jf Astrt: Ash tree, Frxinus (Oleee), is fine speies of timer, shelter nd seni tree used for fforesttion in Chin. Emerld sh orer (EAB), Agrilus plnipennis Firmire, n importnt trunk orer of sh trees, hve used gret dmge to sh trees in Chin, the United Sttes, Cnd nd other ountries. First, dult EAB lys eggs in the rk revies, then the newly hthed lrve feed on the superfiil lyers of the rk, nd enter the xylem when pprohing mturity, using gret dmge. Therefore, rk is n importnt lotion for the dult oviposition, egg development nd lrvl feeding of EAB. In order to understnd the resistne of different speies of sh trees nd their mehnisms, eight sh trees with vrying degrees of resistne to EAB were hosen to further investigte the morphologil hrteristis of the rk, ntomil struture of the tissue, min nutrients nd seondry metolites. The following results were oserved: (1) The resistne of different tree speies to EAB ws not orrelted with the rk olor, ut ws inversely proportionl to rk thikness, roughness, lentiel size, nd omptness. The thiker, rougher nd more ompt the rk ws, the lrger the lentiels were, nd in turn the greter the EAB-indued dmge ws. (2) In the ntomil struture of the rk tissues, the vessel size, wood ell numer, wood ell re nd stone ell numer were shown to e the most importnt resistne ftors, mong whih vessel re nd wood ell re were oth negtively orrelted with inset resistne, nd stone ell numer nd wood ell numer were positively orrelted. (3) Among the min nutrients nd seondry metolites, polyphenols, solule sugrs, reduing sugrs nd flvonoids were shown to e the most importnt resistne ftors, the ontents of whih in with high resistne were generlly higher thn those in suseptile. These results provide theoretil sis nd prtil guidne for reveling the resistne of different speies of sh trees to EAB, nd seleting suitle inset resistnt tree speies. Keywords: Emerld Ash Borer, Ash Tree, Brk, Resistne Mehnism 1. Introdution The emerld sh orer (EAB), Agrilus plnipennis Firmire speies of Agrilus (Coleopter: Buprestide) (Jedned, 1994; Hk et l., 22), is devstting trunk orer of sh trees. Its lrve feed on xylem nd phloem, etween whih n "S"-shped tunnel is reted, thus utting off the onduting tissues of the trunk, resulting in redued tree vigor nd eventul tree deth. As signifint trunk orers of sh trees, EAB gretly hrm the sh trees of Lioning, Shndong, Tinjin nd other lotions throughout Chin, using extreme eonomi losses. EAB were first disovered in Mihign, USA in 22, fter whih it spred to 13 sttes of the northestern USA, s well s Ontrio nd Quee of southestern Cnd in 21 (Kthleen et l., 213; Mrshll et l., 21; Wei Xi, 24; Zho Tonghi, 25). In Chin, the host plnts of EAB minly inlude velvet sh (Frxinus velutin), red sh (F. pennsylvni) nd white sh (F. merin) (Zho Tonghi et l., 25; Wei Xi et l., 24), ll of whih re importnt greening whih were imported from North Ameri to Chin (Herms et l., 24; Anulewiz et l., 27; Zho Tonghi, 25). Plnts re le to void nd endure dmge used y the pests, nd restore their originl funtions. Under similr environmentl onditions, the level of resistne vries widely mong different speies or vrieties of the sme plnt. This feture of the plnt is generlly determined y the

2 Amerin Journl of Agriulture nd Forestry 214; 2(6): iohemil or morphologil hrteristis of the plnts. Although plnts ontin the nutrients tht pests require, it is diffiult for pests to otin or use due to their hrteristis, nd they will not produe hrmful effets fter eing used. During their long-term evolution, plnts hve estlished vrious externl morphologil hrteristis nd internl tissue strutures whih my e used to prevent pest invsion. These slight hnges in morphology my hnge the pltility of herivorous insets, thus ffeting the ehvior, growth nd development of the pests (Seung et l, 25; Bosu nd Wgner, 28; Rghu, et l., 24; Etges nd Ahrens, 21; Blleni et l., 23). After suffering, plnts will generte series of hemil modifitions, nd form mehnisms for pest tolerne nd inset resistne. These hemil sustnes inlude nutrients, seondry metolites nd voltile seondry sustnes, mong whih nutrients nd seondry metolites re the mjor inset-resistnt hemils, nd hve different soures, ntures, nd tions in pest defense. Suh intertion onstitutes the mehnisms of hemil defense ginst pests in the nturl environment (Co Bing, 24). Pest resistne of plnts is preonditioned mehnism, whih my e used to resist the pressure of nturl seletion used y pests, nd inrese the opportunities for plnts to survive nd prosper. The pest resistne of different plnts nd different vrieties of the sme plnt is of gret signifine for seleting exellent ultivrs nd understnding the mehnisms of dmged. Adult EAB first lys eggs in the rk revies, then the newly hthed lrve feed on the superfiil lyers of the rk, nd enter the xylem fter pprohing mturity, using gret hrm. Therefore, rk is the min lotion of dult oviposition, egg development nd lrvl feeding for EAB. At present, the EAB-resistne mehnisms of the rk of different sh trees hs yet to e reported. In order to understnd the fetures of the externl morphology nd internl ntomil struture of the rk of different EAB-resistnt, s well s the differenes mong nutrients nd seondry metolites, eight speies of sh trees with different resistne mehnisms were hosen in this systemti study, thus providing theoretil sis for determining the resistne mehnisms of the different speies, nd seleting pproprite inset resistnt. 2. Mterils nd Methods 2.1. Test Smples From August to Otoer, 29, eight sh with different EAB resistne levels were seleted from the Beijing Botnil Grden, Chin. Among them were high resistne, inluding F. hinensis, F. rhynhophyll nd F. pltypod; low resistne speies, inluding F. mndshuri nd F. exelsior; nd suseptile, inluding F. velutin, F. pennsylvni nd F. merin (Zho Tonghi et l., 25; MFrlne et l., 25; Anulewiz et l., 27). F. mndshuri nd F. exelsior were 3-4 yers old, nd the others pproximtely 15 yers Reserh Methods Smpling Methods From the different prts of eh speies, three three-yer-old rnhes were hosen to perform lose oservtions of the morphologil hrteristis of their rks. Then, from the middle of eh rnh, rnh segment 2 m in length nd out 2 m in dimeter ws severed, nd pled in vil filled with FAA sttionry liquid for seling nd storge, to oserve the internl ntomil strutures. Finlly, the rk of eh rnh rk ws stripped off for determintion of their nutrients nd seondry metolites Determintion Methods Brk Struture Brk thikness ws mesured using vernier liper. Brk olor, roughness, omptness nd lentiel size were visully oserved using the ontrst method Internl Antomil Struture First, fter following series of steps inluding fixtion, extrtion, softening, sliing, stining, dehydrtion, re-stining, olor seprtion, nd trnsprentizing, the slies were seled with neutrl gum nd pled in dry speimen oxes to omplete the smple preprtion (Wng Zhizheng, 21). Then, under n Olympus mirosope, mirometer ws used to mesure the internl ntomil fetures of the smples, inluding four hrteristis of vessels, wood rys, wood ells nd stone ell wll thikness, eh of whih ontined different ftors (Tle 2). The smples were oserved under 1 4 mgnifition; the numer of vessels, rys, wood ells nd stone ells were oserved within n re of 1 3 mm 2 ; the mesured vlue of eh ftor ws the men vlue of the four fields of vision Nutrients nd Seondry Metolites Solule protein ontent ws determined with the Coomssie rillint lue method, totl sugr ontent with 3,5-dinitrosliyli id, totl solule sugr ontent with nthrone olorimetry, tnnin ontent with vnillin olorimetry; totl solule phenol ontent with Folin olorimetry, nd flvonoids with rutin olorimetry (Li Hesheng, 2; Wu Shuqing et l., 2) Sttistil Anlysis of Dt All the test dt were nlyzed using SPSS 12. softwre with LSD (lest signifint differene), nd nlysis of vrine nd Dunn's multiple omprisons. In ddition, when oserving the internl ntomil strutures, the oserved four hrteristi vlues of ll ftors nd inset resistne of eh of the were used for orreltion nlysis. With seril regression nd stepwise regression, the most pproprite ftors, s well s those relted to inset resistne level, were determined suessively. At the sme

3 34 Shixing Zong et l.: Resistne of Eight Speies of Ash Trees to Emerld Ash Borer nd their Mehnisms time, the inset resistne level ws ssigned for ll the tree speies, s shown y.1 for high resistne speies,.5 for low resistne speies, nd.8 for suseptile speies, in order to further determine the reltionship etween ll of the ftors nd inset resistne. 3. Results 3.1. Morphologil Chrteristis of Brk The morphologil hrteristis of the rks of the different re shown in Tle 1. There ws no signifint differene shown for rk olor mong the tree speies with inset resistne, showing its irrelevne to inset resistne. By multiple omprisons nd nlysis of vrine, it ws shown tht the rk thikness of suseptile ws signifintly more thn tht of other tree speies (Fig. 1); in ddition, the rk roughness, omptness nd lentiel size were inversely proportionl to resistne, i.e. the rougher nd more ompt the rk nd the lrger the lentiels were, the greter the EAB-indued hrm ws. Brk thikness/mm Fig. 1. Vrine nlysis of the rk thikness of the eight sh Tle 1. Morphologil hrteristis of the rk of the eight sh Tree speies Brk thikness/mm Brk olor Roughness Comptness Lentiel size High resistne Low resistne Suseptile tree speies F. hinensis 1.3±.162 Gry rown Smooth Loose Smll F. rhynhophyll.89±.242 Celdon Reltively smooth Reltively loose Smll F. pltypod.94±.72 Gry rown Reltively smooth Reltively ompt Reltively smll F. mndshuri.68±.53 Celdon Reltively smooth Compt Reltively smll F. exolsior.9±.92 Celdon Smooth Compt Reltively smll F. merin 1.69±.371 Gry rown Rough Compt Lrge F. pennsylvnl 1.74±.31 Gry rown Rough Compt Lrge F. velutin 1.96±.411 Gry rown Rough Compt Lrge Note: different letters signify signifint differene (p<.5) Internl Antomil Struture of Brk The internl ntomil hrteristis of the different tree speies re shown in Tle 2. All dt were used to estlish the retrogression eqution of inset resistne: y 1 = x x x x x x x 7 -.6x x x x x x x x 15. The oeffiient of determintion is shown y R 2 = Tle 2. Chrteristis of ntomil struture of the eight sh Tree speies Vessels Rys Numer=x 1 Rdius=x 2 Thikness=x 3 Are=x 4 Numer=x 5 Width=x 6 Are=x 7 High resistne Low resistne Suseptile tree speies F. hinensis F. rhynhophyll F. pltypod F. mndshuri F. exolsior F. merin F. pennsylvnl F. velutin

4 Amerin Journl of Agriulture nd Forestry 214; 2(6): Tle 2. Chrteristis of ntomil struture of the eight sh (ontinued) Tree speies High resistne Low resistne Suseptile wood ells Numer=x 8 Rdius=x 9 Wll thikness=x 1 Stone ells Are=x 11 Numer=x 12 Rdius=x 13 Wll thikness=x 14 F. hinensis F. rhynhophyll F. pltypod F. mndshuri F. exolsior F. merin F. pennsylvnl F. velutin Are=x 15 Note: Are is represented y mm 2. Rdius, thikness, width nd wll thikness re represented y µm. Due to the low orreltion within n entire series of ftors, the ftors my not e interdependent mong eh other. In order to void dt multiollinerity, vriles hving signifint effets on the dependent vriles re inluded, while those with no signifint effets on the dependent vriles re exluded. Finlly, through further stepwise regression nlysis, vessel size, wood ell re, wood ell numer nd stone ell numer were determined s the most importnt ftors ffeting inset resistne. These four influentil ftors were used for nlysis of vrine, nd the results re shown in Figure 2. The vessel re of the suseptile, i.e. F. pennsylvnl nd F. velutin, ws signifintly higher thn tht of the inset resistnt. Vessel re ws positively orrelted with inset resistne i.e. the lrger the vessel ws, the more suseptile the trees were, nd the less effetive the inset resistne ws. The stone ell numers of F. hinensis, F. mndshuri nd F. exelsior were signifintly lower thn those of the other. The overll regression results showed the higher the stone ell numer ws, the less suseptile the trees were, nd thus the more effetive the inset resistne ws. However, there ws no signifint differene etween the suseptile trees, F. pennsylvnl nd F. velutin, nd the resistnt trees, F. rhynhophyll nd F. pltypod. Wood ell re ws oserved to e mximum in the suseptile trees, F. pennsylvnl nd F. velutin nd resistnt tree F. pltypod, moderte in F. rhynhophyll nd F. mndshuri, nd minimum in F. exelsior, F. merin nd F. hinensis. The overll trend showed tht the wood ell re ws positively orrelted with inset resistne, i.e. the lrger the wood ell re ws, the more suseptile the trees were, nd thus the less effetive the inset resistne ws. The wood ell numers of high resistne tree F. hinensis nd low resistne tree F. exelsior were signifintly higher thn those of the other. The overll trend showed tht the wood ell numer ws negtively orrelted with inset resistne, i.e. the lrger the wood ell numer ws, the less suseptile the trees were, nd thus the more effetive the inset resistne ws. Vessel re/mm 2 No. of stone ells/numer No. of wood ells/mm

5 36 Shixing Zong et l.: Resistne of Eight Speies of Ash Trees to Emerld Ash Borer nd their Mehnisms No. of wood ells/numer Nutrients nd Seondry Metolites of Brk The nutrients nd seondry metolites of the different re shown in Tle 3. Seril retrogression ws used to estlish the reltionship etween ontents nd inset resistne: y 1 = x x x x x x 6. The oeffiient of determintion ws shown y R 2 =.42. Fig. 2. Vrine nlysis of the different ftors of the eight sh Tle 3. Contents of mjor nutrients nd seondry metolites of rk in the eight sh Tree speies Protein= x 1 Solule sugrs= x 2 Reduing sugrs= x 3 Tnninx 4 polyphenols= x 5 flvonoids= x 6 High resistne Low resistne Suseptile Note: The unit is represented y mg/g. F. hinensis F. rhynhophyll F. pltypod F. mndshuri F. exolsior F. merin F. pennsylvnl F. velutin Due to the low orreltion within n entire series of ftors, the ftors my not e interdependent mong eh other. In order to void dt multiollinerity, vriles with signifint effets on the dependent vriles were inluded, while those with no signifint effets on the dependent vriles were exluded. Through further stepwise regression nlysis, polyphenols, solule sugrs, reduing sugrs nd flvonoids were finlly determined s the most importnt ftors ffeting inset resistne. These four influentil ftors were used for nlysis of vrine, nd the results re shown in Figure 3. The ontents of polyphenols in F. hinensis, F. rhynhophyll nd F. exelsior were signifintly higher thn those in the other. In generl, the ontent of polyphenols ws negtively orrelted with inset resistne, i.e. the lrger the ontent of polyphenols ws, the less suseptile the trees were, nd thus the more effetive the inset resistne ws. Although solule sugr entered the model during retrogression, the differenes in the ontents of polyphenols mong the were not signifint. Multiple omprisons showed tht the ontent of reduing sugrs in F.hinensis ws signifintly higher thn those in F. rhynhophyll nd F. pennsylvnl, whih hd signifintly higher ontents thn other. The ontent of reduing sugrs ws negtively orrelted with inset resistne, i.e. the lrger the ontent of reduing sugrs ws, the less suseptile the trees were, nd thus the more effetive the inset resistne ws. The ontents of flvonoids in F.hinensis nd F. exelsior were signifintly higher thn those in the other, i.e. the lrger the ontent of flvonoids ws, the less suseptile the trees were, nd thus the more effetive the inset resistne ws. Content of solule sugrs/mg/g Content of polyphenols/mg/g

6 Amerin Journl of Agriulture nd Forestry 214; 2(6): Content of reduingsugrs/mg/g Content of flvonoids/mg/g Fig. 3. Vrine nlysis of min nutrients nd seondry metolites of the eight sh 4. Disussion 4.1. Morphologil Chrteristis of Brk EAB dmge ws not shown to e ssoited with rk olor, ut rther with lentiel size, roughness, omptness nd revies. The lrger the rk thikness nd lentiel size were, the greter the EAB-indued hrm ws, nd thus the more serious the inset hrm ws. The min resons for this were tht dult EAB feeds on leves to replenish nutrients, nd lrge lentiel size nd high roughness re fvorle to dult dhesion nd lrve storge (Li Huiping et l., 24). The reltionship etween rk omptness nd EAB hrm ws not evident. However, fter EAB dmge, the rk ws esily peeled off, minly due to the ft tht lrve used hrm t the junture of the phloem nd xylem. The rk revie size ws positively orrelted with EAB dmge, i.e. the greter the revie ws, the greter the hrm ws, whih ws due to the ft tht dult EAB lid eggs minly in the rk revies. The greter the revie ws, the greter the egg numer held in the revies ws, thus llowing the eggs to e esily loted y nturl enemies Internl Antomil Struture The internl ntomil struture of rk vried mong the. The vessel re, stone ell numer, wood ell numer nd wood ell re were min ftors ffeting inset resistne for the ; this differed from previous reserh findings whih stted tht the inset resistne of poplr trees ws ssoited with vessel density, wood ry width, wood ell rdius nd stone ell thikness (Li Huiping et l., 24; Liu Jingln et l., 1999; Yng Xueyn et l., 1992). The min reson for this ws tht, despite the differenes in vessel numer mong the, the fitting effet ws more suitle nd the orreltion ws higher fter the vessel re, rther thn the vessel numer, ws used. All ftors of wood rys did not enter during stepwise regression, ut insted hd ollinerity with other ftors, nd were repled y other ftors. The stone ell thikness ws originlly quite thin nd hd little differene mong the, nd ws sujet to identl error in the oservtion room. Using the stone ell numer insted of the stone ell thikness during retrogression my etter reflet the fetures of the stone ells. With the exeption of vessel re, the reltionships mong the remining ftors etween inset resistnt nd suseptile were inonsistent, showing inomplete funtionl reltionships. This signifies tht lthough ll the showed ertin overll trends, the differenes etween inset resistnt nd suseptile tree speies were not evident during nlysis of vrine, possily due to the ft tht ll of the ftors were not interdependent, ut interting, thus resulting in the resistne of the tree speies Nutrients nd Seondry Metolites Plnts my only e fed on nd hrmed y some herivorous insets fter otining nutrients of ertin types nd ontent (Qin Junde, 1995). After plnts hve een hrmed y the pests, some nutrients show orresponding hnges, suh s inresed gluose ontent nd deresed inset resistne (Hung Jinshui, 1993). In ddition, the ontents of solule sugrs, totl mino ids nd essentil mino ids hve ertin effets on the inset resistne (Li Jidong, 27). The hnges of solule sugrs nd reduing sugrs in the rk of the eight simply refleted the hnge trends. It ws found during the regression of nutrients nd seondry metolites of the eight tht single speies is not ple of simulting the inset resistne of plnts ompletely. Although polyphenols showed the gretest orreltion, the orreltion oeffiient ws only Furthermore, lthough solule sugrs hd insignifint differenes mong the speies, solule sugrs with reduing sugrs entered the model during the seond regression, nd the orreltion oeffiient rehed.8437, gret inrese, thus inditing tht in terms of plnt resistne to pests, the tions mong ll ontents were not independent, ut mutul. Over their long-term evolution, omplex interting reltionship etween plnts nd pests hs een estlished, s shown y the ft tht plnts hve diret defense retion in the wound site fter inset feeding, nd insets my lso resist or dpt to plnt defense through numer of methods (Kessler et l., 24; Ge Feng, 211). The resistne of Frxinus spp. to Agrilus plnipennis Firmire is influened y vrious ftors, ll of whih re mutully restrined, mutully promoting nd jointly determined for inset

7 38 Shixing Zong et l.: Resistne of Eight Speies of Ash Trees to Emerld Ash Borer nd their Mehnisms resistne. In the present study, the morphologil hrteristis of rk, s well s ntomil struture of tissues, nutrients, seondry metolites nd other ftors were shown to e relted ftors. The voltile sustnes of, ntomil struture of the xylem tissues, nutrients nd seondry metolites were lso involved, nd require further investigtion. Aknowledgements This reserh ws supported y the Fundmentl Reserh Funds for the Centrl Universities in Chin (TD211-6). Referenes [1] Anulewiz AC, MCullough DG, Cppert DL (27) Emerld sh orer (Agrilus plnipennis) density nd nopy diek in three North Amerin sh speies. Aroriulture Urn Forest. 33(5): [2] Bosu PP, Wgner MR (28) Antomil nd nutritionl ftors ssoited with suseptiility of elms (Ulmus spp.) to the elm lef eetle (Coleopter: Chrysomelide). J. Eon. Entomol. 11(3): [3] Blleni P, Gottrd K, Kyum A et l. (23) Lol dpttion nd eologil genetis of host-plnt speiliztion in lef eetle. Oikos. 11(1): [4] Co B, Xu X (24) Inset resistne of trees nd its hemil mehnism. J. Ningxi Agri. College 25(4): [5] Etges W, Ahrens M (21) Premting isoltion is determined y lrvl-rering sustrtes in tophili Drosophil mojvensis.v. Deep geogrphi vrition in epiutiulr hydrorons mong isolted popultions. Am. Nt. 158: [6] Ge F, Wu KM, Chen XX (211) Mjor dvne on the intertion mehnism mong plnts, pest insets nd nturl enemies in Chin. Chinese Bull. Entomol. 48(1): 1-6. [7] Hou TQ (1986) Emerld Ash Borer. Institute of Zoology, Chinese Ademy of Sienes, Agriulturl Insets of Chin (Vol.1). Beijing: Chin Agr. Press 445. [8] Hung JS, Ding M, Go ML (1993) An investigtion on the inset resistnt sequene of 51surin provennes to Anoplophor hinesis (Forester). J. Fujin Forest. Si. Tehnol. 2(3): [9] Herms D, Reek E, Smitley D et l. (1993) Interspeifi vrition in sh resistne to emerld sh orer. Emerld sh orer reserh nd tehnology development meeting, Mihign 24: 33. [1] Hk RA, Jendek E, Liu HP et l. (22) The emerld sh orer: new exoti pest in North Ameri. Newsletter of the Mihign Entomologil Soiety 47(3&4): 1-5. [11] Jednek E (1994) Studies in the est plerti speies of the genus Agrilus Dhl, 1823 (Coleopter: Buprestide). Entomol. Prol. 25(1): [12] Kessler A, Hlitshke R, Bldwin IT (24) Silening the jsmonte sde: Indued plnt defenses nd inset popultions. Siene 35: [13] Kthleen SK, John PB, Roert PL (213) Ftors ffeting the survivl of sh (Frxinus spp.) trees infested y emerld sh orer (Agrilus plnipennis). Biol. Invsions 15: [14] Liu JL, Wen JB, M FY et l. (1999) Timer Antomil Struture of 9 Tree Speies nd Their Resistne to Longiorn Beetles. J. Beijing Forest. Univ. 21(4): [15] Li HP, Hung DZ, Wng ZG et l. (24) Reltionships etween Morphologil Chrteristis nd Tissue Struture of Poplrs nd Dmge y Anophor glripennis Motsh. J Northest Forest. Univ. 32 (6): [16] Li JD, Sng YQ, Bi HT et l. (27) Study on the reltionship etween rk inlusion of 4 with the resistne to Aprion germri (Hope). Henn Sienes 25(4): [17] Mrshll JM, Storer AJ, Frser I Mstro VC (21) Effiy of trp nd lure types for detetion of Agrilus plnipennis (Col., Buprestide) t low density. J. Appl. Entomol. 134: [18] Qin JD (1995) Studies on inset-plnt reltionships: reent trends nd prospet [J]. At Zool. Sini 41(1): [19] Rghu S, Drew R, Clrke AR (24) Influene of host plnt struture nd mirolimte on the undne nd ehvior of tephritid fly. J. Inset Behv. 17(2): [2] Seung CH, Willimson RC, Dvid WH (25) Lef iomehnil properties s mehnisms of resistne to lk utworm (Agrotis ipsilon) mong Po speies. Entomol. Exp. Appl. 145: [21] Wei X, Dik R, Wu Y, Sun JH (24) Emerld sh orer, Agrilus plnipennis Firmire (Coleopter: Buprestide) in Chin: review nd distriution survey. At Entomol. Sini 47(5): [22] Wng ZZ (21) Study on resistne of different (vriety) to Holoerus hippopheolus (Lepidopter: Cosside). Beijing Forestry University Mster s thesis. [23] Yu CM (1992) Emerld Ash Borer. Xio GR. Forest Insets of Chin (2 nd edition). Beijing: Chin Forestry Press [24] Yng XY, Yn XH, Zhou XB (1992) Effet of Nutrients in Poplrs on Resistne to Anoplophor noilis Gngluer. J. Northwest Forest. College 7(3): [25] Zho TH, Chi CG, Go RT et l. (25) Supplementry study on life history of emerld sh orer, Agrilus plnipennis, in different res of Chin. Forest Pest nd Disese 24 (6): [26] Zho TH, Go RT, Liu HP et l. (25) Host rnge of emerld sh orer, Agrilius plnipennis Firmire, its dmge nd the ountermesures. At Entomol. Sini 48(4):