Indian Journal of Experi mental Biology Vol. 41 , ove mber 2003 . pp. 1346- 1348 Occurrence and cross infectivity of granulovirus of field bean pod borer Adisura atkinsoni Moore K ara yan an* Projec t Direc torate of Biological Control. Hebbal. Banga lore. 560024 . India Rece i l'ed 7 February 2003: rel'ised 27 May 2003 A granulovirus (G V) was isolated fro m th e fi eld- bean poel borcr. Adisllm {/tkil1.wJll i. Electron microscopi c obse rva ti on showed capsult: or granu lar shaped occlu sion bodies. The virus was hi ghl y virulcnt aga inst seco nd instar larvae II hcn les ted al I x 10" occ lusions/larva throu gh food , urface (pod/secd) contaminati on lec hniquc. The incubati on peri()(1 ranged from 6- 10 days in Ihc casc of sec ond in stal' larvac. In contrast 10 gree n co lou red healthy larvae. GV in fecled A. mkillsolli became bro wni sh/ pal e Ilhite in co lour mos tl y due to accumul ation of large number of occ lu sion bodi es . Study on the crllSS infectiv­ ity of A. mkillsolli GV to gram ca terpillar. Helic(}\ 'I' I"/ }(1 arllligera reveal ed the hi gh susce pti bility of !-I. arllligera to A. mkill­ sOlli G V. Ihereby widening thc sc ope of cont ro lling both lhe specics on lhe sam e cropping sys tem . This is the fi rst record of GV fnlm A. mkillsolli from India. Keywords : Adi.wrt/ atkillsolli. Granulovirus. Gross-infec ti vity Fi eld bean LaNab pll rpurells (Linn .) Sweet is an im­ supernatant was then decanted and further centrifuged portant pul se - cum vegetab le crop. A lthou gh about at 12,000 rpm for 30 min. The differen tial cen tri fuga­ 5S in sect spec ies and mites have been recorded on tion process was repeated twice and the resultant pel­ field beans, onl y a few of th em are considered to be let was re suspended in sterile distilled wa ter. The important and known to appea r re gul arl y cau sing eco­ number of capsules/ml of th e stock suspension was nomi c loss while oth ers arc casual fee d e r~. Of th e 8 determined us ing a Petrauff- Hausser counting cham­ spec ies of pod borers reported to cause damage to the ber. A test wa s conducted to determine its pat hogeni c­ crop, Adi.l'lIm alkillsolli Moore: pl ume moth, ity against second instal' larvae of A.alkinsoni. Second Sl'hoello relies all isor/au\' /II.1' Wa I ker and J-I e/i col'e ' pa in stal' larvae (30) were inoculated with a dose of anlligero Hubner are th e more import ant on es, cau s­ I x lor' occ lusionliarva by food surface contamination ing hea vy damage hy wa y of feed ing th e devc loping tec hnique. T he larvae were reared individually on th e pods and reducing the marke tabl e yield I. A granulovi­ virus-contaminated diet till th eir death. Similar nu m­ rus (GV) was i.-;o lated from a few dead cate rpillars of ber of same instal' larvae, treated without virus serve d i\. Olkil1sulli collected from the fi eld in and around as co ntrol. The dead larvae were diag nosed by micro­ Ba nga lore. The present communica ti on de al s with sco pic ex aminati on of th e squ as hed preparations for ()bse r va ti o n~ made on th e sy mpt omotology and gross th e prese nce of ca psules. In ord er to tes t its cross in­ pat hology or A. Ctlkill.l'oni larvae, when th ey were ad ­ fec tivity, a preli minary study was conducted with GV mi ni stered with known quantity of G V thro ugh food of A. alkinsol1i against 8 lepidopteran pests l Table I ) su rface (pod and seed) contamination technique along at a concentration of I x 106 occ lusions/ml either with ce rt ain preliminary cross infec ti vit y stu dies. through diet su rface or lea f surface co nt aminat ion Granular occlusio:l bodies of GV we re pu ri fi ed technique depending on th e av ailabi lity of artificial from th e diseased larvae of !\, olkinsoni by differential diet for the respec tive insec ts . ce ntrifuga ti on fo llowing the meth od of Narayan an"­ The pathogenicity of A. alkinsoni GV re vealed Diseased larvae were homogeni zed with distilled wa­ 100% mortal ity of th e second instal' larvae when ad ­ ter for 3 min and th e hOll1ogenate was th en filtered ministered through diet surface contamination tech­ twice through severa l layers of muslin cloth and th e nique. The incubation peri od ran ged from 6-10 days. filt ra te was ce ntri fu ged at 1000 rpm for 10 min. The The sy mptoms of the GV infected A. alkinsoni were * Correspondent author: E-mail : KnJJdbc(l) rcd i lTmai l.colll genera lly comparable with th ose of most of th e granu ­ Fax: (080) 34 11 96 1 losis viruses reported in other insects. Li vi ng diseased NOTES 1347 Tablc 1- Cross infccti \'ity of A. iilkillSolli c.;V to othc-r lepidopt cran pcs ts amc or thc inscct No. or in.'e.:ts lI scd M ortality (%) Pupation ("Ir ) Chilo par/el/II.I (S\\ illhoc) 30 I O() TrichoJlllIsio IIi (1Iuhncr) 10 100 Opisill(/ (/rl'lI (1s( 'I/(I (Walkcr) 20 I O() Cailm ('wlll'l/a (Wall,cr) 10 100 Core."m ('(pfw!rJll iclI (Stainton) 30 100 CuI/crill 1II1'1/01lCI/(I (Linllacus) 3D 100 SJlodul',erfl filllm (Fahricius) J() IUO ffl'lic()\'erf)a arllligel"O (H uhncr) 10 100 larvae of A.Olkillsoni showed typical sluggishn ess in their moveillellt and we re :l lso less respnllsive to ex­ tcrn~ 1I tactile stimuli . Further. in contr:lst to green col­ ou red healthy larvae,the GV infected!\. al/':illsoni be­ came light whit e in co lour (Fig. I ), ancl it was well pronoun ced on the ve ntral side 1ll0sLl y due to the ac­ cumul at ion uf large number of occlusion bodies. Unlike tha t of NPV of A. a//':illsolli. th e sk in of GV in fec ted A.OIkins()ni H'as Ilot liquefied. A fter death, a characterist ic w hi te liqui d oozed out through the ski ll aft er piercing. This flu id was of the consistency or t thin cream, and contai ned large numbers or capsu les . Upon diss 'ction or a diseased larva. ex treme ly en larged and thickened fat body was noticed w hich appeared <.jui te whitc whe n compared tll the less mas­ : i ve and practically co lourless adipose tissue of the hea lthy larva . Afrer death, the illleguIllent remained rather tough and leat hery in CO lltr:lst to larvae inl"ccted with nuclear po lyhedrosi: vi rus. in which case th e integ uillent ruptured qu it e ea: ily . Exaillination (1f the tissue in wa ter mounts w ith either th e pilase-contrast or da rk rieid miclw;copc. revca led Il Ulllerous capsules emanating from thc ruptured cell~. Samples oj" occlu­ Fig. 1- Gr<llltilovirus ((;V) infected I\. (llhillll'lIi la r\ al' Ix 31 . sion hod ie s of GV fWIl1 ~()ll1e or the insec t:.. for \\ hich I:ig . .\ - 1-1 . llnlligl'm la rvae cross infected hy /1. IIf/"il/ l()lIi G\'. pos itive diagnosis had been ll1ade w ith phase-con trast Note the whitening or the hotly colou r bo th on dor,;d <Inti I <: nl r;1I side' or the botly. l ic;dthy (I-I ): and d i~c a ' etl (D ) I x ~ I microscope was further checked with electron micro­ sco pe (Fig. 2). sccond in sta l' larvae of A. (ff/':insoll; were inoculated It is CV ldellt from Tahk I that except f-I. onlligem. w ith the progeny yirus obtained from H onlligao Ilolle or th e insec ts tested was susceptible to A. w/':ill­ through food s uh <; tT~tte (pod/. eed) surfaCl: contamina­ soni GV. Funller, th e st udies on th e cross infecti vity tion techni<.jue. w hich res ulted in cent per cent mortal­ of !\.(If/.:illsulli to H orllligem revea led th e high ity. Thus the virus reta incd th e pat hogen icily I'm susceptibility of H onlligem to hetero logous GV of II. ol /.:illSOlli evcn after passage through H (I rill igel"O . A . ot/':insf)lI i. rec ording cc nt per ce',ll mortality of th ereby co nrirll1ing th e cross inrecti vity or A. OI/':ill ­ second instal' laryae w hen admi niste rcc\ at I x I d' sOlli C\I against II. o m ligera. occ lusion/ larva through food surface contamination Generally. insect vi ru ses are considered to be rela­ tech nique. In contrast to hea lthy H orlllige ro larvae, ti ve ly spec ies-spec ific or at leas t havc a limited h\.) st the GV ini"ccted H wmigera be 'al11 e pu ffy and pale range.l . However. cro:..s infec tion of insect v ir u ~es be­ \vhite in co lour (Fig.