Abdul Bakir, Mohammad

Abdul Kadir, Hussan

Abdul Samad, Norani

Hussein, Mohd Yusof

Sajap, Ahmad Said

Universiti Putra Malaysia Institutional Repository

FOR CategoryF10900:'Agricultural SciencesEFFECT OF ULTRA VIOLET LIGHT ON EFFICACYOF SPODOPTERA LITURA (F.) (LEPIDOPTERA:NOCTUIDAE) NUCLEAR POLYHEDROSISAS'S' 1 . 1 ' 2 ' ·3.. ajap, M.A ..Bakir. N.A. Samad. M.Y. Husseinand H.A KadilDepartments of lparest Management, 2Biochemistry and Microbi.ology, and 3Plant ProtectionUniversiti Putra Malaysia, 43400 UPM, Serdang, Seiangor,Malaysia '4MARDI Serdang, G.P.O Box 12301, 50774, Kuala Lumpur,MalaysiaKeywords: nuclear polyhedrosis'virus (NPV), ultraviolet, Spodoptera litura.IntroductionFor the development of viral insecticides ultraviolet (UV)spectrum of sunlight is the main obstacle' and limiting theconsistent success of entomopathogens as microbial controlagent. All representative types of microbial insecticides (i.e.bacteria, fungi, protozoans, viruses) are inactivated by expo-sure to the ultraviolet-A (UV-A), ultraviolet-B (UV-B) spec-trum (280- 400 nm) of sunlight (Ignoffo et al. 1977). Inmany cases, field applied pathogens lost at least 50% of theiroriginal activity within severaldays, Factors among tem-perature, pH, Chloride ions, water quality and sunlight- solarradiation was found as the most significant factor to inacti-vate the polyphagous Spodoptera litura controlling nuclearpolyhedrosis virus, (SlNPV) in a brief period of exposure(Tuan et al. 1995,). In this study effects of three ranges ofUV light UV-A (365 nm), UV-B (300 nm), UV-C (254 nm)were studied which will provide information to develop UV,_protectant and formulation of viral pesticide,Materials and MethodsUltraviolet radiation study: In this study, 20 ml of polyhedralinclusion bodies (Plfls) suspensions (1x 108 pms / ml) werepipetted onto the bottom of glass petri dishes (90 mm) andexposed to UV-A (365 nm, 8 Watt, UVA-18, Ultra- LumInc., California), UV-B (300 nm, 8 Watt,UVB-18, Ultra-Lum Inc., California) and UV-C (254 nm, 8Watt, UVC-18,Ultra-Lum Inc., California) with open lids at a distance of 10cm from the UV light sources. Virus suspensions were ex-posed to UV for lh, 5h, 20 h, 168h (7d) and 360 h (15d).After the exposure period the volumes were adjusted to 20ml and pms were suspended and dispensed into glass bottlesand stored at _200 C until bioassay. Third instar larvae werebioassayed (5 x 106 PIBs I larva) with standardised leaf discmethod (1m et al. 1988) until the larval death or pupation.Treatments were replicated four times using thirty larvae perreplicate per treatment. Larval mortalities were transposed toobtain the mean and standard error of the mean and subjectedto an analysis of variance (ANOV A) appropriate for a ran-domised block design. Treatment means were separated byDuncan's multiple: range' procedure' (DMRP) (cc: -= ~0.05).(SAS Institute Inc. release 6.12).Results and DiscussionUV-A did not affect adversely on Spodoptera litura NuclearPolyhedrosis Virus (SINPV) upto the exposure of 20 hours(% original activity remaining (OAR) was 100%). No sig-nificant difference was found after the exposure of SlNPVfor 20 hours to UV-A and UV-C and 5 hours exposure toUV-B with the unexposed. Significant effect of UV wasfound after 168 hours (7d) of exposure to UV-A and UV-Cand 20 hours exposure to UV-B with the unexposed. Viralinfectivity was completely destroyed (OAR was 0%) after360 hours exposure (15 d), both for the UV-B andUV-Cwith no significant difference with, the untreated control. onthe contrary, OAR was 22% in case of UV-A exposed for thesame time. But the effect of UV-B occurred significantlyearlier (20 hours of exposure) with unexposed virus. Fromthis study it can be assumed that.Uv-B (280-315 nm) iscausing more deleterious effect on virus than UV-A (315+nm), because sunlight UV spectrum actually reaching, theearth surface is UV -A and UV -B (290- 400 nm) (Ignoffo andGarcia, 1992). Similar observation was found by Jones et al.(1993). Ignoffo and Garcia (1992) found no significant effectof pH (3, 6, 9) and temperature (10, 22, 35, 50 "C) but pres-ence of free water can significantly extent the pm inactiva-tion by sunlight. Sunlight may have a direct effect on viralDNA by inducing deleterious cross Iinkinzs, strand breaks ordevelopment of labile sites or both. 'Conclusions'UV-A, UV-B and UV-C were effective in reducing the viralactivity but UV-B was the most deleterious. Sunlight.UVspectrum actually reaching the earth surface is UV-A andUV-B (290-400 nm) not UV-C. From this study it can besuggested that more emphasis should be given to protect UV-B than UV-A of sunlight spectrum to develop UVprotectantor to formulate viral pesticides.ReferencesIgnoffo, C.M;. Holstelte, P.P .• Sikorowski Sutter. G. and Brooks,W;M. (1977). Inactivation of representative species of entomopa-thogenic viruses bacterium, fungus and protozoan by an, ultra-violet light source. Environmental Entomology, 6: 411-415: 'Ignoffo, C.M. and Garcia. C. (1992). Combinations of environmentalfactors and simulated sunlight affecting activity of inclusionbodies of the Heliothis Nucleopolyhedrosis virus. Environmental'Entomology. 21(1): 210-213. 'Im, D.J .• Shepard, B.M. and Aguda, R. M: (1988). Pathogenicity andhistopathology of a nuclear polyhedrosis viurs of Spodoptera Ii·tura (F). Insect Science and its Application, 9(4): 539-542. 'Jones K.A., Moawad, G .• Mc Kinley, D.J., Grzywacz, D. (1993),The effect of natural sunlight on' Spodoptera littoralis' nuclearpolyhedrosis virus. Biocontrol Science, and Technology, 3(2):189- 197.Tuan, S.l., Kao, S.S., Leu, U.L. (1995). Factors effecting pathogene-city and stability of Spodoptera Iitura nuclear polyhedrosis virusisolate in Taiwan. Chinese Journal of Entomology. 15 (1): 47-58.Supported by IRPA GrantOl-02-04-018743

Effect of ultra violet light on efficacy of Spodoptera litura (F.) (Lepidoptera noctuidae) nuclear polyhedrosis

http://psasir.upm.edu.my/41816/1/Effect%20of%20ultra%20violet%20light%20on%20efficacy%20of%20spodoptera%20litura%20%28f.%29%20%28lepidoptera%20noctuidae%29%20nuclear%20polyhedrosis.pdf

Effect of ultra violet light on efficacy of Spodoptera litura (F.) (Lepidoptera noctuidae) nuclear polyhedrosis

Abstract

Similar works

Full text

Available Versions

Universiti Putra Malaysia Institutional Repository