J.Biol.Control, 4 (2), 77-79, 1990

Biological Effects of Parasitism by melanoleuca (Fletcher) on perpusilla (Walker) - R.S.BAL, Z.S.DHALIWAL and S.S.BAINS Department of Entomology Punjab Agricultural Uuiversity. Ludhiana 141 004 ADSTRACT Biological effects oC parasitism by (Fletcher) on the nymphal and adult stages of PJrilla perpllsi/ia (Walker) have been JnvcstJgated under laboratory condItions.· Parasltold-Innlcted . Injuries caused high mortality (95.9 %) In the first Instal' nymphs within t\Vo days of parasitlsatlon. Appreclable nymphal mortality (70%) also occurred In the parasltlsed second, third, fourth nnd firth Instal's In the form of wcaknymphs, .nymphal-adult Intermediates and \Veak adults though after a prolonged nymphal duration In the later three instars. Fccundlty of the parasltlscd adults was reduced by 21 per cent but thelr longevity was enhanced slgnlflcanLly. Key Words: "Epiricania melanoleuca, Pyrilla perpusil/o, biological effects, parasitism Population of the leafhopper, by Dhaliwal aud Bains (1983). Effect of Pyrilla perpllsilla (Walker), a sporadic of parasitism by E. melanoleuca on the survival sugarcane, is suppressed by the natural enemies and development of various nymphal instars of . during the inter-outbreak period (Brar~ 1978). pyrilla was dctcrmined under laboratory condi­ Epiricania () melanolellca tions from August through October, 1986. (Fletcher). an ectoparasitoid of nymphal and Nymphs of each of the five instars were taken adult stages of pyriJIa, acts as a key mortality from tbe cuhure and were released into rearing factor of pyrilla population during monsoon sets @ 10 individuals per set. The were period in Punjab (Brar and Bains~ 1979). Due parasitised artificially by keeping the glass to the rapid rate of illcrease and longer period vials containing lab-reared~ newly-hatched lar­ of activity of this , it has showll its vae of the parasitoid, iuto the rearing sets. The potential as an effective biocontrol agent nymphs showing signs of parasitism were through artificial a'ugmentation (Misra and separated out and reared· to record their Pawn, 1981). Though abc numerical trend ill develqpment l)criod and adult emergence. Un­ populations of the and thc parasitoid has parasitised llymphs ,from the culture were also been studicd under llaturalcolldiliollS by many reared separately as control. entomologists, the information 011 the deleterious effects produced by the CI)il>yropid To determine· the anomalies in the on the host is sti1lscanty and controversial. parasitised adults ofpyriUa, the newly emerged Keeping in view the need for proper under­ adults were parasitized by the procedure as standing of the biological rdationshil) between described ill case ofllymphs. Eighteen pairs of the host and the parasitoid. the present study each of the parasitised and healthy adults were was undertaken. . released ill rearing sets @ one pair per set to compare their longevity and fecundity. The MATERIALS AND METHODS number of eggs laid by tbe females were counted daiJy aud removed from the sets. The Laboratory culture of llyrilla was main­ data were compared by applying Ct' test. tained by rearing it on sugarcane leaves in the rearing sets followiugthc techniquc developed 78 Bal et a1.

RESULTS AND DISCUSSION· in line with those of Bindra and Brar (1978) who reported emergence of normal adults from The data related to the parasitism effeclS the parasitised penultimate instar nymphs. In produced by E. melanoleuca on nymphal ~nd case of parasitised last instar nymphs, 50 per adult stages of P. perpus ilia are presented in cent adults were pro.duced out of which only 20 Tables 1 and 2 respectively. . per . cent were normal. Though longevity of such adults (males and females) was the same Exposure of first instar nymphs for as that of the ones emerged from unparasitised parasitisation resulted in 95.9 per cent mor­ nymphs, the fecundity of these adults was com- tality within two days before the appearance of 1?~ratively low (96 eggs/female). any signs of parasitism. The remaini~g ones Data recorded on the parasitised adults in­ exhibited parasitism after 11-13 days. Such dicated that males (39.33 days) and females nymphs, however,· could not tolerate· the (46.78 days) survived for a significantly longer parasitoid feeding and died after an average period than their unparasitised counterparts nymphal life of 20 days. High mortality in early (Table 2). Similar prolongation was also ob­ nymphal instars has been reported to be due to· served in the pre-oviposition period of the injuries caused by the parasUoid (Mukerji and . parasitised females. The egg laying capacity of Venkatraman, 1948). The mean developmental the parasitised females (125.17 eggs/female) period of nymphs parasitised in the third, fourth was, however. reduced by 22.05 % as compared · and fifth instars was prolonged significantly, to that (157.11 eggs/female) of the un­ the maximum prolongation (42.6 days) being in parasitised ones. The present findings support the fourth instar. the observations of'Gupta (1940) and Brar and Bains (1979) who reported reduction in fecun­ Mortality among the first four nymphaJ In- dity in female pyrilla parasitised by. E. · stars due to parasitism indicated that all the melanoleuca. However,. the earlier reports in­ individuals died as weak nymphs, nymphal- dicating no effects of parasitism on fecundity · adult intermediates and weak adults (lived upto (Mukerjiand Venkatraman, 1948) and reduc- 7 days). The present findings, however, are not Table 1 •. Effects of pnr~slt1Sin by B. melanoleuca on various nymphnllnstars or P. perpusilla Mean longevity Number Mean Mortality (%) as Survival of normal adults of longevity of Calculated (%)as (days) Host stage nymphs nympbs 'C value Inter- normal Nymphs Weak tested (days) mediate adults Male Female adults forms I-instar (1)- 73*- 20.0= 1.00 100.00 0.00 0.00 0.00 II-instar (5) 34 32.3 = 4.82 1.205 88.23 5.88 5.88 0.00 III-instar (13) 20 37.1 = 5.41 5.868··· 70.00 25.00 5.00 0.00 IV-instar (21) 20 42.6 = 7.76 8.063··· 35.00 45.00 20.00 0.00 V -instar (28) 20 37.7 :1:14.38 2.500··· 40.00 10.00 30.00 20.00 32 30 Control 31 31.3:t: 0.89 0.00 0.00 0.00 100.00 31 34 (Unparasitised)

• Figures in parentheses indicate the age (days) of insects at the time of parasitisation •• Seventy nymphs died within two days before showing signs of parasitism ••• Significant (~ = 0.05) . 79 Effects of E. melanoleuca on P. perpus ilia

Table 2. Effects orparasltlsm by E. melanoleuca on adult stage or P. perpusilla Longevity Reduction in Pre-oviposi- (days) Fecundity fecundity due Type of adults tion period per female to parasitism (days) Male Female (%)

Parasitised 39.33 % 7.33 46.78 % 9.18 31.44 :t 3.66 125.17 % 25.60 22.05 % 15.53 (30-54) (36-70) (26-41) (81-175) (20 - 41.18)

U n-parasi tised 32.11 %. 6.88 34.22 % 10.14 16.39 :t 4.07 157.11::t: 23.70 (20-50) (23-70) (11-25) (105-190) Calculated 't' 4.06* 6.65* 9.78* 3.54* value (P=O.OS) Figures in parentheses indicate range tion in longevity of parasitised adul ts (Brat and Walker. Unpub. Ph.D. Thesis, Punjab Bains, 1979) of pyriIla are at variance with tbe Agricultural University, Ludhiana. results of tbe present study. BRAR.R.S. and BAINS,S.S. 1979. Population dynamics of Walker­ Mortality factors. Indian J. Ecol., 43,441-442. Most of tbe parasitised nymphs died before DHALIWAL,Z.S. 1982. Disruptive influence of contributing to tbe next generation through abiotic factors and insecticides on the natural adults. Though parasitoid-induced prolonga­ enemy complex of Pyrilla perpusilla (Walker) tion in the longevity of pyrilla (nymphs and (: ). Unpub.Ph.D. Thesis, Punjab Agricultural University, Ludhiana. adults) may lead to feeding by the individuals DHALIWAL,Z.s. and BAINS.S.S. 1983. A labo­ on sugarcane for additional number of days, yet ratory technique for rearing sugarcane the feeding rate of parasitised individual may leafhopper, Pyrilla perpusiUa (Walker). Uttar be below normal. Tbe reduced fecundity of Pradesh J. Zool., 3, 164-165. GUPTA,B.D.1940. On Epipyrops (sp.n.) a parasitised adults of postmonsoon period may parasite on the nymphs and adults of sugarcane . be helpful in reducing the overwintering egg leafhopper (Pyrilla spp.). Curr.Sci., 9, 132·133. population of pyrilla under natural conditions. MISRA,M.P. and PAWAR,A.D. 1981. Biological As the third instar nymphs are preferred by E. trials against sugarcane pyrilla. Pyrilla perpusiIJa (Walker) in eastern Uttar Pradesh and melanoleuca for parasitisation (Dhaliwal, elsewhere in India. In "Biological Control 0/ 1982) which are capable of tolerating the Sugarcane Pests in India". (Sithanantham. S. parasitoid feeding, timing of artificial releases and Solayappan. A.R. eds.) p. 75-78. Tamil of E. melanoleuca may be decided accordingly. Nadu State Federation of Co·operative Sugar . Factories Ltd., Madras. REFERENCES MUKERJI,S. and VENKATRAMAN,T.V. 1948• Studies on Epipyrops melanoleuca Fletcher BINDRA.O.S:and BRAR,R.S. 1978. Studies on the (: ), an ecto-parasite natural enemies of Pyrilla perpusilla Walker in of sugarcane leafhopper, Pyrilla spp. the Punjab. Indian Sug., 28,247-252. (Homoptera : Fulgoridae). Proc. Zool. Soc. BRAR,R.S.1978. Role of natural enemies in the Bengal, 1.91-102. population dynamics of Pyrilla perpusilla