BIOLOGICAL CONTROL OF SOME PESTS INFESTING OLIVE TREES IN EGYPT

Abstract

The oli\C psylla. F:uph\•1/uru strwninea Log. (Homoptcra­ Aphalaridac) and the ulivL !t.:af moth. Palpita uniunalis (Hb.) (Lepidoptera - Pyralidm;) an: important pcsts ol' olive tre<.:s. causing nuch damage in orchards. 1-:colug.i( tl sltldi ..•.-. un F s,•.r•,,ull.ilc(/ <Hid ih pald"•lt,;d

Psvllaepilagu,• ,-up/n-1/urue wet•.: carried out during two succcsst\e seasons ('.;member 1992-.lunc 1994) in an orchard containi1 g unsprayed oliVt.: tre.:s at lsmailia governorate. l:luctuaticln or E. S{/'(//lli/1 (/ population on olive trees showed two peaks. The lirst pL•ak occurred during thc tirst two weeks of January. while the sewnd was during the first two weeks of April in the two successive seasons. Studying the population of E strami•u'u at di lfcrctll olin• tree kvcls showed that the greatest numbers or immature stages <lCcurred at the medium kvel. h1llowcG by the lower kv.:l and then the upper level. Three hymenopterous parasitoids were recorded !rom sampks of L. stnuuilil'Li cullcdcd ,lurint'- the stud) pc:riud. i . .:. one: prtill<ll') p< r<J:-iiPid.i.c:. Psrllu phugus euphrl/urae Silv.

(llymenoptcra- r-:ncy rtidac: ). parasiti;ing tlw 51

instar nymphs of

E .1traminea,and two sccondar) parasitoids.i.c. Pachyneuron iiJUscun"n l .. ( llyJn<.:tlllpl<:ru- Pt<:romalid<Jc:J and Aluriella f'ICI<I Andre. (llymcnoptera- J\phelinidae). Percentage of parasitism by P.e> tJ!nlluru<: under lield wnditiuns had been estimatt:d. The data indic:ated that in the !irs! season of investigation. the total percentage of paras<tism reac:hc:d its peak of (83.2 %) during •he lirst half or May, Vhik in the: second season. it n.:ached its maximum (79.7 %) in the st:cund half of Apri!. l'c:t-cent<,gc 1>1' ll\ j)L'rpar:tsitism <mckr field conditions had been studied .ilso.