Population Studies of SaIne Major Insect-Pests of Apple and their Natural Eneinies in Azad I( ashmir (AJK)

Abstract

The present studies on some major insect-pest of apple and their natural enemies were conducted in three localities and six sitews of districts, Bagh, Muzaffarabad and Rawalakot in Azad Kashmir, Pakistan, during 1999-2003. These studies were mainly focused on two key insect pest of apple i.e., San Jose scale (SJS), Quadraspidiotus perniciosus (Comstock),Codling moth,Cydia pomonella (L) as thes pests are known serious threats for the apple growers. An attempt was also made to study some of the natural enemies of these dangerous pests. The current studies are the first ever systematic scientific work on apple crop in Azad Kashmir, Pakistan. From the present study, it is quite obvious that key pest of apple like SJS badlly infest both indigenous and introduced cultivars. It was found that out of three studied localities ,and six sites, Sarfraz Abbasi Apple Orchard (site-A) at dheerkot locality was found more infested with SJS, and at the same time, it was also identified that Star Crimson variety of apple was more susceptible for SJS attack compared to variety like Banky. Investigation on larval infestatioin of C.pomonella was carried out during the field study. It is very clear from the current findings that out of 633 apples (fruits) of different sites of Dheerkot locality, Mohammad Tazzem Khan Apple Orchard (site-B) was found heavily infested with Codling moth larva. Interestingly, it appeared that both indigineous and introduced varieties were infested with larva of Codling moth. Kashmiri variety was more susceptible (90.26 %) at site-B, compared to StarCrimson (8 .33%) at site-A. The overall average larval infestation was 45.49 %. It appeared from the results thar larval incidence starded in the second week of June and lasted till the harvest of the fruit in mid August at Dheerkot during 1999. The monitoring of adult Codling moth was also studied at two site of Dheerkot locality during 2003.Result of this study showed a significant difference (P<O.OOl) of adult Codling moth distribution during different months. During the study two peak populations were recorded, i.e., one in the month of April and second in the month of July, which suggest two generation of the Codling moth in Dheerkot locality. The distribution pattern of Chi/ocorus infernalis (Mulsant), a predator of SJS, on apple tree was determined. Throughout the samling period, a total of 498 specimens (larvae, pupae and adults) were collected from two localities (Rawalakot and Dheerkot). Greater numbers (471) of specimens were collected from Dheerkot locality compated to few numbers (71) from Rawalakot. Out of 427 specimens, 378 were recorded from site-A, which shows a clear indication of predator -prey interaction, because more population of prey (SJS) were also recorded from site-A at Dheerkot locality. The population of predator on apple tree varied significantly (P<0.005) throughout the sampling period at Dheerkot.The high population was recorded during mid April through first week of May 2000. The predation potential of C.infernalis on SJS was examined under the field insectary condition at Rawalakot. The feature of finding showed that overall both the sexes (male and female) consumed significanftly (P<0.001) different number of scales, Q.perniciosus.Adult female beetle consumed more scales than male. Although both the sexes ate significantly (P<O.OO 1) different number of SJS at different prey density, none of these consumed all the offered prey.