Özet:

Population fluctuations, biology, damage and host plants of Otiorhynchus spp. were investigated in a 0,3 ha strawberry field, which consists Osmanlı and Sultanhisar varieties in İzmir-Menemen (Emiralem) in 1995 and 1996. Otiorhynchus spp. produces one generation per year. Larval duration was 180 days and 189 days whereas pupal duration was 18 and 38 days in 1995 and 1996, respectively. First occurrence of adults was recorded in 08.05.1995 and 17.05.1996. Larval duration was found as 190 days, whereas pupal duration was 34 days in field cage in Bornova in 1999. The first occurrence of adults was recorded in 11.05.1999 and emergence period of adults was 7 days in this cage. Besides strawberry, olive and walnut are alternative hosts in Menemen. Larvae of Otiorhynchus spp. caused the most important damage by feeding on fine roots of plants and girdling a hole in the main root. Development stops in damaged plants. Leaves and fruits of such plants were smaller than those of healthy ones. Fruits of infested plants ripen earlier than the healthy ones. They seemed wilted or became flaccid. Infested plants became wilt, dried and died. Oviposition periods of O. lubriculus and O. balcanicus were 31±7.43 and 22.25±3.56 days, whereas daily and total fecundities were determined as 22.76±3.68 and 36,57±8.49, 128.5±34.28 and 128±19.37 eggs, respectively. Incubation periods of the two species were calculated as 8.47±3.56 and 10.07±0.66 days. Hatching rates of O. lubriculus and O. balcanicus eggs were determined as 85.32±7.68 and 38.33±10.33% under the conditions of 25±1 ºC temperature and 50-60 % relative humidity. The first egg laying was on 30.09.1996 and hatching occurred on 06.10.1996. Incubation period lasted 13.57±0.9 days, whereas larval and pupal duration were 139.7±1 and 18.7±1 days, respectively. The first occurrence of adults was recorded on 04.04.1997. Life span of adults of O. lubriculus were determinedas 231±9.9 days under conditions of 20±1 ºC temperature and 50-60 % relative humidity. According to the results obtained from the bio-ecological studies, it has been concluded that the most suitable time of application should be in October and/or November when larvae of Otiorhynchus spp. have just begun feeding and damaging on thin roots actively.

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