Monitoring population density and fluctuations of Xyleborus dispar and Xyleborinus saxesenii (Coleoptera: Scolytıdae) with red winged sticky traps in hazelnut orchards

Bark and ambrosia beetles (Coleoptera: Curculionidae:Scolytinae) include many important pest species of forest and fruit trees. They usually prefer the physiologically stressed trees for colonization but also it is known that they attack healthy trees. Bark and ambrosia beetles are consisted of two main ecological groups, bark beetles grow in bark and ambrosia beetles in sapwood. Especially ambrosia beetles are very detrimental in Turkish hazelnut orchards. This study was carried out between 2005 and 2007 to monitor populations of Xyleborus dispar and Xyleborinus saxesenii (Col.: Scolytidae), causing considerable damages in hazelnut (Corylus avellana L.) orchards in Ordu and Samsun Provinces. The populations of the bark beetles were monitored using sticky traps with red wings that are registered and used to capture these pests. Ethyl alcohol (96%) was used as the attractant in the traps. The results of the three-year study indicated that both pest species emerged in different times in Ordu and Samsun. X. dispar emerged in large numbers in springs (March May) as overwintered adults; however, X. saxesenii emerged in large numbers in summers (June August). Population density is usually the X. dispar was found to be more. X. dispar on 05.15.2007 (398 adult/trap), X. saxesenii on.09.01.2005 (383 adult/trap) the highest catch was recorded in Samsun province.


INTRODUCTION
Hazelnut is one of the most important agricultural products of Turkey; it is cultivated over approximately 550 thousand hectares (84% of global production area), producing 500 thousand tonnes (69% of global production), of which approximately 300 thousand tones are exported (Yavuz, 2007).
Approximately 150 insect species have been detected in hazelnut orchards.However, only 10 to 15 of these species result in economic losses, varying between years and the region of hazelnut (Işık et al., 1987).According to various studies conduced in Turkey, Hazelnut weevil (Balaninus nucum L.) is the most significant hazelnut pest (Işık et al., 1987;Ecevit et al., 1995;Tuncer and Ecevit 1996 a, b;Saruhan and Tuncer, 2001;Tuncer et al., 2002).Bark beetles (Scolytidae) comprise another pest group of hazelnut (Ak et al., 2005a, b, c).These pests are a risk for stone or pome fruits, kiwi and forests, and have recently been shown to harm hazelnut orchards.Serious damage of these species were observed on hazelnut plants in low and middle altitude of region in last years (Mani et al., 1990;Raulder, 2003;Kaya, 2004;Ak et al., 2006bAk et al., , 2010)).While other pests directly or indirectly affect the quality and yield in hazelnut orchards, bark beetles (Scolytidae) cause product losses by draining young or old hazelnut branches.Additionally, as these pests spend most of their lives in the woody tissue of their host, they are extremely difficult to eradicate.Therefore, chemical control must be supported by cultural and biological control.
Controlling bark beetles depends on the emergence time of the adult females.Therefore, Red Winged Sticky Traps (ethyl alcohol baited) are used to detect their emergence and achieve mass capture.
Population monitoring of pest species is of great importance in determining the emergence time of adult individuals in order to control them.Population monitoring enabled the determination of emergence times and population fluctuations of pest species in hazelnut orchards.
Due to the high population of pests in hazelnut orchards and the importance of determining the emergence time of adults in controlling them, this study examined population fluctuation of X. dispar and X. saxesenii.Both species are important in terms of both presence and density in hazelnut orchards in Turkey.They were monitored at different locations in two provinces (Samsun and Ordu) for three years and the emergence time of adults was determined.

MATERIALS AND METHODS
The main materials of the study consist of hazelnut orchards, Scolytidae (bark beetles) species (X.dispar and X. saxesenii), Red Winged Sticky Traps and 96% ethyl alcohol as the attractant.
The trap used in the study consists of four red-colored sticky plates as a wing and a 1-liter plastic bottle hung just below them.Each wing of the sticky trap has an area of 148.9 cm 2 (14.6 cm height and 10.2 cm width).The total area of the sticky part of the trap is 0.12 m 2 .The plastic bottle has four holes to enable the alcohol to evaporate.
Population monitoring of X. dispar and X. saxesenii used redwinged sticky traps licensed for use against bark beetles, which were located in hazelnut orchards of Samsun (Terme) and Ordu (Central) provinces between 2005 and 2007.Three traps were hang at each location used in the study.Traps were placed 1.5 m above the ground and spaced 20 m from each other.Population fluctuations of X. dispar and X. saxesenii were monitored in Samsun province (41° 12 ' 37" N -36° 59 ' 32 " W) and Ordu province (40° 58 ' 48 " N -37° 55 ' 44 " W) in 2005 to 2007 (Figures 1 to 4).The numbers of trapped X. dispar and X. saxesenii were monitored weekly between March and October; traps were cleaned after each count and this process continued throughout the year.In the first year, traps were hang in Samsun location on 03.

Population density and fluctuation of X. dispar in Samsun Province (2005-2007)
The first X.dispar individuals were trapped during the last week of March (03.25.2005)   (  The pattern for X. dispar trapped in Ordu showed similarity to that of Samsun.4).

DISCUSSION
In both locations in all three study years, the emergence of adult X. dispar was determined to be between March and June, depending on temperature.The emergences during these periods were found to be non-continuous and occurred as a result of nestling of adult in different periods.Adult X. saxesenii were determined to emerge densely in the summer period between the end of June and August at both locations.Additionally, adult individuals nestling in the spring period were found in traps.
According to population monitoring over the three years in Samsun and Ordu provinces, adult individuals of both pests species emerged at different periods.The population progress of X. dispar and X. saxesenii were similar to each other at both locations.
As a result of population monitoring in Samsun and Ordu provinces, the dense emergence of adult X. dispar was found to occur in spring and adult X. saxesenii emerged in summer.Apart from these dense emergences, each species was found to make instantaneous (non-continuous) emergences.These findings support those reported by Ak (2004) and Ak et al. (2005aAk et al. ( , b, c, 2006a)).
It was found that X. dispar had higher population densities than X. saxesenii in both locations during 2006 and 2007 but not 2005.
Population monitoring of X. dispar showed that adult emergence increased during the spring season when the temperature was approximately 18 to 20°C.Similarly, a study by Kaya (2004) of mixed fruit trees (apple, pear, plum, peach etc.) found that, from 1997 to 1999, the first emergence of adult X. dispar was on May 8 th , April 26 th , and May 6 th , respectively.Schultz et al. (2002), using ethyl alcohol baited Lindgren and Japanese traps, reported that the first emergence of adult Xyleborus crassiusculus was at the end of March and the beginning of April.Mani et al. (1990), using ethanol traps, stated that X. dispar was caught in spring when the temperature was 20°C and that catches lasted for 3 to 4 weeks.In a study using ethyl alcohol funnel traps in fruit orchards in Canada (Creston), White (1992) reported that X. dispar emerged at the end of March and beginning of April and had two peaks in April and June.Ciglar and Boric (1998) stated that 98% ethyl alcohol diluted 1:1 with water could be used as baiter in winged traps; X. dispar emerged in spring when the temperature was 20°C and the emergence lasted from the last week of April to mid June.The results of population monitoring of X. saxesenii showed the emergence of adults in the spring season when the temperate reached 18 to 20°C, as in X. dispar, and the dense emergence was detected in June-August.Similarly, a study by Markalas and Kalapanida (1997) examined flight models of some Scolytidae using an ethyl alcohol baited slot tarp in an oak forest in Greece between 1992 to 1993; it was reported that X. dispar emerged in high numbers between March and June, and X. saxesenii from the end of April to the end of August.In a study of flight dynamics using alcohol traps, Raulder (2003) found that X. saxesenii and X. dispar began to fly in spring (end of March or the first week of April) when the daily temperature was 18°C and above, lasting until autumn; and that the period of dense flight occurred at the end of April to mid June.A survey of Scolytidae in Oregon forest (Cramer, 2005) observed the first emergence of X. saxesenii in mid February when the temperature reached 18°C and lasted until the end of autumn, with the period of highest emergence being from the beginning to the end of June.
X. dispar was found to have higher population density than X. saxesenii and the emergence of its nestled adults was observed in spring (March -April -May).This result highlights the importance of determining the appropriate period to commence the control of especially X. dispar.In this period, the control (mechanical, biotechnical and chemical) of nestled adults can give effective results.During the summer period, X. dispar showed low emergence from the end of June to mid August.X. saxesenii was found to emerge in low density in spring, depending on temperature, with dense emergence observed in the summer season (June -August).Therefore, control of this species should be conducted during this period.
15.2005, and removed on 10.25.2005.In Ordu location, they were hang on 03.31.2005 and removed on 10.20.2005.In the second year, they were hang in Samsun location on 03.15.2006 and gathered on 10.26.2006, and in Ordu location they were hang on 03.16.2006 and gathered on 10.27.2006.In the last year of the study, the traps were hang in Samsun location on 03.21.2007 and gathered on 11.01.2007.In Ordu location, they were hung on 03.23.2007 and gathered on 10.15.2007.
The first catch at Ordu occurred in the first week of April (04.08.2005) and high catches were observed in March and April.The highest catch was recorded on 05.20.2005(146 adult/trap).
2007 (Figure2).The data indicate that the emergence of X. dispar depends on seasonal factors and that traps should begin to be used one week later than those at the Samsun site, and that chemical control should be started by the first week of April, as in Samsun province site.Both provinces showed a population decline at the beginning of May and an increase at the beginning of June.Therefore, commencing chemical pest control by the first week of June is of great importance in controlling populations.Population density and fluctuation of X. saxesenii in Samsun Province (2005-2007)As with X. dispar, individuals of X. saxesenii were first recorded in traps in the last week of March and lasted until the last week of September in Samsun.The highest catches of X. saxesenii in Samsun generally occurred in July and August in each of the three study years.Population density and fluctuation of X. saxesenii in Ordu Province (2005-2007)In 2005, catches of X. saxesenii in Ordu were recorded