Larval Parasitoids and Parasitism Rates of the Cereal Leafminer, Syringopais temperatella (Lederer, 1855) (Lepidoptera: Scythridae) in Cereal Fields of Northern Cyprus

The current study was conducted in 42 wheat, barley and oat fields of 18 villages in the districts of Lefkoşa (Nicosia), Gazimağusa (Famagusta), Girne (Kyrenia), Güzelyurt (Morphou) and İskele (Trikomo) of Turkish Republic of Northern Cyprus in the years 2012-2013. A total of 1587 and 865 leaves infested with the larvae of the cereal leafminer, S. temperatella were collected between March and April months in the years 2012 and 2013, respectively. Larvae were kept inside boxes covered with nets in the laboratory at 25±1°C, 65±5% RH, and 16L:8D photoperiod. They were controlled daily for emergence of moths and parasitoids. Following a completion of the emergence of the moths and parasitoids, parasitism rates of S. temperatella larvae was calculated as the number of parasitoids over the total count of parasitoids and moths. Specimens from the parasitoid species obtained in the survey were stored in 70% alcohol in small plastic tubes and sent to Prof. Dr. Ahmet Beyarslan (Bitlis Eren University, Faculty of Science and Literature, Department of Biology, Bitlis, Turkey) for identification.

Before two-way ANOVA, the data on parasitism rates were transformed by using Arcsin Transformation. The arcsin transformed data were exposed to two-way ANOVA at Randomized Block Design for testing year and districts fixed effects handled in the survey. Mean separation for district effect was performed using Duncan multiple comparison test at 1% significance level. To measure the effectiveness of two-way ANOVA, coefficient of determination (R2%) and adjusted coefficient of determination (Adjusted R2 %) were estimated. All the statistical evaluations were made through SPSS 20 software program.

The survey of the larvae parasitoids of S. temperatella in cereal fields in Northern Cyprus revealed the presence of two braconid species; Bracon (Habrobracon) stabilis (Wesmael, 1838) and Agathis gracilenta Tobias, 1963. Bracon hebetor is the most common species. Whereas, A. gracilenta was identified for the first time as a larval parasitoid of S. temperatella in Northern Cyprus. In previous studies recorded the larvae parasitoid species; including Pnigalio pecticornis (Linnaeus, 1758) (Hym.: Ichneumonidae) (Kaya, 1975), Bracon stabilis Wesmael and Apanteles sp. (Hym.: Braconidae) (Gözüaçık et al., 2008) in Turkey; Anilastus sp. Förster (Hym.: Ichneumonidae) (Al-Zyoud, 2007) in Jordan; Diglyphus chabrias Walker and Necremnus tidius Walker (Yefremova et al., 2007) and Sympiesis euspilapterygis (Erdos) (Hym.: Eulophidae) in Iran (Pirhadi et al., 2008; Talebi et al., 2011).

The number of larvae and parasitism rates in cereal fields where the studies were conducted in Northern Cyprus in the years 2012 and 2013 are given in Tables I and II, respectively. As also understood from Tables I and II, It was observed that the highest rates of parasitism 54.3% and 53.8% were recorded in barley fields of Akçay and Aydınköy (Güzelyurt) in 2012 and Ağırdağ (Girne) in 2013, respectively. No parasitoids were encountered at Güneşköy (Güzelyurt) and Boğaziçi (İskele) in the year 2012 and Boğaziçi and Güvercinlik (Gazimağusa) in the year 2013.

Parasitism rates (the arcsin transformed parasitism rates) in cereal fields of Northern Cyprus in the years 2012-2013 are given in Table III.

Table III illustrates the results of ANOVA performed for testing the effects of district and year factors on the arcsin transformed parasitism rates examined in the survey. Both coefficient of determination (R2 %) and adjusted coefficient of determination (Adjusted R2 %) reflected that nearly all of the variability in transformed parasitism rate was explained by district (P<0.01) and year (P<0.01) effects, which were found very significant in the survey. On the other hand, the result revealed that these two main effects were significant sources of variation.

Table IV.- Average parasitism rates (the transformed rates) of Syringopais temperatella in cereal fields in Northern Cyprus during the year 2012-2013.

A, B, the difference between the averages of two years with different letter is significant at 1% level; a, b, c, the difference between the averages of two locations with different letter is significant at 1% level.

Average parasitism rates and their arcsin transformed rates on S. temperatella in cereal fields in Northern Cyprus in the years 2012-2013 are given in Table IV. The significantly difference between the years 2012 and 2013 was found for the transformed parasitism rate and the average transformed rate in the year 2012 was remarkably higher than that in the year 2013 (P<0.01). The highest values in the transformed parasitism rate were obtained from Güzelyurt and İskele districts, which were similar to each other, statistically, whereas the lowest transformed rate was recorded in Gazimağusa district, which was lower compared to Girne and Lefkoşa districts.

As shown in Table IV, the highest rates of parasitism were recorded in the year 2012 compared with that in the year 2013. Highest rates of parasitism were recorded at Güzelyurt (Morphou) district in both years (35.78 and 25.18%) while the lowest were at Gazimağusa (Famagusta) district (17.95 and 7.71%) (Table II). In Jordan, Al-Zyoud (2007) reported that parasitism rate was 49.0% created by Anilastus sp. In Turkey, the parasitism rate was determined to be 8-10% in the years 2005-2006 (Gözüaçık et al., 2008). It was seen that parasitism rates varied from year to year and from location to location. It is thought that every part of Güzelyurt and in some parts of Iskele districts have more trees, weeds and, polycultures on the basis of irrigation (citrus, potatoes, kolokas (Taro), artichokes etc.) causing to higher parasitism rate in comparison with Lefkoşa and Gazimağusa districts. Thus, semi-natural habitats provide natural enemies with prey and alternative hosts of pests having nutritional plant resources and together with shelter and overwintering sites (Médiène et al., 2011). Secondly, chemical insecticides used intensively by the cereal growers against S. temperatella might negatively affect the parasitoids population. For this reason, the chemical insecticides used against this pest should be of the least harmful or harmless class. In addition, the application of insecticides at the recommended doses and on time is of great importance.

We are grateful to Prof. Dr. Ahmet Beyarslan (Faculty of Science and Literature, Department of Biology, Bitlis Eren University, Bitlis, Turkey) for identifying the specimens.

The authors declare no conflict of interest.