Yozgat ili buğday ekim alanlarında süne, Eurygaster Spp. (Hemıptera: Scutellerıdae)'nin farklı buğday çeşitleri üzerindeki populasyon yoğunluğu, zararı ve yumurta parazitlenme oranlarının belirlenmesi

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Thesis Type: Doctorate

Institution Of The Thesis: Hatay Mustafa Kemal University, Fen Bilimleri Enstitüsü, Bitki Koruma (Yl) (Tezli), Turkey

Approval Date: 2025

Thesis Language: Turkish

Student: HATİCE ASİL

Supervisor: Nihat Demirel

Open Archive Collection: AVESIS Open Access Collection

Abstract:

This study was carried out between 2021 and 2024 in the wheat-growing areas of Yozgat province to assess the population density, damage, and egg parasitism rates of the Sunn pest, Eurygaster spp. (Hemiptera: Scutelleridae) across different wheat varieties. Spring overwintering surveys indicated that the percentage of live overwintered sunn pests increased from 0.60% in 2021 to 1.30% in 2023 and remained high at 1.19% in 2024, while mortality decreased from 0.23% to 0.14%, highlighting an increased risk from surviving individuals. Assessment of Sunn pest and surveys of nymphs and adults showed that values obtained using the 100-sweep-net method were low, whereas the 40-frame method provided more reliable and consistent population estimates. Egg parasitism rates declined from 33.1% in 2021 to 20.9% in 2023, indicating that although the absolute number of parasitized eggs may rise, their proportion relative to total eggs is decreasing, potentially reducing the effectiveness of biological control. Observations of stem and white awn damage revealed increases over the period, with white awn damage more prevalent than the stem damage. Grain sucking damage fluctuated at moderate levels, with a three-year average of 0.67%. Autumn overwintering surveys indicated that the pest population remained relatively stable in terms of both alive and dead individuals. Overall, the sunn pest population has posed a high agricultural risk in recent years. While the sweep-net method tends to underestimate population density, the frame method provides more accurate and reliable results. The decline in parasitism suggests a potential reduction in the effectiveness of natural control agents. Consequently, regular monitoring of sunn pest populations, prioritizing frame-based observations, the effective use of early warning systems, and the implementation of integrated pest management strategies are crucial for minimizing crop damage and maintaining sustainable agricultural production.