Türkiye’de ipekböceği Bombyx mori L., 1758 (Lepidoptera: Bombycidae)’nin Bursa Beyazı ırkında Aspergillus flavus Link (Eurotiales: Aspergillaceae)’un görülmesi: İzolasyon, karakterizasyon ve patojenitesi

Öz

İpekböceği, Bombyx mori L., 1758 (Lepidoptera: Bombycidae), Türkiye’de uzun yıllardır önemli bir gelir kaynağı olarak yetiştirilmektedir. Ancak mantar hastalıkları, ipekböceği yetiştiriciliği üzerinde yıkıcı etkiler yaratabilir. Ağustos 2024’te, İstanbul’da bir B. mori kültüründe çok sayıda sertleşmiş, ölü larva tespit edilmiş ve incelenmek üzere laboratuvara götürülmüştür. Mikroskobik incelemeler, enfeksiyon kaynağının küresel konidilere sahip bir mantar olduğunu ortaya koymuştur. Kültüre edilen mantardan DNA ekstrakte edilmiş ve ITS geni, dizisinin belirlenmesi amacıyla çoğaltılmıştır. Dizileme sonuçlarına göre mantar, Aspergillus flavus Link (Eurotiales: Aspergillaceae) olarak tanımlanmıştır. Filogenetik analizler, söz konusu izolatın Çin izolatlarına yakın olduğunu göstermiştir. Biyolojik testlerde, 5 farklı dozda A. flavus (1 × 10³ ila 1 × 10⁷ konidi/mL) 30 adet 5. dönem B. mori larvasına püskürtülmüştür. Uygulamanın 10. gününde en yüksek dozda (1 × 10⁷ konidi/mL) %100 ölüm gözlemlenmiştir. LD50 değeri 3.32 × 10³ konidi/mL olarak hesaplanmıştır. Aspergillus flavus, aspergillozise yol açması ve aflatoksin üretmesi nedeniyle hem B. mori hem de diğer organizmalar için ciddi bir tehdit oluşturmaktadır. Bu çalışma, Türkiye’de B. mori’de A. flavus enfeksiyonuna dair ilk kanıtı sunmakta ve larvaların bu mantara karşı oldukça duyarlı olduğunu göstermektedir. Bulgular, ipekböceklerinin sağlığını korumak ve ipek üretiminde sürdürülebilirliği sağlamak için sürekli izleme ve etkili antifungal kontrol stratejilerinin uygulanması gerektiğini vurgulamaktadır.

Anahtar Kelimeler

• Böcek patolojisi
• aspergilloz
• ipekböceği sağlığı
• ipekböcekçiliği

On the occurrence of Aspergillus flavus Link (Eurotiales: Aspergillaceae) on the Bursa white strain of the silkworm, Bombyx mori L., 1758 (Lepidoptera: Bombycidae) in Türkiye: Isolation, characterization, and pathogenicity

Abstract

The silkworm, Bombyx mori L., 1758 (Lepidoptera: Bombycidae) has been cultivated in Türkiye for many years as a valuable source of income. However, fungal diseases can have a devastating impact on silkworm farming. In August 2024, numerous hardened, dead silkworm larvae were discovered in a B. mori culture in Istanbul and subsequently taken to a laboratory for examination. Microscopic examination revealed that the source of the infection was a fungus with spherical conidia. DNA was extracted from the cultured fungus, and the ITS gene was amplified and sequenced. According to the sequencing results, the fungus was identified as Aspergillus flavus Link (Eurotiales: Aspergillaceae). Phylogenetic analyses showed that it was closely related to the Chinese isolates. In the bioassay, five doses of A. flavus (1 × 103 to 1 × 107 conidia/mL-1) were sprayed on 30 5th instar B. mori larvae. On the 10th day of application, 100% mortality was observed at the highest dose (1 × 107 conidia/mL-1). The LD50 was calculated to be 3.32 × 103 conidia/mL-1. Aspergillus flavus poses a significant threat to both B. mori and other organisms, as it causes aspergillosis and produces aflatoxin. This study provides the first evidence of A. flavus infection in B. mori in Türkiye, demonstrating that the larvae are highly susceptible to this fungus. The findings highlight the need for continuous monitoring and the implementation of effective antifungal control strategies to protect silkworm health and sustain sericulture productivity.

Keywords

• Insect pathology
• aspergillosis
• silkworm health
• sericulture

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