Akademik Veri Yönetim Sistemi
Tezin Türü: Doktora
Tezin Yürütüldüğü Kurum: Erciyes Üniversitesi, Fen Bilimleri Enstitüsü, --, Türkiye
Tezin Onay Tarihi: 2022
Tezin Dili: İngilizce
Öğrenci: ESRAA MAHDI SALEH AL-OBAIDI
Asıl Danışman (Eş Danışmanlı Tezler İçin): Ali İrfan İlbaş
Eş Danışman: Semih Yılmaz
Özet:
ABSTRACT
This study aimed to determine the effects of local Bacillus thuringiensis (Bt) strains and
their Cry proteins on the larvae of the fall webworm insect, Hyphantria cunea. Six
strains of Bt were used: Bt SY49.1, Bt SY25.1, Bt SY33.3, Bt SY56.3, Bt SY27.1 and
standart strain Bacillus thuringiensis var kurstaki (Btk). The larvae of the insect
Hyphantria cunea used in this study were collected from the Rize region of
Northeastern Turkey. Seven doses were determined for each strains according to the
concentrations added: 10 μg/ml, 50 μg/ml, 100 μg/ml, 250 μg/ml, 500 μg/ml, 1000
μg/ml, 2250 μg/ml. Larvae of different ages were exposed to Bt strains’ products.
Larval mortality was monitored for ten days, and the number of dead larvae and live
larvae were recorded. The results showed that the mortality rate of Hyphantria cunea
larvae increased with the progression of time and increment of doses in strains of Bt that
were applied. The results showed that the highest LD50 value was obtained from the Bt
SY56.3 strain, while the lowest value was obtained from Bt SY49.1 strain. Moreover,
the highest value for LD99 was obtained after using Bt SY33.3 products, while the
lowest value was achieved after Bt SY49.1 treatment. Also, Bt SY56.3 showed lower
mortality rates compared to the other strains, while Bt SY27.1 and Bt SY49.1 showed
higher mortality rates among the strains used. The effect of mixture of spores for the
three strains ( Bt SY49.1, Bt SY27.1and Btk) also showed the highest mortality rate was
Bt SY49.1, while Btk showed lower mortality rate. On the third stage of the larvae (L3),
there was a higher average mortality rate for Bt SY27.1 with the crystal and spore-
crystal, and a lower average mortality rate for Btk with the crystal. In the fourth stage of
the larvae (L4), the mean mortality was higher for Bt SY49.1 with the spore-crystal
mixture, while the mean mortality was lower than Btk with the spore-crystal, Cry vii
proteins and spore-crystal mixtures, it can be concluded that it has potential effects on
all larval stages, including early and advanced larval stages of Hyphantria cunea. Also,
the extracted Cry proteins and spores of Bt strains have considerable lethal toxicity on
the third (L3) and forth (L4) larvae of Hyphantria cunea. The result of this study
indicated that spore and Cry proteins of the local Bt strains have lethal effects on
Hyphantria cunea larvae.
Keywords: Biocontrol, Hyphantria cunea, Bacillus thuringiensis, Btk, Cry protein,
Sustainable agriculture