Abdurrahman Ayvaz

Insecticidal Activity of the Essential Oils from Different Plants Against Three Stored-Product Insects

Abstract This study was conducted to determine the insecticidal activity of essential oils from oregano, Origanum onites L. (Lamiales: Lamiaceae), savory, Satureja thymbra L. (Lamiales: Lamiaceae), and myrtle, Myrtus communis L. (Rosales: Myrtaceae) against three stored-product insects. Essential oils from three species of plants were obtained by Clevenger-type water distillation. The major compounds in these essential oils were identified using gas chromatography-mass spectrometry and their insecticidal activity was tested against adults of the Mediterranean flour moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), the Indian meal moth Plodia interpunctella Hübner (Lepidoptera: Pyralidae) and the bean weevil Acanthoscelides obtectus Say (Coleoptera: Bruchidae). While the major compound found in oregano and savory was carvacrol, the main constituent of the myrtle was linalool. Among the tested insects, A. obtectus was the most tolerant species against the essential oils. However, the insecticidal activity of the myrtle oil was more pronounced than other oils tested against A. obtectus adults. The essential oils of oregano and savory were highly effective against P. interpunctella and E. kuehniella, with 100% mortality obtained after 24 h at 9 and 25 µl/l air for P. interpunctella and E. kuehniella, respectively. LC50 and LC99 values of each essential oil were estimated for each insect species.

Gamma radiation sensitivity of the eggs, larvae and pupae of Indian meal moth Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)

BACKGROUND This study focused on determining the minimal effective gamma radiation dose that prevents commodity damage caused by the Indian meal moth Plodia interpunctella (Hübner). The study was also designed to assess the effect of releasing either partially sterilized males alone or both partially sterilized males and females on the reproductive potential of P. interpunctella populations. RESULTS The dose of radiation required to prevent larval emergence from irradiated eggs was 350 Gy, and the same dose was also required to prevent adult emergence from mature larvae. A dose of 300 Gy was not able to prevent adult emergence from irradiated pupae. The dose at which 100% sterility was achieved in treated females mated to treated males was 300 Gy for the parental generation of irradiated pupae. Fertility of the parental males from irradiated pupae was 48.17% at 300 Gy in treated males crossed with untreated females, but male progeny of irradiated male parents had a residual fertility of 11.06% at the same dose. CONCLUSION F(1) males from irradiated pupae were more sterile than parental males. To prevent larval emergence from irradiated eggs, a dose of 350 Gy is required. The same dose is required to prevent the larvae from reaching the adult stage.

Chemical Composition and Fumigant Toxicity of Some Essential Oils Against Ephestia kuehniella

ABSTRACT The chemical constituents of some essential oils extracted from aromatic plants (savory, Satureja thymbra L.; Turkish oregano, Origanum onites L.; myrtle, Myrtus communis L.; marjoram, Origanum majorana L.; laurel, Laurus nobilis L.; lemon, Citrus limon L.; sticky goosefoot, Chenopodium botrysh L.; and tansy, Tanecetum armenum [DC] Suchultz Bip.) were analyzed by gas chromatographymass spectrometry. Fumigant toxicity of volatile compounds was tested against Mediterranean flour moth, Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae), eggs and adults. Percentage of mortality and longevity of E. kuehniella adults were estimated after essential oil treatments. LC50 and LC99 values were determined for each exposure time for each essential oil. Marjoram and lemon oils were the most effective of all the essential oils tested. The major components were linalool, 1.8-cineole, citral, 2-(4a.8-dimethyl-1.2.3.4.4a.5.6.7-octahydro-naphthalen-2-yl)-prop-2-en-l-ol, and p-cymene for marjoram, laurel, lemon, goosefoot, and tansy, respectively. The LC50 and LC99 values were estimated as 3.27 and 5.13 µl liter-1 air for marjoram and 4.05 and 5.57 µl liter-1 air for lemon essential oils at the longest exposure time. Decreasing longevity effect of marjoram and lemon was more prominent compared with other essential oils. We suggest that essential oils obtained from certain aromatic plants have potential as fumigants for stored product pests.

The synergic and antagonistic activity of Cry1Ab and Cry2Aa proteins against lepidopteran pests

Cry1Ab and Cry2Aa were overexpressed in Escherichia coli BL21(DE3), and their proportions were determined for evaluating their synergic and antagonistic interactions on Ephestia kuehniella and Plodia interpunctella. Results indicated antagonistic interaction on both lepidopteran pests, and it was concluded that 1 : 1 combination of Cry1Ab:Cry2Aa should be avoided in control programmes for these larvae.

Native entomopathogenic nematodes isolated from Turkey and their effectiveness on pine processionary moth, Thaumetopoea wilkinsoni Tams

Two native entomopathogenic nematodes were isolated from soil samples in Eastern Mediterranean region of Turkey and characterized based on 28S rDNA region. BLASTN homology and phylogenetic analysis of SK17 and SK-71 isolates indicated 98% and 99% identity to Steinernema affine and Steinernema feltiae, respectively. The results were constructed by neighbour-joining and bootstrap tree methods. Efficacy of S. affine (SK-17 strain) and S. feltiae (SK-71 strain) was tested against the larvae of pine processionary moth, Thaumetopoea wilkinsoni Tams, and remarkable mortality rates were obtained. Both strains caused complete mortality upon application of 500 IJs in foliar tests. However, the same strains caused 30% and 33% mortality at 80 IJs/cm2 in soil applications. It was concluded that these native strains could be considered as potential biocontrol agents for reducing the damage caused by T. wilkinsoni larvae.

Expression of cry1Ab gene from a novel Bacillus thuringiensis strain SY49-1 active on pest insects

In this study, the cry1Ab gene of previously characterized and Lepidoptera-, Diptera-, and Coleoptera-active Bacillus thuringiensis SY49-1 strain was cloned, expressed and individually tested on Ephestia kuehniella (Lepidoptera: Pyralidae) and Plodia interpunctella (Lepidoptera: Pyralidae) larvae. pET-cry1Ab plasmids were constructed by ligating the cry1Ab into pET28a (+) expression vector. Constructed plasmids were transferred to an Escherichia coli BL21 (DE3) strain rendered competent with CaCl2. Isopropyl β-d-1-thiogalactopyranoside was used to induce the expression of cry1Ab in E. coli BL21(DE3), and consequently, ∼130 kDa of Cry1Ab was obtained. Bioassay results indicated that recombinant Cry1Ab at a dose of 1000 μg g−1 caused 40% and 64% mortality on P. interpunctella and E. kuehniella larvae, respectively. However, the mortality rates of Bt SY49-1 strains’ spore–crystal mixture at the same dose were observed to be 70% on P. interpunctella and 90% on E. kuehniella larvae. The results indicated that cry1Ab may be considered as a good candidate in transgenic crop production and as an alternative biocontrol agent in controlling stored product moths.

Effects of Bacillus thuringiensis subsp. kurstaki HD1 spore-crystal mixture on the adults of egg parasitoid Trichogramma evanescens (Hymenoptera: Trichogrammatidae)

In the present study, the potential hazard of Bacillus thuringiensis (Bt) kurstaki HD1 spore-crystal mixture (spore/δ-endotoxin) on parasitization performance and longevity of female egg parasitoid Trichogramma evanescens Westwood was evaluated. For this purpose, Bt kurstaki HD1 was incubated at 30 °C in T3 medium at 200 rpm for seven days. Lyophilized spore-crystal mixture (5000 µg mL−1) was mixed with 50% honey solution and supplied to 0–24 h old T. evanescens adults as a nutrient to ensure the ingestion of the toxins by the parasitoids. The results indicated that spore-crystal mixture of Bacillus thuringiensis subsp. kurstaki (Btk) HD1 did not induce considerable decrease in parasitization performance and longevity of T. evanescens adults. Thus, it can be concluded that Btk HD1 products can safely be used together with egg parasitoid T. evanescens in integrated pest management system to compensate the deficiency of each control tactic alone.

Ionizing Radiation Disinfestation Treatments against Pest Insects

Pesticides are often considered a suitable solution for controlling pests. However, the use of chemicals is very costly, and their residues have always the potential to pollute soil, air, and ground water and also pose significant risks to the natural ecosystems and nontarget organisms. Considering all these, irradiation could offer substantial and charming option for eliminating the export commodity fumigation uses for the undesirable effects of chemicals. Gamma rays, high-energy electrons, and X-rays are among the ionizing radiation sources utilized practically in sterile insect releasing programs using “self-contained” and “non-self-contained or panoramic” irradiators. When applying radiation sources, dosimetry should be adjusted to ensure quarantine security for large groups of insect pests. Because of growing concerns related to health problems and environmental pollutions, chemical sanitizing treatments are faced with a lot of regulatory restrictions, so irradiation reveals best choice for this purpose. The sterile insect technique (SIT) may have indispensable consideration for integrated pest management (IPM) of many important insect pests, including agricultural, veterinary, and medicinal importance. On the other hand, to overcome the obstacles of SIT treatments, genetic engineering techniques were supposed to ease the devel‐ opment of transgenic insects for sustainable tactics to control pest populations. Thus, genetic means should be an integral part of SIT treatments in controlling important pest populations.