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

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

Recombinant entomopathogenic agents: a review of biotechnological approaches to pest insect control

Although the use of chemical pesticides has decreased in recent years, it is still a common method of pest control. However, chemical use leads to challenging problems. The harm caused by these chemicals and the length of time that they will remain in the environment is of great concern to the future and safety of humans. Therefore, developing new pest control agents that are safer and environmentally compatible, as well as assuring their widespread use is important. Entomopathogenic agents are microorganisms that play an important role in the biological control of pest insects and are eco-friendly alternatives to chemical control. They consist of viruses (non-cellular organisms), bacteria (prokaryotic organisms), fungi and protists (eukaryotic organisms), and nematodes (multicellular organisms). Genetic modification (recombinant technology) provides potential new methods for developing entomopathogens to manage pests. In this review, we focus on the important roles of recombinant entomopathogens in terms of pest insect control, placing them into perspective with other views to discuss, examine and evaluate the use of entomopathogenic agents in biological control

Ovicidal activity of microwave and UV radiations on mediterranean flour moth Ephestia kuehniella Zeller, 1879 ( Lepidoptera: Pyralidae)

Insecticidal activity of microwave and ultraviolet radiation (UV) on E. kuehniella, 1879 (Lepidoptera: Pyralidae) eggs were investigated. Eggs (<= 24 h) were exposed to microwave and UV radiation at different time periods. Microwave radiation was applied at the powers of 150, 360, 430, and 600 W for different exposure times (10-300 s). It was evident that increasing power and exposure times caused increasing mortality on the eggs and accordingly larval emergence decreased. Complete mortality was achieved at the power of 150 W and the longest exposure time (300 s). The same result was achieved at the highest dose (600 W) and the shortest exposure time (10s). When the eggs were treated with the highest power of microwave radiation used, the lethal times were estimated as, 2.61 (LT(50)) and 7.34 s (LT(99)). Similarly short (254 nm) and long-wave UV (365 nm) radiations also decreased the larval emergence from E. kuehniella eggs depending on increasing time periods. The highest period of UV treatment (300 s) caused 92.20% and 28.89% egg mortality at 254 and 365 nm, respectively. The lethal times, LT(50) and LT(99) for short wave UV radiation were estimated to be 155.68 and 418.068 s, respectively

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

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 botrys L.; and tansy, Tanecetum armenum [DC.] Suchultz Bip.) were analyzed by gas chromatography-mass 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. LC(50) and LC(99) 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-1-ol, and p-cymene for marjoram, laurel, lemon, goosefoot, and tansy, respectively. The LC(50) and LC(99) values were estimated as 3.27 and 5.13 mu l liter(-1) air for marjoram and 4.05 and 5.57 mu l 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

FUNGI ASSOCIATED WITH FREE-LIVING SOIL NEMATODES IN TURKEY

Free-living soil nematodes have successfully adapted world-wide to nearly all soil types from the highest to the lowest of elevations. In the current study, nematodes were isolated from soil samples and fungi associated with these free-living soil nematodes were determined. Large subunit (LSU) rDNAs of nematode-associated fungi were amplified and sequenced to construct phylogenetic trees. Nematode-associated fungi were observed in six nematode strains belonging to Acrobeloides, Steinernema and Cephalobus genera in different habitats. Malassezia and Cladosporium fungal strains indicated an association with Acrobeloides and Cephalobus nematodes, while Alternaria strains demonstrated an association with the Steinernema strain. Interactions between fungi and free-living nematodes in soil are discussed. We suggest that nematodes act as vectors for fungi

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 crylAb into pET28a (+) expression vector. Constructed plasmids were transferred to an Escherichia coli BL21 (DE3) strain rendered competent with CaCl2. Isopropyl beta-D-1-thiogalactopyranoside was used to induce the expression of cry1Ab in E. coli BL21(DE3), and consequently, similar to 130 kDa of Cry1Ab was obtained. Bioassay results indicated that recombinant Cry1Ab at a dose of 1000 mu g 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 crylAb may be considered as a good candidate in transgenic crop production and as an alternative biocontrol agent in controlling stored product moths. (C) 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. This is an open access article under the CC BY-NC-ND licens

Chemical Composition, Antibacterial and Insecticidal Activities of the Essential Oil from the Pistacia terebinthusL. Spp. Palaestina (Boiss.) (Anacardiaceae)

WOS: 000337612900010Essential oil (EO) was hydrodistillated using a Clevenger-type apparatus and chemically determined using gas chromatography (GC) and GC/mass spectrometry. The analysis of the EO from the leaves of the Pistacia terebinthus has indicated that -pinene (19.97%), sabinene (15.43%), -pinene (8.57%) and terpinen-4-ol (9.65%) are the major compounds of the oil in concern. In the antibacterial disc diffusion assay, EO revealed a broad spectrum activity on the growth of both gram-positive and gram-negative bacteria when compared with the standard antibiotics. Likewise, in the insecticidal assay, significant activity was observed on two important pest insects, Acanthoscelides obtectus and Tribolium castaneum. A 100% mortality was found at 160L/L air dose for T.castaneum at 48-h and A.obtectus at 72-h exposure periods, respectively. Practical Applications Various parts of the Pistacia terebinthusL. belonging to the Anacardiaceae family are edible and contribute significant benefits with invaluable potentialities to the Mediterranean life. Leaves of this tree are consumed as either fresh or cooked. The biological potential of the essential oil (EO) from the leaves of P. terebinthusL. grown in the Eastern Mediterranean region has not been assessed so far. The present assays indicated that the EO of P.terebinthus contains bioactive compounds against bacteria and pest insects suggesting its potential use in food processing and preservation.Scientific Research Project (Osmaniye Korkut Ata University-BAP, Osmaniye, Turkey)Osmaniye Korkut Ata UniversityThis study was supported in part by the Scientific Research Project (Osmaniye Korkut Ata University-BAP, Osmaniye, Turkey). Authors would like to express their many thanks to Assoc. Prof. Abdurrahman Ayvaz for supplying the insect cultures and providing a place for the insecticidal assay in the Biology Department of Science and Arts Faculty, Erciyes University (Kayseri, Turkey)

Characterization of Local Bacillus thuringiensis Isolates and Their Toxicity to Ephestia kuehniella (Zeller) and Plodia interpunctella (Hubner) Larvae

Putative Bacillus thuringiensis isolates were obtained from soils of various agricultural fields. Of all the tested isolates U14.1, U14.2 and U14.5 were found to be positive for cry1C. Besides, U6.6, U14.1, U14.4 and U14.5 were determined to contain cry1B. These local isolates produced bi-pyramidal, spherical and cubical crystal proteins. U14.1, U14.4 and U14.5 isolates exhibited similar protein banding patterns with Btk producing around 45, 70 and 130 kDa proteins. However, U14.2 and U6.6 produced only 60 kDa major protein band. Some of the isolates also produced bands less than 45 kDa showing the presence of some other low molecular weight proteins. The results of this study demonstrated that isolates of Bt obtained from various agricultural fields may display toxicity against Ephestia kuehniella (Zeller) and Plodia interpunctella (Hubner) larvae. As a result, spore-crystal mixture of these isolates may play an important role in reducing the damage to stored products caused by these important pest insects

A novel Bacillus thuringiensis strain and its pathogenicity against three important pest insects

A highly pathogenic Bacillus thuringiensis (Bt) strain was isolated from a soil sample in Turkey and characterized in terms of both its 16S-ITS rDNA region and cry gene content. This strain (SY49.1) harboured several cry genes producing crystalline inclusions known to have toxicity on lepidopteran, dipteran and coleopteran pests. The 16S-ITS sequence analysis of Bt SY49.1 showed 98% similarity to Bt serovar andalousiensis BGSC 4AW1. The larvae of Ephestia kuehniella and Plodia interpunctella were treated with a spore-crystal mixture of this strain in the dose range of 50-1000 mu g g(-1). Mortality rates were higher than 90% at the highest concentration for these pests. For Tribolium castaneum much higher concentrations were needed than with lepidopteran pests larvae. At the highest concentration tested of 10 mg g(-1), about 62% mortality was obtained. It was concluded that this native strain of Bt could be used as an effective biocontrol agent against various lepidopteran pests. (C) 2012 Elsevier Ltd. All rights reserved