Abstract:The essential oil of aerial parts of Agastache foeniculum (Lamiaceae) was isolated by hydrodistillation method and constituents of oil were analyzed by gas chromatography mass spectrometry (GC-MS) method. Methyl chavicol, 1,8-cineole, 1-octen-3-ol, A. foeniculum could be applicable the management of population of stored-product beetle pest.

Plant secondary metabolites play an important role in plant-insect interactions and therefore such compounds may have insecticidal activity against insects. The chemical composition of the essential oil from leaves and flowers of Lavandula stoechas grown in Kashan, Iran, was studied by gas chromatography mass spectrometry (GC-MS). 1,8-Cineole (7.02%), γ-Cadinene (5.33%), T-Cadinol (5.07%), p-Mentha-1-en-8-ol (5.02%) and Caryophyllene (5.01%) were found to be the major constituents of the oil. In fumigant toxicity tests with the essential oil against adults of Tribolium castaneum Herbst, Lasioderma serricorne F. and Rhyzopertha dominica F. at 27±1°C and 60±5% RH, it was observed that L. serricorne (LC 50 = 3.835 µl/l) were significantly more susceptible than R. dominica (LC 50 = 5.66 µl/l) and T. castaneum (LC 50 = 39.685 µl/l) 24 h after treatment. In all cases, considerable differences in mortality of insects to essential oil vapor were observed with different concentrations and times. Mortality increased as the doses of essential oils and exposure period increased and after 72 h fumigations, greatest percentages of mortality were obtained. The findings indicate the strong insecticidal activity of L. stoechas oil and it may be used in grain storage against insects L. serricorne, R. dominica and T. castaneum.

The susceptibility status of Colorado potato beetle, Leptinotarsa decemlineata (Say), adults to phosalone was determined by dip and glass jar assay techniques. Bioassay results indicated a narrow variation in Colorado potato beetle insecticide susceptibility among sample sites. LC50 values were generally highest from specimens collected in field that received frequent phosalone applications for seven consecutive growing seasons. In five populations tested, LC50 values ranged from 503.72 to 827.95 ppm in dip test method. In glass jar technique, resistance ratio value of 1.72 for LC50 was obtained. A significant linear relationship between LC50 values of individual populations across test methods was detected. Both bioassay techniques were suitable for monitoring resistance to insecticide in Colorado potato beetle adult populations. Glass jar technique, however, exhibited less variability in LC50 estimates and showed a higher degree of sensitivity than the dip method. Filter paper and leaf disk techniques for larvae were two bioassay methods used to determine phosalone susceptibility in L. decemlineata populations. Both bioassay techniques exhibited a similar level of susceptibility of the larvae to phosalone; however, the fiducial limit values from filter paper method were narrow than the leaf disk assay technique. A significant direct relationship between LC50 values of individual population across test methods was observed. Differences in LC50 ranking among fields between adults and larvae indicated a differential susceptibility to insecticide between life stages. Low LC50 values obtained from Colorado potato beetle in sample sites indicated that phosalone resistance was not severe in these fields. The glass jar and filter paper testing methods are simple and sensitive test techniques for measuring susceptibility of Colorado potato beetle adults and larvae to phosalone, respectively.

This survey investigated the relationship between gall morphology and some fitness components in the asexual generation of Cynips quercusfolii L. (Hymenoptera: Cynipidae). Results showed that larger C. quercusfolii galls were formed on the south side of oak trees Quercus infectoria Olivier (Fagales: Fagaceae). Larval chamber diameter in the gall was similar, but gall diameter and gall wall thickness varied with the location of the gall on the tree. Cynips quercusfolii was attacked by parasitoids, and the south-facing galls suffered significantly lower parasitoid attacks. Thickness of gall walls and parasitism rate were negatively correlated. Mean gall diameter and gall wall thickness were significantly larger in south-facing galls than other directions, but the difference in the mean larval chamber diameter was not significant. These results suggest that the position of galls on the tree affected gall wall thickness, and this plays an important role in parasitoid attacks. These results suggest that C. quercusfolii prefer to attack the south side of oak trees, and selection of this side by wasps led to formation of larger galls with thick walls that decreased parasite attack, which will affect growth and survival of wasp larvae.

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