جستجوی مقالات مرتبط با کلیدواژه « سوسک برگ خوار نارون » در نشریات گروه « گیاهپزشکی »

Elm leaf beetle is one of the most important pests of Elm trees at adult stage and especially at larval stages. In this research work, the contact toxicity and nutritive indicators of Cinnamon, Peppermint, and Eucalyptus have been investigated. The experiments were performed in five densities with three repetitions for each essential and for each life stage of the elm leaf beetle at 25±1C0 and relative humidity of 60±5 percent for 16 hours in daylight and 8 hours in darkness in vitro. The results obtained from biometry data showed that with an increase in density of the essential oils, the mortality rate of elm leaf beetle at different stages of their life increased for all the three essential oils. Based on these results, the essential oil of Cinnamon proved to have the most effect at different stages of elm leaf insect by creating 80 percent mortality relative to the two essential oils of eucalyptus and peppermint after 24 hours. Furthermore, with an increase in the density of the essential oils, the nutritive indicators at the second. instar larva were also reduced. Statistical analysis of variance showed that the relative rate of second instar larva (PCR) in cinnamon essential oil in three concentrations of LC25, LC35 and LC50 compared with the control group was more meaningful compared with the two other essential oils at 5 percent and nutrition inhibition was positive for all the essential oils especially for cinnamon essential oil.  The findings indicate that Cinnamon essential oil compared to Peppermint, and Eucalyptus essential oils is a more suitable candidate to control this pest.

In current study, pathogenicity of two pathogenic fungi, Beauveria bassiana Vuellemin and Metarhizium anisopliae Sorokin were assessed on adults of elm leaf beetle, Xanthogaleruca luteola with four concentrations 105, 106, 107 and 108 spore/ml and control treatment using immersion and spraying methods. The experiments were conducted at controllable conditions, 25±1°C, 75±5% RH and photoperiod 12:12 h in growth chamber. Mortality rate in both methods in all treatments were recorded during 10 days. The values of LC50 and LC90 for B. bassiana were 2.7×106 and 7.72×106 spore/ml in immersion method and were 7.75×106 and 35.05×106 spore/ml in spraying method while these values for M. anisopliae were 2.68×106 and 7.99×106 spore/ml in immersion method and were 8.36×106 and 46.8×106 spore/ml in spraying method, respectively, it shown higher pathogenicity of B. bassiana in comparison with M. anisopliae. The lowest LT50 and LT90 for B. bassiana at concentration 108 spore/ml were 3.39 and 13.12 days while these values for M. anisopliae were 4.51 and 15.03 days respectively. The result shows that B. bassiana in both methods immersion and spraying causes more mortality during shorter time compare to M. anisopliae. According to findings of the current study, both fungi B. bassiana and M. anisopliae can be used in integration with other non-chemicals method for control of elm leaf beetle.

New formulations of botanical insecticides have been developed as an effective and safe compound alternative to synthetic pesticides. Application of nanoencapsulated formulations of pesticides enhance efficiency, quality and controlled release of these substances. In this research, insecticidal activity of essential oil of wormwood sagebrush Artemisia sieberi Besser was investigated on various stages of elm leaf beetle Xanthogaleruca luteola (Müller). The experiments were conducted at 25 ± 2 °C, 65 ± 5% RH and a photoperiod of 16: 8 h (L: D). The formulated essential oil was sprayed on leaves and insects simultaneously. The LC50 value of the formulation was 5279, 3939 and 5169 ppm for eggs, larvae and adults, respectively. Treatment of leaves by nanoencapsulated oil at 3000 ppm caused significant reduction at larval stage compared to control. Our findings suggest that the use of nanoencapsulated essential oil can be effective in the management of elm leaf beetle.

The elm leaf beetle، Xanthogaleruca luteola (Muller)، is one of the most destructive pests of elm trees that overwinters as diapausing adult. The main cryoprotectants and their seasonal fluctuations in the elm leaf beetles were analyzed based on the monthly level of polyhydric alcohol from October 2008 through June 2009، using high performance liquid chromatography (HPLC). The compounds myo-inositol، trehalose، glucose and glycerol were found to be the most important polyols in the overwintering adults، of which myo-inositol content exhibited an inversely significant correlation with temperature fluctuations (r = -0. 814، P = 0. 014). The highest level of myo-inositol was observed in December (32. 6 ± 2. 7 µmol g-1 fresh body weight)، while its lowest level was recorded in April (3. 0 ± 0. 4 µmol g-1 fresh body weight). The total concentration of all cryoprotectants was 100. 7 ± 7. 6 µmol g-1 fresh body weights in January. The results underline the influential role of myo-inositol، trehalose and glucose compounds in enhancing the cold tolerance of elm leaf beetles and their chance of survival during freezing winter days.