Although most ecologists agree that both top-down and bottom-up forces (predation and resource limitation, respectively) act in concert to influence populations of herbivores, it has proven difficult to estimate the relative contributions of such forces in terrestrial systems. Using a combination of time-series analysis of population counts recorded over 16 years and experimental data, we prese...

Background The defoliation of oaks is an urgent problem for forestry in Central Europe. During the last outbreak of the green oak leaf roller(Tortrix viridana) in 2003-2005, we observed fundamental differences in the defoliation level of individual Quercus robur trees in Germany. Some of the trees seem to be somehow “tolerant” (T oaks) against the insects grub while some seem to be conspicuousl...

In a recent article, Hunter uses the late George Varley and George Gradwell's long-term data on the winter moth (Operophtera brumata) and green tortrix (Tortrix viridana) populations to propose a method of quantifying the relative importance of top-down effects (because of natural enemies) and bottom-up effects (because of resource competition) in influencing population dynamics. We believe thi...

(3E,5Z)-3,5-dodecadienyl acetate was identified by Unelius C.R. et al. as the sex pheromone of the leafroller Bonagota cranaodes (Lepidoptera: Tortricidae), an economically important insect pest of apples in Southern Brazil. In order to elucidate the pheromone structure this compound was first prepared by a methodology in low stereoselectivity and yield. Recently a concise synthesis was reporte...

Female obliquebanded leafrollers, Choristoneura rosaceana (Harris), collected from Oregon,Michigan, andNewYorkwere deployed in delta traps inMichigan apple orchards to compare their relative attractiveness to Michigan males of the same species. Females originating from Oregon attracted more males than females originating from New York during both generations of leafroller ßight in Michigan. Als...

abstract the oak leafroller moth , tortrix viridana l. is a destructive pest within it’s spreading area which invades the oak species, especially in west and northwest forests of iran, in recent years. some parts of west azarbayjan’s forests which are located in piranshahr and sardasht region have been affected by this pest since 1989 that oak trees vigor and survival have been gone down result...

Foliage damage by leaf-eating insects during mass reproduction causes deterioration of the sanitary state forest and a decrease in its increment. Timely detection pest foci allows reducing cost their elimination preventing negative consequences for stands. The purpose this study was to identify species composition on territory State Enterprise Zhytomyrske Forestry subcompartments with greatest ...