The main purpose of this paper has been to discuss the effects of psychological stress and other environmental factors on incidence of diseases. We were specifically concerned with stress that increased susceptibility of uninfected hosts when exposed to infection. If such stresses also reduced resources, fecundity and/or survivorship, there was a reduction in the host carrying capacity. In addi...

Surveys were carried out to determine species composition and host range of powdery mildews (Erysiphaceae) in Gilan province, Iran. Twenty seven taxa were identified. Among them Erysiphe circaeae, E. punicae, E. urticae, Microsphaera erlangshanensis, M. multappendicis, M. trifolii and Podosphaera clandestine/ var. cydonia are new to Iran. Parietaria officinalis and Phuopsis stylosa are new host...

as the host plants based on their physical and chemical characteristics can affect virulence of microbial control agents on the target pest and its natural enemies, therefore in the current study, the virulence of beauveria bassiana tv isolate at concentration 107 conidia/ml was evaluated against t. urticae female adults, on three different host plants; tomato, cucumber and strawberry. spray to...

The main purpose of this paper has been to discuss the effects of psychological stress and other environmental factors on incidence of diseases. We were specifically concerned with stress that increased susceptibility of uninfected hosts when exposed to infection. If such stresses also reduced resources, fecundity and/or survivorship, there was a reduction in the host carrying capacity. In addi...

In the present investigation, co-invasion of Lernaea parasite is reported in some fish species, collected from the Kor River Basin (Dorudzan Reservoir and Kor River), Southwest of Iran in 2010 and 2011.  Lernaea cyprinacea parasites were isolated from the external surface of eye, lips, gills, nostrils, fins, operculum and body of Alburnus mossulensis, Capoeta aculeata, Capoeta saadii (all nativ...

In 1909, several years before the famous `Organizer’ experiments of Spemann and Mangold, Ethel Browne demonstrated induction of a secondary axis in hydra by grafting a hypostome. Based on this and subsequent work, in the late sixties, Lewis Wolpert proposed the theory of morphogen gradients and positional information. We have studied secondary axis induction by hypostome and foot tissue using t...