Models are useful tools for understanding and improving biological control of arthropod pests by means of natural enemies. Thus, models can be applied to simulate various scenarios in order to identify optimal control strategies. Although simulations can never replace real experiments, they can often serve as guidelines for choosing relevant field experiments and thereby save a lot of laborious and costly field work. Whereas the processes underlying population dynamics (e.g. dispersal, functional response, mutual interference) can be studied under laboratory conditions, large-scaled experiments in the field or in greenhouses are unsuited for this purpose. Instead such experiments may provide information about the patterns (e.g. spatial distributions of prey and predators) generated by the underlying processes. A major purpose of modeling is to link the patterns to the processes that generate these patterns. Petri-dish and single plant experiments have clearly demonstrated the capacity of predacious mite Phytoseiulus persimilis to feed effectively on the two-spotted spider mite Tetranychus urticae. This quickly leads to reductions in the abundance of prey, followed by a decline in predator abundance and eventual extinction. However, when larger systems, consisting of many hundred plants, are infested with the two mite species, extinction of one or both species seems less likely at the system level, although it may still occur at the individual plant level. The qualitative difference between small and large systems with respect to persistence and extinction risks is attributed to the fact that mites move among plants, but to prove that dispersal per se plays a role for the overall dynamics is hard to demonstrate experimentally. To circumvent this problem, I developed a stochastic simulation model of a greenhouse system that explicitly incorporates within and between plant dynamics. The model is used for analyzing a series of experiments with biological control of spider mites in multi-plant systems. In these experiments, the number of plants as well as their connectivity and the numbers of introduced mites were varied in order to examine whether these factors affect e.g. the predator-prey ratio or the time to extinction of one or both species. In my presentation I will also demonstrate an interactive version of the model (called DynaMite). It allows the user to interfere in the system during a simulation so as to mimic the options a grower has in order to prevent losses and to maximize his profit. Such options include spraying with acaricides, releasing predators, and replanting in substitute of damaged plants. By choosing different control strategies, the user may gradually improve his skills according to the principle of learning by experience. The model can be freely downloaded from http://www1.bio.ku.dk/ansatte/beskrivelse/?id=43077

국내에서 많이 재배되는 버섯 중의 하나인 느타리 P. ostreatus는 먹물버섯이나 치마버섯과는 달리 실험실 수 준에서의 자실체 발생이 힘든 것으로 알려져 있다. 본 연구 에서는 실험실에서 느타리버섯을 샤레를 이용하여 전 발 생과정을 유도하기 위한 방법을 검토하였다. 샤레상의 배 양조건은 프라스틱 샤레 (60×15 mm)의 감자배지에서 균사를 접종한 후 빛이 없는 상태에서 배양한 뒤에, 균사의 환기상태, 균사표면의 상처, 빛 그리고 저온충격 등의 여러 환경요인들이 원기 및 자실체 형성에 미치는 영향을 검토 하였다. 느타리의 최초 자실체 형성은 접종 이후 3주 내에 얻을 수도 있었으며, 균사접종 이후 10주 동안에 자실체의 형성은 균주에 따라서 76%에서 97%의 높은 빈도로 유도 될 수 있었다. 위와 같이 샤레상에서 자실체를 형성 할 수 있었으며, 정상적인 자실체의 성장을 위해서 빛은 필수적 이며, 환기도 필요하였다. 또한 균사의 상처 처리가 원기, 자실체 및 포자의 형성에 미치는 영향이 균주에 따라서 크 게 차이가 났으며, 같은 균주라 하더라도 발생단계별 그 반 응의 차이도 크다는 사실을 확인하였다. 이들 자실체에서 수집된 담자포자는 발아가 가능하였다. 샤레상의 완전한 자실체 형성 방법은 느타리버섯의 생육주기를 단축시킬 수 있을 뿐만 아니라, 다양한 재배조건의 시료 획득과 한 개의 배양 용기 내에서 버섯 발생의 전 단계를 관찰하고 분 석하는데 유용할 수 있다.