جستجوی مقالات مرتبط با کلیدواژه « anthracnose » در نشریات گروه « گیاهپزشکی »

Plant disease can cause quality and quantity reduction of agriculture crops. In some countries farmers spend considerable time to consult with plant pathologists, whereas time is an important factor to control disease, so it seems to offer a fast, cheap and accurate method to detect plant diseases. Since the fungal disease named ‘Powdery Mildew’ and ‘Anthracnose’ cause the greatest amount of damage in cucumber produced in greenhouses, thus in this research the mentioned two fungal disease detection and classification were studied using image processing and neural networks technique. Image processing steps includes four main steps: 1) Image acquisition 2) preprocessing 3) extraction of the best color parameters of HSV and L*a*b* color spaces in order to classify and extract defected area of the leaf and 4) extraction of textural properties of defected area of cucumber leaf using co-occurrence matrix. Since, two factors of accuracy and time are important in detection and classification of plant disease, thus artificial neural networks (ANN) with back propagation algorithm (BP) and Levenberg-Marquardt (LM) training function was selected as the best model that was able to successfully detect and classify mentioned plant diseases in 6 seconds with 99.96% accuracy.

Anthracnose disease is one of the most destructive diseases of strawberry which caused by Colletotrichum acutatum, C. gloeosporioides and C. fragariae. C. acutatum and C. gloeosporioides species complexes possess wider host range. According to the latest multi-gene phylogenetic evaluation, different strains of the causal agent of strawberry anthracnose disease which have been collected from different regions of the world, belong to these two species and are divided into several clusters, related to cryptic species. Despite infecting various parts of the plant, C. acutatum is mostly responsible for fruit rot and in comparison with two other species, causes crown rot and is more prevalent and destructive. Dispersal of pathogen inoculums mainly takes place by rain splash and sprinkler irrigation as well as by movement of human beings and animals. Integrated management of this disease is mainly achieved through cultural, chemical, biological and the use of resistant cultivars. Giving the importance of strawberry anthracnose disease in terms of damage rate and its recent incidence in many strawberry growing areas in Iran, different aspects of the disease, including diagnosis of the causal agent, biology and efficient management methods are discussed in the present review.

Walnut tree is one of the most important orchard and jungle trees in Iran. It's world cultivation is growing up due to its plentiful uses. Meanwhile, some pests and diseases are known as the major reasons of restriction in walnut cultivation. Among walnut diseases, anthracnose is the most destructive in Iran. In this study, the main area of walnut cultivation in Zanjan were surveyed, walnut's infected organs (sprouts, leaves and fruits) were sampled and the disease agent was isolated and identified using ordinary plant pathological methods. The results showed that Ophiognomonia leptostyla (Fr.) Sogonov contribute to the walnut anthracnose disease, and it is permanently scattered in all Zanjan walnut orchards. It's damage varies between15% to 67% in different regions. Our study on Telemorph and Anamorph phases of the fungus showed that there are no significant differences between isolates collected from Zanjan and those from other provinces in vicinity. Meantime, the results showed that the majority of the collected isolates were Heterothal. Study on partial resistance of three Iranian local genotypes (Z53, Z63 and 60) and six exotic cultivars (Sere, Lara, Franket, Pedro, RDM and B21) showed that local genotypes were more susceptible to walnut anthracnose in comparison to exotic varieties. Although none of the varieties and genotypes was totally resistant, in comparison to introduced interior superior genotypes, exotic varieties of Persian walnut were by far in better condition against anthracnose.