Plant pathogens have being a great threat to plant growth and seed germination. Resistance of seed pathogens is very crucial for plant species to be able to survive from one generation to another. During imbibitions, there must be a complex mixture of chemical compounds within a plant which contains the secondary metabolites (flavonoids, peptides, terpenoids, amino acids, alkaloids, and some other biological materials). for pathogen control. Whether individually or collectively, these molecules though seed exudates can be a powerful source of biological control.
They impart successful biocontrol activity by direct suppression of phytopathogens and by further protecting the host plant through stimulating systemic resistance (Kavitha et al., 2012). The numbers of Bacillus are varying from 106 in cooler regions to 107 or more per gram in warmer regions. B. subtilis, B. mycoides, B. pumihis, B. megaterium, B. thuringiensis and B. firmus are wide range of Bacillus present in rhizosphere soil which affects plant parasitic nematodes (Lin and Dong, 2008). While the genus Pseudomonas is a group of common, nonpathogenic saprophytes that colonize soil, water and plant surface environments. It is a common gram negative, rod-shaped bacterium.
How do mycorrhizae affect plants? many mycorrhizal spores are usually present in the organic matter that is close to the surface of healthy soil, and they typically multiply where there is moist and aerated conditions .If the hyphae of the spores meet with the roots of plant which then provide the hyphae with chemical cues like organic acid that leads to mycorrhizal growth, the hyphae will break through the cell walls to the cell membrane forming chemical passageways between the soil and the plant. Mycorrhizae then get soil water and nutrients from pockets that are inaccessible. it is important to say that mycorrhizae do not colonize to a specific plant or at specific time ;however, they colonize most of the plants and have multiple host at different times .they can work as an intermediate between roots of different species and help in carrying nutrients to the plants with dire need , also they stabilizes the soil ,increase its aggregates and promote in organic matter decomposition .Thus, ending up in a fungal freeway network where nutrient and water can reach plants easily.
There has been lots of researches and studies done on the mycorrhizal fungi to determine its role in establishing plant communities. Mycorrhizal fungi are known to aid in protecting the seedling of host plant roots against the harmful effects such as pathogens and heavy metals. Fungi are also involved in the mycorrhizal symbiosis, nevertheless it is also affecting the multiplicity of interactions, in which it will influence the composition of fungal assemblages and then the colonization of co-occurring plant. Moreover, it may affects the host species, resource availability as well as the plant life history stage. Recent researches have proved that mycorrhizal fungi causes the positive interactions with the plant communities and may affect the structure of plant communities.
Honey Fungus: You can use resistant varieties, avoid water logging, shading, drought areas, protect roots from damage, avoid planting at an infected site, infected roots and stumps should be removed. Soil sterilisation using approved chemical products will control the disease. 3. Slugs: Rake the garden in spring to remove leaves also move boards and other material you may find slugs hide in, trapping and hand picking helps to get rid of slugs. You can also use copper barriers/strips to trap the slugs in, animals such as beetles, shrews, ducks and starlings feed on them.
Even though infection through wounds is uncommon, for some diseases such as crown and finger stalk rot of banana, it is essential (Wang, 2009). The infection strategies of plant pathogenic fungi involve several stages such as attachment and germination of propagules, differentiation into specialized pre-penetration structures such as appressoria, penetration of host cells, development of infection hyphae and colonization of plant tissues (Morin et al., 1996; Gomes et al., 2012). There are a few factors that encourage growth and infection process of this fungus such as inoculum concentration, wetness duration, temperature, age of plant, resistant plant cultivar, pH, nutrient and
2.3 BACILLUS SPECIES The bacillus genus comprises of gram-positive aerobic or facultative anaerobic endospore-forming rod-shaped bacteria that includes both mesophiles and extremophiles (Priest, 1993). Bacillus species are ubiquitous and environmentally diverse, they include thermophilic, psychrophilic, acidophilic, alkalophilic and halophilic bacteria. The bacteria produce spores under unfavourable environmental conditions. Spores produced are resistant to heat, drying, disinfectants and other destructive agents thus remain viable for long periods (Nicholson, Munakata, Horneck, Melosh, & Setlow, 2000). Spores may be oval or cylindrical in shape and may be located centrally, sub terminally or terminally.
According to Wikinson (2010), abundant of Aspergillus grow as saprophytes on decaying vegetation. Then, it also can be found in mouldy hay and organic compost piles. Other than that, Aspergillus can be found almost everywhere, including soil, plant debris, and wood as well as indoor and outdoor air. There are also some of Aspergillus that can be found in compost, for example, Aspergillus Fumigatus which is a pathogenic that can withstand heat. Today, the usage of Aspergillus become widen as it involved in many industrial processes such as enzyme, food stuff and chemicals.
All pests are capable of indirectly damaging other plants by spreading fungal or viral diseases. Disease is any pathological condition caused by other organisms such as bacteria, fungal or viruses. These affect the growth of the plant and in some cases can kill it. Such fungi could be powdery mildew, rust, damping off, honey fungus and brown rot. Bacterial disease could be bacterial canker and viruses can infect fruit, vegetables, and ornamentals.