DEFINITION Biological agents

Biological agents are the Biological Control Agent (Biological Control Agent), any organisms that includes species, subspecies, varieties, all kinds of insects, nematodes, protozoa, fungi (fungi), bacteria, viruses, and other organisms that mikroplasma in all stages of its development can be used for the purposes of controlling pests and plant diseases or pests in the process of production, agricultural processing and various purposes. Biological control agents are called pathogens that can be classified into 2 groups: pathogens of insects and plant pathogens antagonist agents

A.      INSECT PATHOGENS

Bacterium Bacillus thuringiensis (Bacillaceae family) that are generating secondary metabolic antibiotics, toxins and enzymes. Income secondary metabolic processes take place when the vegetative growth period or sporolasi. Bacillus thuringiensis including anaerobic spore-forming group, a species complex consisting of more than 20 serotypes or subspecies. These serotypes produce toxins that are insecticide (Insectiside Protein Cristal) delta-endotoxin them useful in agriculture. Infection process, in general, the food channel is the first organ to bacteria. In the channel, the toxin the bacteria will undergo decomposition (hydrolysis). Toxic fractions will be released from the crystal, so that the poison duct epithelia cells food. Symptoms of attack, in the early stages of bacterial infection, insect feeding activity is decreasing and tend to seek refuge in a hidden place (under the leaves). Furthermore larvae diarrhea, discharge from his mouth, experiencing paralysis (paralysis) on the food channel; resulting in decreased motor activity and ends with death. said fungus that serves as a biological control entomopathogenic Deuteromycetes generally of class, order Moniliaales, such as Beauveria bassiana, Metarrhizium anisopliae, Hirsutella saussurei, nomuraea riley, and Paecilomyces sp. entomopathogenic fungi have a high reproductive capacity, short life cycle, can form spores that survive long in the wild, safe, selective and compatible with a variety of chemical insecticides. However, the success of the use of entomopathogenic fungi as pest control in the field is influenced by lingukungan factors (temperature, humidity, and sunlight), the number of spores that are sprayed on the possibility of spores to the target application and the time is right. The infection process, the inclusion of the fungus on the host insect body through the integument, digestive tract, spiracles and other openings.  Inokulun fungi that attach to the body of the host insect will germinate and grow to form germ tubes, then enter the body through the skin (ingumen). Penetration is done mechanically and chemically by releasing an enzyme or toxin or fungus will further develop in the body and invade host tissues throughout the body, so that dead insects. Symptoms of Attacks, insect pathogenic fungi are attacked by the body will die like a mummy hardened, brittle and fungus to grow over the insect host's body with color white or dark green fungus.

Antagonist agents suppress plant pathogens in plant pathogen populations or activity can be hiperparasitisme, competition for space and nutrients and antibiosis and lysis. Antagonist agents of plant pathogens are microorganisms that intervene in the activities of pathogens cause plant disease. The agent can not pursue a host that has been entered into the plant. Its effectiveness can be seen with the development of the disease. Pseudomonas fluorescens bacteria can produce spores, which are aerobic gram-negative, is found in many areas rizofir and soil, as well as more effective at neutral and alkaline soil. Planting in moist soil can increase the population, root colonization which is a requirement as a biocontrol agent. Process Antagonist, Pseudomonas fluorescens antagonistic mechanism of the type of competition in the form of nutrients in the soil. Can suppress the development of Fusarium sp. through competition for available Fe element. trichoderma fungus Gliocladium sp and sp is the antagonist agents plant has been developed in the manufacture of bio-organic fertilizer. Fungus Trichoderma sp. effective on acid soils. At neutral pH, and inhibited germination of propagules germinate even under alkaline conditions. This fungus is very much like materials containing cellulose, such as the remnants of straw, corn stalks and grasses. Trichoderma sp Fe sensitive to the decrease caused by Pseudomonas fluorescens, so these two antagonistic agents is not compatible when applied together. Process antagonists, Trichoderma sp. active attack Rhizoctonia solani and Pythium sp that produce chitinase and B-1.3-glucanase, with the antagonist parasitism. While Gliocladium sp. which are antagonistic toward some soil borne pathogens such as Fusarium moniliforme and Sclerotium rolfsii, the antagonist in the form of the workings of parasitism, competition and anti BIOSIS.

Role in the Environment

Trichoderma is a fungus that can be isolated inhabitants of the land from the field of plant roots. Trichoderma species as well as decomposing organisms, can also function as an agent of biological and plant growth stimulator. Some species of Trichoderma have been reported as biological agents is T. Harzianum, T. Viridae, and T. Konigii broad spectrum on a variety of agricultural crops. Trichoderma fungi in culture media such as bran applicative can be given to the planting area and apply as biodekomposer, which can decompose organic waste (leaves and twigs crumbling old) into quality compost. Moreover, Trichoderma can also be used as biofungisida, where Trichoderma has the ability to be able to inhibit the growth of several fungi that cause disease in plants, among others Rigidiforus lignosus, Fusarium oxysporum, Rhizoctonia solani, Sclerotium rolfsii, etc..
Currently, one of the microorganism Trichoderma is widely known as a functional biological soil fertilizer. Trichoderma biological fertilizer can be made with a pure culture inoculation on the medium applied, for example bran. While pure cultures can be made through the isolation of plant roots, and may be reproduced and rejuvenated on PDA (Potato Dextrose Agar).
Trichoderma is often a particular problem in the mushroom cultivation industry, where Trichoderma can be parasitic on the mycelium and fruit bodies of other fungi. When other fungal parasite into the host Trichoderma, then develops very quickly on the surface to form green colonies, thus making a bad mushrooms and other fungi remodel. Fungus Trichoderma viride was also used to increase the value of the benefits of rice straw by fermentation, because these fungi have cellulolytic properties and secrete the enzyme cellulase which can remodel the cellulose into glucose selubiosa until it became. The process that occurs when the fermented rice straw using Trichoderma viride is the degradation of the cell wall diselaputi by lignin, cellulose and hemicellulose. As a result of this degradation would then partially degraded lignin. Cellulose and hemicellulose will also break down into glucose.

Ecology
Trichoderma spp. can be found in almost any type of soil and the variety of habitats. This fungus can multiply rapidly in the root zone. In addition, Trichoderma spp. is a parasitic fungus that can invade and take nutrients from other fungi. The role of Trichoderma spp. capable of attacking other fungi and yet well developed in the root zone to make the existence of these fungi can act as biocontrol and improve plant growth. Some Trichoderma species such as T. harzianum, T. viride and T. album, has researched his role as a bio-control. A. Aspergillus nidulans, including the type and be able to rapidly multiply in shaping fungal filaments both in liquid medium and solid media and in various nutrition (Setyowati, et al, 2003). Aspergillus can be found in soil, litter and in the air. Aspergillus can cause infection, allergy or toxicity either in plants, animals and humans (Setyowati, et al, 2003).