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Attack Symptoms In Seaweed

Semangun (1996) describes plant diseases when viewed from the angle of biology is a deviation from normal trait that causes the body can not perform normal physiological activities, while from the economic angle plant diseases is the inability to deliver sufficient results, both quantity and quality. Microorganisms (microbes) are not directly cause a disease, but outside circumstances have weakened the plants in advance, so that the bodies can enter or also by causes that work continuously for a long time.

Disease will only occur if the virulent pathogen, and a suitable environment. The disease will not occur if the virulent pathogen that met the most vulnerable parts of the body, but the environment is not supportive. Environment such as humidity, temperature, sunlight and nutrients affect the process. Diseases of the seaweed caused by secondary attack, which comes from the environment. Disease seaweed can also be initiated from cuts or abrasions found on thallus.

Sores or peeled thallus aut grass can be due to poor handling of thallus, injuries from cutting seedlings / seeds or fragmentation may also come from pests bite marks. Sores or peeling thallus if plastered with less clean water or less optimal, it will cause physiological changes in seaweed which ultimately will facilitate disease seaweed in the waters.

The main diseases that attack seaweed is ice-ice that turns out upon closer examination in, found a bacterial infection in the ice-ice. Ice-ice first known to infect Eucheuma in the Philippines in 1974 (Aji 1992 in Santoso, 2008; Sulistiyo, 1988), is a disease that is common in seaweed during the rainy season (October to April) (Doty, 1975; Doty 1979; Mintardjo, 1990). Ice-ice is a disease with a fairly high rate of infection in Asia producing Eucheuma (Philips, 1990).

This disease is an effect of his growing seaweed (Doty, 1979; Trono, 1990) and nutritional deficiencies (Kaas and Perez, 1990), characterized by the emergence of spots / blotches of red in some thallus which gradually becomes pale yellow and finally berangsur- gradually turn white and eventually be destroyed or loss (Aditya and Ruslan, 2003; Aji and Murdjani, 1986; Imardjono et al., 1989; Trensongrusmee et al., 1986; Runtuboy, 2004).

Ice-ice can cause thallus become brittle and easily broken. Symptoms shown is of slow growth, the change in color to pale and in some branches of thallus becomes white and rot. Stress caused by sudden changes in environmental conditions such as: changes in salinity, water temperature and light intensity, are the main factors that spur the emergence of ice-ice disease.

When kelp experience stress due to low salinity, temperature, water movement and light instensitas, will facilitate pathogen infection (Imardjono et al., 1989; Hurtado and Agbayani, 2000; Mintardjo, 1990; Kaas and Perez, 1990). In times of stress, seaweed (eg Gracilaria, Eucheuma or Kappaphycus) will liberate organic substance that causes thallus slimy and thought to stimulate a lot of bacteria growing in the vicinity (Trono, 1974; Aji and Murdjani, 1986; Kaas and Perez, 1990; Uyenco et al., 1981).

Laminaria are also infected with a disease similar ice-ice due to high hydrogen sulfide (H2S) is produced by bacteria saprofit (Wu et al., 1976 in the Yuan, 1990). Ice-ice disease occurrence is seasonal and contagious.

The disease occurs in areas with high brightness, commonly known as ice-ice with symptom onset spots / blotches on most thallus, but over time will lead to loss of color to be white and easily disconnected. The disease attacks Kappaphycus alvarezii or Eucheuma spp. mainly due to changes in the environment (flow, temperature, brightness, etc.) on farms and run in a long time.