Stem rot is a disease that infects plant parts in the canopy and causes plants to fall quickly. To observe this disease, the plant’s canopy needs to be opened. It is necessary to be careful if there is a fall on the plantation without previously raining or raining with strong winds. The initial symptoms are blackish, irregular in shape on the outer side of the leaf midrib, and gradually enlarge. Finally, the fungus penetrates the rice stalks, which become weak, the tillers die, and the plant collapses.
The most susceptible plant stage is the tillering stage until the mature milk stage. Yield losses due to this disease can reach 80%. Plant fertilization with a dose of 250 kg urea, 100 kg SP36, and 100 kg KCl per ha can suppress disease development. To reduce the spread even further, dry the plants until harvest time. Ways to prevent this disease include:
Source: Putra, R. (2018). Hama dan penyakit tanaman padi dan deskripsi padi sawah. Balai Pengkajian Teknologi Pertanian Kepulauan Riau.
The fungus Helmintosporium oryzae causes brown spot disease in plantations. Brown spots can cause the death of young plants and reduce grain quality. Like Cercospora spot disease, this disease is very damaging to rice cultivation on land with poor drainage systems or land deficient in nutrients, especially potassium. The condition is rare in arable land. The most common symptom of this disease is brown spots, oval to round in shape, about the size of a sesame seed, on the leaf surface, on the midrib, or the grain.
Cercospora spots are caused by the fungus Cercospora oryzae. The disease causes serious damage to crops on less fertile land. The disease produces straight, narrow brown symptoms on the flag leaf blade in the ripening growth stage. Symptoms can also occur on the midrib and husk of the grain. The disease was controlled with complete balanced fertilization, with doses of 250 kg urea, 100 kg SP36, and 100 kg KCl per ha.
Infection occurs in the upper leaf sheath covering the young panicle at the end of the pregnant phase. The initial symptom is the presence of an elongated to irregular round spot with a length of 0.5-1.5cm, gray in the center and brown or gray-brown at the edges. The spots are enlarged, often continuous, and can cover the entire leaf midrib. Severe infection causes the panicles to appear only partially (not growing) and shrivel up.
