Tungro is one of the critical diseases in rice which is very destructive and widespread. In Indonesia, initially, this disease was limited to South Sulawesi. Still, since the early 1980s, it has spread to Bali, East Java, and now it has spread to almost all parts of Indonesia. When the plant is infected, tungro can cause 5-70% yield loss. The earlier the plant is infected with tungro, the greater the yield loss it causes.
The prominent symptoms of tungro attack are leaf discoloration and stunted growth of plants. This characteristic symptom is determined by the level of varietal resistance, environmental conditions, and the growing phase at which the plant was infected. The leaf color of diseased plants varies from slightly yellow to orange. The level of stunting of plants also varies from slightly stunted to very stunted.
Tungro disease is transmitted by green leafhoppers and can be controlled through the alternation of resistant varieties with different parents, the timing of planting, sanitation by eliminating diseased plant sources, and suppression of green leafhopper populations with insecticides. Several tungro-resistant varieties include Tukad Petanu, Tukad Unda, Tukad Balian, Kalimas, and Bondoyudo. Some ways that can also be done are:
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.