Solution to prevention and treatment of dirty grain

Dirty grain is a syndrome caused by many agents on rice grain. Dirty grain may be caused by fungus, bacteria, viruses, and insects when the rice still on the field. This syndrome may also occur after harvest when storing in the silo.

1. Harmness of dirty grain syndrome: 

“Dirty grain” has 2 symptoms: “discoloration” and “flattened” grain. “Discoloration” degrades the quality of the rice grain. “Flattened” grain decreases the yield of the rice field.

Rice Dirty grain with fungus will be the pathogen to spread the disease to the next season’s young seedlings, otherwise, these pathogens will cause white dwarf leaves symptoms or bakanae to the young seedlings.

2. Agents that caused the Dirty grain disease

a) Fungus that caused the Dirty grain:

Have at least 19 types of fungus that causes the Dirty grain (Pyricularia oryzae, Cescospora oryzae, Tilletia barclayana, Phoma sorghina, Trichothecium sp., Pinatubo oryzae, Microdochium oryzae, Fusarium fujikuroi, Curvularia lunata, Trichoconis padwickii, Pinatubo oryzae, Nigrospora sp., Bipolaris oryzae, Acremonium sp., Ustilaginoidea virens, Trichothecium sp., Pythomyces sp., Alternaria sp., Chaetomium globosum.)

b) Bacterias that caused Dirty grain:

Bacterias that caused Dirty grain including Burkholderia glumae, Xanthomonas oryzae pv. oryzae, Pseudomonas fuscovaginae and Acidovorax avenae sub sp. avenae.

c) Steneostarsonemus spinkii (spyder-type) cause Dirty grain:

Steneostarsonemus spinkii is the agent of melasma sheath that also causes Dirty grain.

d) Insects that caused Dirty grain:

Bugs also cause Dirty grain syndrome.

3. Symptoms of the Dirty grain syndrome

The rice grain may be flattened, the husk of the infected grain may have light green color and change to yellow, or have brown smears, dots, from dark brown, purple to black.

Symptoms depends on agents.

a) Fungus-caused Dirty grain:

Fungus makes on the grain the brown, purple to dark brown, dark purple, have or not have white dots in the center. Within the conditions of high humidity, have white dust cover on the discolored smear. The rice grain usually flattened completely.

b) Bacteria – caused Dirty grain:

Yellow flattened caused by bacteria: Rice grain becomes flattened, rice husk doesn’t change color. Rice embryo (inner rice grain) shrinks small with black rotten streak. The disease harm every grain in the same branch of the rice arista caused that branch flattened and have light weight.

Black rotten grain caused by bacteria:  The infected grain has black stains in the rice husk, usually seen on the top of the grain.  Inner rice grain softly rotten may have liquid spray out when squeezing the grain.

c) Steneostarsonemus spinkii (spyder-type) cause Dirty grain:

Steneostarsonemus spinkii deals big damage before the rice blooms, the grain after blooms may be discolored or flattened. Discolored grain usually has light black color on the husk. However, discolored grain may have purple color caused by the secondary fungus.

d) Insect – caused Dirty grain:

Bugs inject and suck the young rice grain may cause Dirty grain. Infected grain has a brown and round stain with a white dot in the center. In some case, may see the injection mark from bugs right in the middle of the discoloration stain.

4. Solution to prevention and treatment

• In the field, infected grains usually have agents stick on, so eliminate infected from the beginning phase will reduce the harm. Use 15% Sodium solution to eliminate the flattened and discolored out of the seed batch.

During cultivation, pesticides on the “scattered bloom” phase and “full bloom” phase are necessary to prevent Dirty grain syndrome.

• Use MAP SUPER 300EC and MAP LOTUS 125WP to prevent and treatment of rice Dirty grain.

MAP SUPER 300EC with 2 wide spectrum anti-fungus has high efficiency with Dirty grain caused by fungus.

Propiconazole … 150 g/l

Difenoconazole … 150 g/l

Combine 02 active ingredients. Systemic action and absorb rapidly

Have good harvest, shiny yellow grain.

Prescription: 0.3 – 0.35 l/ha; concentration: 25ml/25l bottle.

MAP LOTUS 125WP combines 2 anti-bacteria mechanisms: Streptomycin inhibited protein synthesis (not attached acid main) and Oxolinic acid inhibited DNA synthesis (not RNA de-helix) that helps prevent and treatment of Dirty grain caused by bacteria.

Streptomycin sulfate … 25 g/kg

Oxolinic acid … 100 g/kg

Specially control bacteria disease.

Broad – spectrum control, quickly affect.

Prescription: 0.4-0.6kg/ha; Concentration: 25gr/25l bottle

When to use: pesticides on 2 phase: “scattered bloom” and “full bloom” phase to prevent and treatment of the Dirty grain on rice.