The weather condition in the Arkansas are favorable for the growth of Rice blast pathogen. Rice blast pathogen spores can easily move across a field and/or from a field to another by wind causing a blast epidemic .
Rice blast pathogens attacks the plants at leaves, nodes, the collar, the neck, and panicles of rice plants. The worst of all is neck blast. Neck blast (neck rot) may cause near 100 percent yield loss unless checked by fungicides but fungicides also do not guarantee neck blast control throughout the season.
Planting a resistant variety of rice is the best control method. However, it does not guarantee lasting control of blast since the pathogen population dynamics could alter.
If we plant the rice earlier it may also not guarantee full control of blast. as if weather is favorable, and field conditions are encouraging for pathogen growth, reproduction, and spread then it may also get a affected.
Conditions that favour the growth of Rice Blast pathogens are:
- Fields with heavy tree lines, especially on the east side – which prolongs night-time dew period – are more likely to develop blast if planted with susceptible varieties.
- Soil types where a deep flood cannot be maintained are more prone for blast disease.
- High nitrogen in fields with blast history makes susceptible varieties prone to the disease.
- Fields with history are likely to get the disease if planted with susceptible varieties.
- Fields in river bottoms with longer dew periods are prone for the disease.
- Fields low in potash and low irrigation capacity favor disease development.
- Low cut fields when leveling get low in fertility, particularly potash.
Weather conditions that favor blast:
- Frequent light rains that allow extended leaf wetness
- Extended cloudy days that allow slower leaf drying Slow winds that transport spores and slow leaf dryness
- Warmer days and cooler nights that allow long dew periods
Preventive Measures that are to be taken to protect crops from Pathogens
- Cultural practices usually influence the development of disease in plants by affecting the environment. Such practices are intended to make the atmospheric, edaphic, or biological surroundings favorable to the crop plant, unfavorable to its parasites. Cultural practices that leads to disease control have little effect on the climate of a region but can exert significant influence on the microclimate of the crop plants in a field. Three stages of parasite’s life cycle namely, Survival between crops, production of inoculum for the primary cycle and inoculation can be control by following preventive measures.
- The pesticidal chemicals that control plant diseases may be used in very different ways, depending on the parasite to be controlled and on the circumstances it requires for parasitic activities. E.g., a water-soluble eradicative spray is applied once to dormant peach trees to rid them of the overwintering spores of the fungus of peach-leaf curl, whereas relatively insoluble protective fungicides are applied repeatedly to the green leaves of potato plants to safeguard them from penetration by the fungus of late blight. Also, systemic fungicidal chemicals may be used therapeutically. The oxathiin derivatives that kill the smut fungi that infect embryos are therapeutic, as is benomyl (which has systemic action against powdery mildews and other leaf infecting fungi). Volatile fungicides are often useful as soil-fumigating chemicals that have eradicative action.
- Get the disease diagnosed correctly. Incorrect diagnosis could be costly.
- Maintain a consistent > 4 inch flood especially at all times until it is time to drain. –
The most common mistake that leads to fungicide failure:
- Waiting too late to apply fungicides
- Using the wrong products.
- Using reduced rates of the fungicides.
Following the above precautions and methods the farmers in Arkansas will definately protect their crops from the attack of rice pathogens.