Causal organism : Pyricularia oryzae
It is a most severe disease of rice which is called as Rich men’s disease.
It is also called as Rotten neck or Rice fever disease.
It causes yield loss upto 70 to 80%.
This disease can infect the paddy at all growth stages like
Leaf blast- Entire leaf will have a blast appearance and lodging of crop after emergence of ear
Nodal blast- Nodes becom black and break up
Neck blast- Neck region of panicle develops a black colour and shrivels completely
Grain formation will be inhibited.
Panicle breaks at the neck and droops down.
Formation of Brown spindle eye/boat shaped lesions with grey centre on leaf and leaf sheath(0.5 to 1.5cm length and 0.3 to 0.5cm width).
In severe cases they enlarges and form patches on leaves.
Use thiaphenoate methyl
Seed treatment with Carbendazim @ 2g/kg
Causal organism : Rizactonia solani
It is a condition where seedlings which were healthy will fall over.
It may appear in any stage of the seedling but maximum damge is observed in 5-6 weeks after sowing.
There are two phases
Pre emergence damping off
Seeds which are infected will die before emergence from the soil which results in poor crop stand.
Seedlings will also die before emergence from the soil due to rotting of seeds.
Seedling germinate poorly, wilt and break off and finally die after emergence.
Post emergence damping off
It is the most destructive phase of this.
Here the stems of the seedlings become soft and thin, almost string like where infected.
And finally the seedlings collapse(fall down).
Drench with Redomil gold or metalaxyl
BROWN PLANT HOPPER
Caused by : Nilaparvata lugens
Are white, laid in mass on the midribs and leaf blades and are cylindrical and curved.
BPH adult is brownish black with yellowish brown body.
It has a distinct white band on its mesentrum and dark brown outer sides.
Symptoms of damage
Nymphs and adults can be found at the base of the plant above the water level
Affected plant dries up and gives brown coloured scorched appearance called “hopper burn”.
Circular patches can be found on matured plant.
It is a vector of grassy stunt disease.
Use imidachloprid @ 100-125ml/ha
Early Shoot Borer
Caused by : Scirpophaga incertulas
Are creamy white in colour, flat, oval and scale like and laid in groups.
Eggs are covered with buff coloured hairs
Are pale yellow in colour with dark brown head.
Are white silken cocoon and are found inside the stem
Female moths are bright yellowish and have brown fore wings with a black spot having yellow hairs.
Male moth are smaller with pale yellow forewings without black spot.
We can observe brown coloured egg mass near leaf tip.
Caterpillar bore into central shoot of paddy seedling and tillers, causes drying of the central shoot known as “dead heart”.
Whole panicle will dry and forms “white ear”.
Plants can be easily pulled out by hand.
Use Cartap hydrochloride
By using coragen we can control this shoot borer