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Yellow Rust of Wheat::Identification and Control

August 28, 2011 Leave a comment

The outburst of yellow rust in Distts  of Kathua, Samba and Jammu on variety PBW343 inthe preceding season (2008-09) was serious. This disease survives on volunteer Wheat plants in the hills during the off season. The rust produce yellow pustules in stripes on the leave when the season advances these stripes become black. The rust become severe by the end of February or Ist week of March, the affected leaves dry up, the grain shrivel and the yield is very low.

Favourable conditions:-

 

Cloudy weather, high humidity during Feb. and  March.
Extent of damage:-         Extent of damage range from 20-40%
Recommendations v  Use resistant varieties and adopt timely sowing

v  Rust resistant varieties like DBW 17 and PBW 550 are recommended for Jammu Samba & Kathua region of J&K state.

v  The Sowing of Wheat should be done after treating the seed with bioagent Trichoderma  viride @ 4.0 g/kg seed + fungicide  Tebuconazole 2DS (Rexil) @ 0.1 gm/Kg of wheat seed or Carboxin 75 WP (Vitavax 75 WP) @ 1.25 g/Kg seed.

v  In case of appearance of yellow rust on the crop, spray of Propiconazole 25 EC (Tilt 25 EC) @ 0.1% is recommended to check its further spread. This treatment also provide protection against powdery mildew  and Karnal bunt disease , besides rust.

v   Spray the crop with bayleton 200 @ 0.1% mancozeb @ 0.25% or triadimefon @ 0.01%. Ist spray is to be given at the initiation of disease and repeat spraying after 10-14 days interval.

v  One Spray of propiconazole 25EC @ 0.1 per cent be given on appearance of the disease. This spray should be given on seeing the initiation of the disease in the field or at the appropriate time somewhere in early February

 

 

Paddy Blast in North India-Neck Blast, Leaf Blast

August 10, 2011 Leave a comment

Rice blast:

Causal Agent: Pyricularia grisea, Magnaporthe grisea

Host plants::Specific to rice but also infects some rice field weeds

Affected plant stages::All growth stages but the severe damage occurs during the seedling stage

Affected plant parts::All above ground parts

Control:: Trycyclazole @ 120gm/Acre, pro-phylactic spray gives good benefits.

Brands:: Beam (Dow AgroSciences), Baan, and others

Susceptible Varieties:: Basmati 1121. CSR 30 etc

Sheathe Blight of Paddy

August 10, 2011 Leave a comment

Sheath blight of Paddy:

causative Agent:  Rhizoctonia solani

Occurence:

  • Sheath blight is a fungal disease, more common in rainy season than in dry season in the topics.
  • This disease is problematic in areas where irrigation facilities are abundant.
  • Due to blighting of the leaf sheaths, it is commonly called as sheath blight.
Alternate hosts: Among the plants recorded as hosts are, sugarcane, bean, soybean, tomato, egg plant, tobacco, water hyacinth , hyacinth bean and green gram

Disease Symptoms:

  • Appearance of one or more relatively large, oblong or irregularly elongated lesions on the leaf sheath; in advanced stages center of the lesion becomes bleached with an irregular purple brown border.
  •  Initially these lesions are white in colour later it turns to dark brown.
  • At severe condition drying of leaves.

Chemical control

  • In these days, Validamycin, Hexaconazole, Hexa+ captan, Propiconazole are good restrictive technicals against Sheathe Blight of Paddy. Follow Doses and recommendations as per crop scientist.
  • Seed treatment with carendizm 2.0g/kg of seeds.
  • Spraying fungicides of 2.5g carbendazim 50WP (540g/acre) or 2.5 gm 0f mancozeb 75WP OR 2ml hexaconozole in 1 liter of water.

Late blight of potato

August 10, 2011 Leave a comment

Late blight of potato:

Causative AgentPhytophthora infestans (Fungus)

Host Crop: Potato and other members of the potato family (the Solanaceae) including the tomato.

Symptoms: The disease is first seen as damp areas on the lower leaves of plants that may fuse to form a large brown area of dead or damaged tissue. The pathogen grows out from the leaves on the lower surfaces of the leaves where it is seen as a white downy mass. The disease is at most aggressive under damp conditions and will rapidly kill all the aerial parts of a plant. A cycle of infection to sporulation can take as little as four days. If there is a dry period, the disease pauses but will resume when the weather turns damp again.Infected potato tubers show surface damage only, but the damage may allow other microorganisms to enter the tuber and destroy it. The rot can be so severe that entire fields may smell of rotting vegetation.

Control: The first stage in control of the disease is prevention by good field husbandry. Disease-free seed potatoes should be used for planting and potato waste should be burned or treated with herbicides as should volunteer plants. Disease-resistant varieties should be used when possible and farmers should keep abreast of news of outbreaks to select varieties and treatment. The pathogen is at its most virulent in areas with cool, damp climates or where the soil has become overwatered or over-irrigated so good management of soil water content becomes important when an outbreak is reported.

The infection can be treated by repeated spraying with fungicides including:

  • Chlorothalonil
  • Copper preparations such as Bordeaux mixture
  • Mancozeb
  • Mancozeb-metalaxyl mixtures
  • Maneb
  • Metalaxyl
  • Ridomyl/TATA Master

Repeated spraying may be necessary and even resistant varieties of plant may need more than one application. Ground spraying is more effective and economical, but aerial spraying may be required for some some cultural practices.The disease can spread widely and rapidly, effective communication and monitoring of outbreaks through local or national authorities is essential for control.