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Non Insects

Non Insects
3
Jul

Cultural control of Lesion nematode

1. Fallowing or rotation with Phaseolus radiatus decreased the root-lesion nematode.

2. Neem cake gave greatest reduction in nematode population.

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Chemical control of Lesion nematode

1. Application of Carbofuran or Phorate @ 1 kg a.i./ha to the soil with affected crops reduces the nematode injury and avert losses in grain yield loss up to 48.5%.

3. As the lesion nematode damage appears much late in the season, the chemical treatment may not be effective for the early sown crop.

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Yield losses by Lesion nematode

1. In India yield losses due to infection by P. zeae and P. indicus are 13-29% and 33% respectively.
2. The yield loss is mainly due to ill filling of kernels, and to reduction in the weight.
3. Nematode infection also reduces the protein content of the grain.

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Life cycle of Lesion nematode

1. P. indicus needs 33-34 days to complete its lifecycle and several overlapping generations occur in a
single crop.

2. The nematode invades the plant roots at a selected point singly or in groups. After gaining entry the nematode feeds on the cortical cells and forms galleries.

3. Infected roots develop water soaked lesions and at times swellings also observed.

4. The necrotic patches coalesce and develop brown to black lesions.

5.The optimum temperature for P. indicus to reproduce is 23-30°C and peaks of population are always preceded by rainfall.

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Symptoms of damage of Lesion nematode

1. The nematode infected plants become stunted and even smothered, resulting in patchy growth in fields. Chlorosis of leaves and reduction in number of ear heads and grains are also seen.

2. The nematode infected roots appear swollen with water soaked lesions leading to development of black necrotic lesions on the root surface.

3. In advanced stage of damage, the lesions coalesce with the result the whole root turns black in colour.

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Host range of Lesion nematode

1. Rice is a main host of P. Indicus nematode.

2. Cyperus iria and Eleusine indica (L.) Gaertn also serve as main hosts for P. indicus and P. zeae the nematodes.

3. Weed species viz., Cynodon dactylon, Amaranthus spinosus L., Dactylotenium aegypticum (Desf.) Beauv., Digitaria sanguinalis Scop. and Echinochloa sp. Also host to nematode.

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Distribution of Lesion nematode

1. Lesion nematodes are widely distributed in the world and mainly inflict damage to direct seeded rain fed rice.

2. In India, Pratylenchus spp., particularly P. indicus and P. zeae have been recorded on rice in Andhra Pradesh, Assam, Gujarat, Kerala, Orissa, Madhya Pradesh, Rajasthan, Uttar Pradesh and West Bengal.

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Lesion nematode (Pratylenchus spp.)

 

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Chemical control of White-tip nematode

• Seed treatment with Thiobendazole, Benomyl or Fenitrothion reduced nematode population to a very low level.
• Pre-soaking of seeds with Oxamyl or hot water treatment reduced the infestation like and increased yields.
• In USSR, pre-sowing treatment of rice with the organic mercury compounds Granozan and Hydrogen peroxide reduced A. besseyi infestation of rice panicles, improved the density of the rice stands by 10-11% and increased the yields by 13-36%.

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Cultural methods of White-tip nematode

1. The damage due to nematode is less when direct seeding was done in the field cultivation when can pared to the field flooded after seeding (Silva and da Silva, 1992).

2. Damage due to this nematode can be minimized reducing the nematode activated nematode by thoroughly washing the pre-soaked rice seed with excess amount of water before sowing in the nursery.

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Physical control of White-tip nematode

1. Storage of A. besseyi infested seeds in regulated gas medium (97.5% nitrogen and 2.5% oxygen) for 10 days at 25oC controls nematode effictively.

2. Treatments with either Ethoprophos 20EC at 0.5% or hot water at 53-54oC for 15 min reduced the infestation of nematodes in seed to almost free level (Tacconi et al., 1999).

3. In addition to hot water treatment, a combination of seed treatment and spraying with Benomyl protects rice plants from infestation A. besseyi .

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Host plant resistance of White-tip nematode

1. use of nematode free or resistant planting materials the most effective control method for A. besseyi (Silva and da Silva, 1992).

2. Rice genotypes like Bluebelle, BR-IRGA 409 and IRGA 172 F4 SS39 did not show any symptoms of white tip when inoculated with A. besseyi in Brazil (Oliveira and Oliveira, 1989).

3. In USSR, utilizing the progenitors of almost all the resistant varieties bred there in the last 40 years i.e. Fortuna, Nira, Rexoro and Bluebonnet, a notable derivative Bonnet 73 with multiple resistances to A. besseyi and various other diseases was developed.

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Yield losses by White-tip nematode

1. The yield loss due to chaffy ear heads developed by nematode infestation was 20% (Muthukrishnan et al., 1974).

2. The ear head damage with partially filled grains due to nematode damage ranged from 21-46% (Nandakumar et al., 1975).

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Effect of environmental factors on White-tip nematode

1. The nematodes are active at a temperatures ranging from 13-42°C with ideal relative humidity above 70%.
2. At 60°C the survival of A. besseyi was 40% therefore rice seed germination is not affected.

3. The nematode can remain alive for 1 year in rice seeds between glumes and grain, and 53 days in water at 10°C.

4.The minimum temperature favourable for nematode activity is 4°C and the thermal death point is 49°C for 10 min.

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Interaction of White-tip nematode with other organisms and disease complexes

1.Pathogenic fungi Acrocylindricum oryzae and Dorticium sasaki invade the interveinal areas of nematode affected leaf (Rao and Rao, 1979).

2. Delay in panicle emergence due to nematode feeding on the inner layers of boot and increased humidity facilitated infection by opportunistic fungi like Fusarium spp easily.

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Host-parasite relationship of White-tip nematode

1. A. besseyi feeds endoparasitically in the coleoptile for 7-10 days in the initial stages of development of rice plants and ectoparasitically within the innermost leaf sheath during later plant growth stages.

2. At late tillering stage, nematode numbers may increase rapidly, and reach a peak during the reproductive stage of the plant.

3.Damage to the outer wall of the ovary causes partial filling of kernels and damage to the lodicules prevents closure of flower after anthesis, exposing the embryo to promotes infestation by Alternaria padwikii and sterility (Rao and Rao, 1979).

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Life cycle of White-tip nematode

1. A. besseyi is bisexual and an ectoparasitic nematode and needs 6-7 days to complete its life cycle.
Duration of life cycle may vary according to the ecological factors i.e. 3 days at 31.8oC to 29 days at 14.7oC (tikninova 1966)

2.The duration of life cycle from egg to egg is about 6 to 7 days. In nature, the length of life cycle depends on the ecological factors and it may take 3 days (at 31.8oC) to 29 days (at 14.7oC) for completion of life cycle (Tikhinova, 1966).

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

Symptoms of damage of White-tip nematode

 

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
3
Jul

White-tip nematode (Aphelenchoides besseyi Christie, 1942)

 

File Courtesy: 
http://www.eppo.org/QUARANTINE/nematodes/Aphelenchoides_besseyi/APLOBE_ds.pdf
3
Jul

Life cycle of Root-knot nematodes

 

File Courtesy: 
Status of Rice Nematode Research in India, Prasad, J. S., Somasekhar, N. and Varaprasad, K.S. (2011). Approach Papers written for Rice Knowledge Management Portal.
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