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Crop Protection

Crop Protection
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.
3
Jul

Symptoms of damage of Root-knot nematodes

 

1. Root-knot nematode affected plants show depletion in vigor, stunted growth, chlorotic and curled leaves in nurseries and main field. 2. The nematode infection is characterized by the formation of small galls near the tips of the roots . 3. Excessive branching of affected roots occurs. The crop damage depends on the density of egg masses/second stage juveniles in the soil.

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 White-tip nematode

1. Rice, strawberry and tuberose are the main hosts of the white-tip nematode.

2. The host range encompasses more than 35 genera of higher plants (Fortuner and Williams, 1975).

3. The wild rice species viz., Oryza breviligulata A. Chev et Roehr, O. glaberrima common weeds like Cyperus iria L., Setaria viridis (L.) Beauv., Panicum sanguinale.

5. Food crops such as maize, bajra and Italian millets (Dave, 1982), Dioscoria trifida L., and common Ipomoea batatas (L.) Poir.

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 White-tip nematode

1. White-tip nematode, A. besseyi is widely prevalent and now occurs in most of the rice growing areas of the world (Ou, 1985) which includes Australia, Ceylon, Comoro Islands, Cuba, El Salvador, Hungary, India, Indonesia, Italy, Japan, Madagascar, Mexico, Pakistan, Philippines, Taiwan, Thailand, USA, former USSR and in most countries of central and West Africa (Franklin and Siddiqi, 1972).

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 Root-knot nematodes

1. Carbofuran, Phorate, Isazophos, Cartap, Carbosulfan or Quinalphos when given as soil application @ 1 kg a.i. /ha significantly reduces the root galling by M. graminicola.

2. Application of 2 and 3 kg a.i. /ha for early and late applications in best results for the control of M. incognita. fenamiphos (@ 6 kg a.i/ha) to reduce root-knot index of M. salasi in rice.

3.Oxamyl @ 500 to 1000 ppm when applied as foliar sprays were effective in reducing M. graminicola followed by soil application of Phorate and Carbofuran @ 1 kg a.i./ha .

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 control of Root-knot nematodes

1. Soil amendments with decaffeinated tea waste or water hyacinth compost (300 or 600g/4.5 kg soil) reduced root-knot nematode infestation and increased plant growth.

2. Rice-mustard-rice, followed by rice-maize-rice and rice-fallow-rice crop sequence was effective in reducing nematode development.

3. Crop rotation with non-host crops viz., sweet potato, cowpea, sesam, castor, sunflower, soybean, turnip and cauliflower inhibit nematode development.

4. In situ green manuring with marigold suppresses root galling and increases rice grain yield by 46% .

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

Biological control of Root-knot nematodes

1. Maximum mortality (>96%) of M. graminicola juveniles occurred when exposed to culture filtrates of Trichoderma harzianum Rifai .

2. Application of Pseudomonas flourescens @ 20 g/m2 was found to be effective in reducing the nematode numbers and increasing the grain yields (ACRIPN, 2003).

3. In in vivo screening tests, Bacillus megaterium significantly reduced nematode galling and J2 penetration compared with uninoculated controls.

4. In addition, in in-vitro tests using culture filtrates of B. megaterium significantly delayed hatching nematode egg and reduced J2 mobility.

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 Root-knot nematodes

1. Rice varieties like Loknath 505 and M-36 M. graminicola at Allahabad (Hassan et al., 2004).

2. Senthilkumar et al. (2007) reported varieties TKM 3, TKM 7, TKM 8, TKM 9, MDU 1, MDU 2, TKM 11 and PY 1 were resistant to this 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

Yield losses by Root-knot nematodes

1. Infestation of M. graminicola causes 16-32% loss in grain yield in upland rice due to incomplete filling of kernels.
2. The threshold level to cause 10% loss is 120, 250 and 600 eggs/ plant at 10, 30 and 60 days age of plants in direct seeded rice.

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 Root-knot nematodes

M. graminicola hatches eggs in water at 25-30oC in water. At 15 and 35oC hatching was reduced and at 20oC it was slightly less than that at 25oC.

2. Larval populations of M. graminicola in soil were high during December to February when soil temperatures was 20.9oC or less.

3. Larval invasion was maximum in soils with 32% moisture content; development and egg mass production were higher at 20 to 30% soil moisture.

4. Maximum larval invasion may occur at pH 3.5 but pH usually has not affect invasion, growth or development of the nematode to any significant extent.

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 Root-knot nematodes with other organisms and disease complexes

1. M. graminicola infestation causes reduction in phenols in the shoots and roots greater susceptibility of nematode infected plants to rice blast pathogen, Pyricularia oryzae (Israel et al., 1963) and root fungus, (Fusarium moniliformae).

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 Root-knot nematodes

1. The root-knot nematode, M. graminicola is an obligate parasite and a major pest of rice. Infective second stage juveniles of M. graminicola select a point for entry into the root, usually the meristematic zone.

2.The juveniles cause disruption, hypertrophy and hyperplasia of cortical cells by intracellular migration and releasing oesophageal gland secretions.

3.The nematode incites development of 5-8 giant or transfer cells in phloem. Around the giant cells abnormal xylem proliferation occurs that causes swelling in stelar tissue.

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 Root-knot nematodes

1. M. graminicola has a wide host range with rice being a main economically important host.

2. It was initially found on barnyard grass, Echinochloa colonum (Golden and Birchfield, 1965). and attacking several grasses, bush bean, oats, Ranunculus pusillus, Cyperus compressus L. , Panicum miliaceum L., Pennisetum typhoides Stapf and C.E. Hubb and Glycine max (L.) Merr ,

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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