Radopholus

learn about life stages of migratory endo parasites especially burrowing nematode

1. Study of Life Stages of Migratory Endoparasites Burrowing Nematode - Radopholus similis Prepared by R MOHANAPRIYA Assisstant Professor (Plant Pathology) JSA College of Agriculture and Technology, Ma. Podaiyur, Cuddalore district, Tamilnadu

2. Systematic position Phylum : Nematoda Class : Secernentea Order : Tylenchida Suborder : Tylenchina Super family : Tylenchoidea Family : Pratylenchidae Sub-family : Pratylenchinae Genus : Radopholus Species : similis Major hosts : Black pepper (pepper yellows) & Banana ( Fusarial wilt) Type of parasitism : Migratory Endoparasite (Gr. Radix-root, phelien -loving) denotes endoparasitic mode of life, Common name ‘burrowing nematode’ is coined beacause it causes extensive cavity formation in roots due to migratory behaviour. 1 st observed by Cobb in 1890-91 in banana disease in Fiji

3. Female Vermiform 0.5-0.8 mm long Lip region low, set off , spear strong with well developed basal knobs Oesophageal glands overlapping intestine dorsally Ovary – didelphic Vulva median Tail conoid to blunt with rounded terminus Female anterior region

4. Male Spear very slender with tiny knobs Oesopagus reduced Bursa extending upto 2/3 of the tail Male anterior region

5. Economically important species R. similis (now known as R. citrophilus ) is considered as economically very important species in tropical and subtropical areas of the throughout the world In India introduced into Kerala by banana suckers from other countries It occurs in TN, AP, MP, Goa, Maharastra , Gujarat, Karnataka Serious problem in B anana, P epper, Coffee, Tea, Cocoa, Coconut, Arecanut , Sugarcane, Turmeric, G inger

6. Life cycle Females and all juvenile stages are infective. Males are non-parasitic and morphologically degenerate (without stylet ). Penetration occurs mostly near the root tip. The nematode penetrates within 24 hours and the cells around the site of penetration become brown. After entering the roots, the nematodes occupy intercellular position in the cortical parenchyma where they feed on the cytoplasm of nearby cells causing cavities which coalesce to form tunnels. Nematodes do not enter the stellar portions of the root.

7. The nematode completes its life cycle within 24-30 days at a temperature range of 21-32°C. Females lay eggs within infested tissues with an average of 4-5 eggs for two weeks. Eggs hatch after 8-10 days and the juvenile stages are completed in 10-13 days. A low soil temperature, adequate soil moisture and availability of fresh tender roots help in the build up of population.

8. Spread of necrotic lesions from roots to rhizome in banana infected with Radopholus similis

9. Symptoms Fusarial wilt of Banana F. Oxysporum f.sp . cubense Stunting of plants Reduction in size and number of leaves and in bunch weight. Appearance of dark red lesion on roots. Toppling of plants in windstorms or heavy rains Management Fallowing for a period of six months or longer. Crop rotation with non-host crops. Use of disease free planting material. Storage of large corms in the sun for two weeks prior to planting. Use of cover crop Calapogonium . Removal of infested portions of corm before planting. Hotwater treatment at 55 o C for 15-25min. Paring and Pralinage Carbofuran 3 g @40g/ plant at 90 days after planting. Application of neem cake

10. Black pepper Yellow disease Yellowing of leaves Complete defoliation Reduces the berry production Vines become unproductive Roots are devoid of laterals, extensive necrosis on the main roots Management Apply Fensulfothion @ 4-8kg a.i ./ha at nursery stage is effective to control nematode infection