Continuous cultivation of mulberry in the same field may favour the survival and multiplication of nematodes causing an infestation called nematodiasis.
The infestation occurs throughout the year and is more prevalent in sandy soils under irrigated conditions causing crop loss up to 15 per cent.
Severely affected mulberry plants are stunted in growth with marginal chlorosis and necrosis of leaves.Symptoms
Underground symptoms are the formation of knots/galls on the roots. Nematode infection hampers the uptake and translocation of water and minerals from the soil.
The infestation spreads primarily through contaminated soil, farm implements and run-off irrigation. Infected saplings, cultivation of other susceptible crops along with mulberry and growth of some susceptible weeds in and around the mulberry gardens act as secondary sources of infection
The nematodeinfestation can be reduced by deep digging /ploughing to a depth of 30-40 cm during summer.
Always use nematode-free saplings for new plantation. Disinfect the farm implements either with 5 per cent formalin solution or dip in boiling water for 5-10 minutes before use.
Plant marigold as intercrop in between mulberry rows. Apply neem oil cake at the rate of 2 mt/ha/yr in four split doses.
Apply furadan (Carbofuran 3 G) at 40 kg/ha/yr in four split doses within 40-45 days. Fumigate the soil with Durofume (Ethylene dibromide + methyl bromide, 1:1) at 9 ml/m.Bionema
Mix one kg of bionema with 24 kg neem oil cake and 200 kg FYM (sufficient for 1,000 plants) and store the mixture under the shade for about one week by adding 30-32 litres of water.
Apply the mixture at 200 g/plant around the exposed roots (three times/year at an interval of four months) Bionema has no residual toxicity on silkworms.
(Dr. N. B. Chowdary, Scientist, Research Extension Central Silk Board, Giddalur -523 357, Prakasam District, A.P. email: email@example.com, Mobile: 09449994014 & Dr. V. Sivaprasad, Director, Central Sericultural Research and Training Institute, Mysore- 570 008, Karnataka).