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it is necessary to understand the diversity and population biology of the root-knot nematode
present. We are seeking to characterize root-knot nematode populations associated with
mobydick production in Kenya in order to facilitate the development of effective rotations
and introduction of suitable biological control agents for nematode management.
Biointensive Management of Root-knot Nematode in Coleus (Chinese
Potato)
Sheela, M.S & M.S. Nisha
Kerala Agricultural University, India
Root and tuber crops are among the world’s most important cash crops. The coleus or koorka
(Chinese potato), Solenostemon rotundifolius Poir (Morton) is a short-duration, underexploited
tuber yielding vegetable and is mainly cultivated in the homesteads of South India.
The root-knot nematode, Meloidogyne incognita (Kofoid and White) Chitwood is a serious
pest of coleus, causing damage to tubers both in field and storage. The attack of this
nematode resulted in heavy damage of 92 per cent yield loss (Sosamma 1988). Populations of
the nematode pest can be maintained below threshold levels and over-dependence on
pesticides can be avoided by developing a suitable Integrated Nematode Management (INM)
strategy using a combination of control methods and practices giving emphasis to biocontrol
agents and other nonchemical control measures in the nursery and main field. A detailed
study was undertaken to evolve an integrated management strategy in coleus at the College of
Agriculture Vellayani. 2 X 2 m plots had an initial population of 230 to 250 nematode per
200 g soil sample in randomized block design using physical methods (hot water treatment,
soil solarisation ) biocontrol agents (Paecilomyces lilacinus and Bacillus macerans) and
organic amendment (neem cake) in the nursery and main field. Among the nursery
treatments studied, soil solarisation and application of either P. lilacinus or B. macerans were
found effective and selected for further studies in Integrated Nematode Management (INM).
Among the main field treatments, application of P. lilacinus (15g/m 2 ) in combination with
either neem cake (100g/m 2 ) or B.macerans (15g/m 2 ) significantly reduced M. incognita
population and improved the biometric characters, yield and quality parameters of S.
rotundifolius. In integrated management, the selected treatments in the nursery and main field
were evaluated using the resistant variety Sree Dhara. Based on the overall performance in
reduction of nematode population and the improvement of biometric characters and yield of
coleus tubers, integration of soil solarisation in nursery for 15 days with 150 gauge LDPE
film and main field application of P. lilacinus (15 g /m 2 ) in combination with either neem
cake (100 g/m 2 ) or B. macerans (15 g/m 2 ) were recommended as the best treatments in
integrated nematode management strategy for S. rotundifolius. This strategy protected the
crop against M. incognita and improved per ha yield to tune of 64.33 to 66.18 per cent. In
addition, by reducing the nematode population in root (97.89 to 99.73 per cent), the quality
parameters of tubers such as starch, sugar and crude fibre content were also maintained
5 th International Congress of Nematology, 2008 46