Browsing by Author "Job Sathyakumar Charles"

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Bio-ecology of the cyst nematode infecting banana
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1989) Job Sathyakumar Charles; Venkitesan, T S
Pathogenicity of the cyst nematode on banana cv. Nendran carried out revealed that the nematode can affect crop growth and yield at lowest initial inoculum of 100 cyst3 per plant. However, the threshold level of initial inoculum of 800 to 1,000 cysts per plant the growth, yield and quality of fruits were considerably reduced. An initial inoculum of 100 to 1,000 viable cysts per plant at planting time could reduce bunch weight by 20.5?£ to 56.6?4. The nematode Infection was observed to affect quality of fruits by increasing acidity and reducing total sugars. This nematode attacks the minute tertiary feeder roots and not observed to attack the fleshy roots and rhizome portions. The attacked feeder roots turn black in colour and detach easily. The final nematode population revealed that there was significant build up in the density of population. The increase ranged from 15*59 to 35.18 per gram root and from 1,168 to 3,188 in 100 gram soil. A significant negative correlation was found to exist with plant growth parameters, bunch characteristics and root weight with the initial inoculum levels of cyst nematode population.
Occurrence of Cosmopolites sordidus (Germar) as an internal borer in banana peduncles
(Kerala Agricultural University, 1986) Job Sathyakumar Charles; Abraham, C C; Joy, P J; Varkey, P A
Screening medicinal plants for antihelminthic properties against different life stages of banana burrowing nematode radopholus similis [Cobb,1893] thorne 1949
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1996) Sreeja, P; Job Sathyakumar Charles
Experiments were conducted at the department of Entomology, College of Horticulture, Vellanikkara to screen medicinal plants for antihelminthic properties against the infective stages of banana burrowing nematode R. similis. The effect of aqueous extract of different parts of 20 medicinal plants were treated at four dilutions and three exposure times. Nematicidal and nematostatic properties of these extracts were studied using the nematode culture developed on carrot callus. The study resulted in the following findings. 1. Extracts of A. indica and G. pentaphylla were highly nematicidal to infective stages of the nematode at all the tested doses. K. pinnata was significantly effective at all the tested doses except 1:40. P. longum resulted in significant mortality at all the tested doses against larval stages whereas only 1:5, 1:10 and 1:20 dilutions were effective against adult stages. Besides nematicidal effect 1:20 and 1:40 dilutions of G. pentaphylla and K. pinnata exhibited nematostatic effects. 2. Leaf extract of M. oleifera and M. piperita at 1:5 and 1:10 dilutions showed significant nematostatic effects against both larvae and adults. P. betle extract was equally effective at the three dilutions. 3. Leaf extracts of C. angustifolia, A. squamosa and L. inermis were not effective at all tested doses. 4. Fruit extract of M. azedarach was nematicidal at all the tested dilutions of 1:5, 1:10, 1:20 and 1:40. But extract of C. papaya was ineffective. 5. Seed extract of C. viscosa expressed nematostatic property at 1:5 and 1:10 dilutions against adult stages, but it was ineffective against larval stages. Treatment with seed extract of E. scandens was ineffective. 6. Rhizome extract of C. rotundus was equally effective against infective stages in causing mortality at 1:5, 1:10 and 1:20 dilutions. Besides nematicidal effects, the extract exhibited significant nematostatic effect. A. calamus extract was nematostatic at 1:5 and 1:10 dilutions. 7. Root extract of I. tinctoria was nematostatic at 1:5, 1:10 and 1:20 dilutions against both larvae and adults. In addition to immobility, it resulted in the death of adult nematodes at 1:5 and 1:10 dilutions. Extract of S. indicum showed significant nematostatic effect at 1:5, 1:10 and 1:20 dilutions against larval stages. But it was effective only at 1:5 and 1:10 dilutions against adult stages. 8. Plant extract of E. hirta expressed nematicidal property at 1:5, 1:10 and 1:20 dilutions against larval stages, but the same was effective only at the two lower dilutions against adult stages