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Open Access
Land evaluation and suitability rating of the major soils of Onattukara region
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1998) Premachandran, P N; KAU; Subramonia Iyer, M
The need for a scientific approach in inventorying and utilizing land resources most economically and efficiently is now universally accepted. Agricultural prosperity, to a great extent, depends on judicious use of soils and rational application of soils data. A reconnaissance soil survey of Onattukara region was undertaken to study the extent and distribution of the different soils for soil classification, land capability and irrigability classification and for subsequent land evaluation. The study reveals that Onattukara region extends over an area of 40,948 ha. The soil map showing the distribution of the identified twenty soil series has been prepared. The climatological data reveals that the soil moisture regime is , ustic and the soil temperature regime is isohyperthermic. The soils have been classified as per Soil Taxonomy (U.S. Soil Survey Staff, 1975) and Keys to Soil Taxonomy( U.S. Soil Survey Staff, 1994 and 1996). Ten series were classified under Entisols, SIX under Inceptisols, three under Ultisols and one under Alfisols. Based on the inherent soil characteristics and landscape features, the soils have been grouped into three land capability classes, nine capability subclasses and land capability map prepared. The soils were classified into five land irrigability classes, eight land irrigability subclasses and land irrigability map prepared. The soils were evaluated based on principles of land evaluation and rating of productivity parameters. The productivity rating of the soil propertIes agamst the productivity index for nee, coconut, sesamum ,cassava and banana were made and conclusions arrived at. Productivity rating shows that Kottakakam series is best suited for rice, Palamel, best for coconut and banana, Artuva and Mahadevikad, for sesamum and Palamel and Vallikunnam, for cassava. On the basis of the studies carried out, a land use is proposed for the twenty soil series of Onattukara region based on crop suitability ratings and crop suitability map prepared for the five crops taken for study. A proper soil survey interpretation provides information on soil potential, productivity and limitations in their sustained use. Soil survey information forms the major basis for land evaluation. A thorough knowledge of the potentialities and limitations of every piece of land is a prerequisite in its efficient utilization. A systematic survey is essential for the evaluation and classification of the soils based on their inherent soil characteristics, land capability, land irrigability and land suitability. A systematic survey and evaluation of the soils of Onattukara region was taken up to study, interpret, classify and to show their location and extent on base maps. It is hoped that the present study would open up avenues for further investigations on land evaluation, crop suitability and other management aspects for sustained use of soil resource data to the best advantage. This will also form the basis for microlevel planning for integrated and sustainable development of the region under Panchayat raj.
Open Access
Management of foot rot of black pepper (piper nigrum L.) with va mycorrhiza and antagonists
(Department of Plant Pathology, College of Agriculture, Vellayani, 1998) Christin Robert, P; KAU; Sivaprasad, P
Extensive investigation was carried out to develop a native microbial inoculant based technology involving Arbuscular Mycorrhizal Fungi (AMF) and fungal antagonists for the foot rot disease management and growth improvement of black pepper in the nursery and field. Phytophthora capsici Leonian emend A. Alizadeh and P.H. Tsao, the foot rot pathogen isolated from Peringammala, Thiruvananthapuram district was found most virulent isolate. Seven native AMF cultures and fifty fungal antagonists were isolated from Kerala soils. AMF isolates were screened in the green house for plant growth improvement and disease tolerance in comparison with identified species-Glomus fasciculatum, G.clarum and Gigaspora margarita. Of the ten AMF tested isolates Is - 6, Pi - 11, Pi - 9, G. fasciculatum and Gigaspora margarita were very effective in stimulating growth and nutrient (P, K, Ca, Mg, Cu, Fe, Mn and Zn) uptake of black pepper. Regarding the ability of AMF in reducing the foot rot incidence, Glomus fasciculatum recorded the lowest plant mortality and root rot index (53.35% and 62.50%) followed by Is - 6 (60.00% and 64.77%) and Pi - 11 (60.64% and 68.18%) as against 100 per cent mortality and 98.60 per cent root rot index noticed in control. The above five cultures were subjected for further studies. Characterisation of AMF associated with different genotypes of black pepper grown in various soil types indicated the definite influence of soil type on AMF colonization. Sandy soil (oxyaquic quartpsamment) harboured maximum root colonization while forest soil (haplic argiustoll) had the lowest. Species of Glomus particularly G. fasciculatum was the predominant AMF associated with black pepper irrespective of soil type. As an exception Acaulospora and Gigaspora species were frequently noticed in sandy soils. Based on the ability of the fungal antagonists to suppress P. capsici in vitro either through mycoparasitism, antibiosis or soil fungistasis, 24 isolates were selected for green house studies. In the further testing isolates A1, A13, A21, A22and A35 significantly reduced the foot rot infection and increased the plant growth. They showed better population build up in the soil and suppressed the P. capsici population considerably. These native antagonists were further tested in combination with selected AMF in the green house and field. Under green house condition, combination of G. fasciculatum x A1 or A21 showed significant influence on growth stimulation, while Is - 6 x A22 recorded lowest mortality of 32.90 per cent due to foot rot incidence as against 97 per cent in control. The dual inoculation of Is - 6 x A21 and Pi - 11 x A1 was highly effective in plant growth stimulation and disease suppression. Both the combination recorded less than 60 per cent infection and mortality due to the disease, while control showed 95.66 per cent infection and plant mortality. Bordeaux mixture and copper oxychloride recorded 66.67 and 59.68 per cent mortality respectively. AMF colonization and multiplication of antagonists were also favoured by dual inoculation. The potential AMF isolates Is - 6 and Pi - 11 were identified as species of Glomus while, the antagonistic isolates A1, A13, A21, A22, and A35 were confirmed as aspergillus fumigatus Fres., Fusarium oxysporum Schlecht. Ex Fr. Aspergillus sydowii (Bain. & Sart.) Thom. & Church, Trichoderma viride Pers. Ex Gray. And Gliomastix murorum (Corda) Hughes respectively. A technique for AMF inoculation to established pepper vines was developed using ‘carrier plants’. Raising sorghum with AMF inoculation around the pepper vines was found effective to achieve intense colonization in pepper roots by the introduced AMF in the field. This technique developed for the pepper vines may be tried for extending to other perennial crops for AMF inoculation. Promising AMF cultures Pi - 11, Is - 6, G. fasciculatum and antagonists Aspergillus fumigatus, A. sydowii, Trichoderma viride were further tested on eight year old established pepper vines following ‘carrier plant’ based AMF inoculation and cowdung - neem cake based antagonist inoculation. The treatment Pi - 11 x A. Sydowii was most effective with no symptom development, followed by Is- 6 x T. Viride or A. sydowii with disease score of 2.0 as against 7.0 recorded for control. The disease score for bordeaux mixture and copper oxychloride application was 3.5 and 3 respectively. Neem cake-cowdung food base was highly favourable for multiplication and activity of fungal antagonists. The amino acids, total sugar and reducing sugar and total phenols and orthodihydroxy phenol content and activity of cellulose and chitinase were influenced by AMF colonization particularly by Is - 6 and Pi - 11. The positive change could be related with the relative disease tolerance recorded for various AMF isolates. The development of native AMF and antagonists through extensive testing in the green house and field and also the technology of AMF inoculation for established pepper vines are the first record of work.
Open Access
Effect of certain biopesticides and irradiation on the developmental stages of myiasis producing flies
(Department of Parasitology, College of Veterinary and Animal Sciences,Mannuthy, 1998) Subramanian, H; KAU; Rajamohanan, K
A study was undertaken on the prevalence of cutaneous myiasis in domestic animals and its control using bio-pesticides and gamma irradiation. The prevalence of cutaneous myiasis in domestic animals was found to be 205 (2.08 per cent) among .the 9861 animals screened. The peak of infestation was noted in the month of January. In host-wise and parasite-wise the highest incidence was noted in cattle (63.41 per cent) and the majority of infestation was produced by Chrysomya bezziana larvae (90.73 per cent). Methoprene at 1 to 50 ppm concentration caused only moderate mortality on larvae but significantly increased the mortality rate on eggs, prolonged the larval phase, increased the formation of larval pupal intermediaries and adult deformities and reduced the adult emergence. Diflubenzuron at 0.5 to 5 ppm caused 55 to 100 per cent larvicidal effect due to lowered chitin content of 18.42 to 52.11 per cent in larval cuticle. Bacillus thuringiensis var israelensis produced only moderate larval mortality at 160 to 800 ppm in myiasis producing flies. Azadirachtin at 10.5 to 15 ppm produced 100 per cent mortality in eggs and larvae. Significant antifeedant, ovipositional deterrent and repellant effects were also produced by Azadirachtin. Among the extracts of Acarus calamus, studied, petroleum ether extract at 2.5 per cent concentration gave 82.5 to 100 per cent mortality of the larvae. Moderate antifeedant, ovipositional deterrent and repellant effects were also noticed. The petroleum ether extract produced 100 per cent sterility at 0.1 to 1 per cent concentration by preventing the development of ovarian follicles. Three day old pupae of myiasis producing flies exposed to r-rays gave excellent sterility effect at 2000 to 4000 rads radiation exposure without any other deleterious effect in the flies. Diflubenzuron at 5 ppm concentration showed the highest larvicidal effect (88.5 per cent) in natural cases of cutaneous myiasis.
Open Access
Prevalence and patholoygy of polioencephalomalacia in goats
(Centre of Excellence in Pathology, College of Veterinary and Animal Sciences,Mannuthy, 1999) Divakaran Nair N; Rajan A
Polioencephalomalacia (PEM) is a significant emerging diseases problem in goats. Although, PEM in goats was recognized and reported as early as 1956, its etiology is poorly understood and symptomatology, pathological features and therapeutic approach have not been well defined and documented. Hence an investigation was undertaken to assess the prevalence of the disease based on the data available from 76 Veterinary hospitals of the state for a period from 1991 to 1994. This data documented revealed an increasing trend in the occurance of the disease and significantly high incidence was recorded in the first five months of which the peak incidence was observed in the month of April. Spontaneous cases of the disease were studied in detail and experiments were conducted taking goat as a model using selected incriminating agents such as Amprolium (350mg/kg body weight), Amprolium and rice gruel (350 mg/kg and ad libitum rice gruel), rice gruel (ad libitum), sodium sulphate (150 mg/kg body weight followed by 500 mg/kg body weight on the 10th day) BHC (2.5 mg/kg followed by 5 mg/kg body weight on the 10th day) and Ficus tsiela Roxb. The experiment was for a period of 45 days. Symptomatology, weight of the animals at fortnightly intervals, weight of the brain, CSF protein concentration, brain autofluorescence, gross and histopathological alterations of the brain and ultrastructural pathology were the markers utilized for evaluating the disease processes. The sodium sulphate, BHC and Amprolium and rice gruel treated group showed symptoms and lesions more or less similar to the spontaneous cases. Only few animals in each group developed the disease such as two in amprolium and rice gruel treated group, four in BHC treated group and three in sodium sulphate group. This showed that individual idiosyncracy plays an important role in the manifestation of the disease. The symptoms developed at different latent periods were not progressive as compared to the spontaneous cases where the symptoms were progressive. The symptoms included lethargy, depression, knuckling at the fetlock, frequent tremors, opisthotonous and loss of eye preservation reflex. Blindness was seen in one of the natural cases. The histological lesions of the brain in all the cases were comparable in different segments of the brain. Mostly it was characterized by diffuse laminar cortical degeneration and necrosis, occasional neuronal swelling glial cell reaction and white matter vacuolation. Vascular changes predominated in the sodium sulphate group and also in the natural cases. There was glial cell response in the form of nodules in sodium sulphate group and natural cases. A predominant perivascular and neuropil accumulation of lymphocytes, gitter cells and monocytes were seen in the natural cases. These were considered as secondary deposition following a toxic degenerative neuropathy. The necrotic focicould well be delineated in few of these cases by the bluish or creamy autofluroscence of the affected brain, but was not found to be of any primary diagnostic value as all the affected brain did not show flurescence. Ultrastructural investigation revealed the basic reaction of the brain tissue to be similar in both the experimental and natural cases except for their intensity. Ultrastructural lesions were characterized by neuronal swelling, membrane lysis, segregation of the filamentous and granular component of nucleolus, cytoplasmic oganellar damage such as fragmentation of RER, partial degranulation of ribosomes, mitochondrial of RER, partial degranulation of ribosomes, mitochondrial swelling, cristolysis and complete disappearance of organelle. Neuropil spongiosis and splitting of myelin at the intraperiod line and formation of multiple vacuolations of the white matter were characteristic. From this observations it was clearly delineated that the primary insult was a biochemical one which caused much damage to the volume control mechanism of the cell and subsequent cellular damage. The CSF protein evaluation revealed high protein level in the spontaneous cases whereas in the experimental cases, the concentration remained within the normal range indicating that it has no diagnostic value. In this investigation it has not been possible to induce PEM with Amprolium even at a dose rate of 350 mg/kg bodyweight and it was proved that amprolium is not a cause for PEM. Rice gruel ad libitum was found to be tolerated by the animal except one which showed dullness and abdominal distension towards the end of the experiment. Diffuse neuronal degeneration was observed in the brain of this animal. Based on this observation it was concluded that rice gruel consumption every day as a component of the concentrate feed in goats might not cause any detrimental effects and the problem comes only when it is fed in large quantities on a single day. Ficus tsiela Roxb. Though produced vascular damage and diffuse neuronal degeneration in one of the experimental animals, goats were found to be highly resistant to ficus tsiela Roxb. Toxicity and the variation in the susceptibility of different species to this toxicity was brought to light. From this investigation it was also clarified that sodium sulphate, BHC, rice and amprolium could be initiating agents of PEM under certain circumstances and no single cause seems to be responsible for PEM.
Open Access
Monitoring and management of the pest complex of bitter gourd (Momordica Charantia L.)
(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1999) Nandakumar, C; KAU; Saradamma, K
Surveys were conducted in 1995-96 among one hundred bitter gourd farmers in Thiruvananthapuram district. Information on the personal and socio- economic characteristics of the farmers was gathered. Field visits indicated that among the pests at flowering, the jassid, H.phycitis and leaf feeder, D. indica were important. At early harvest, the jassid and fruitfly B. cucurbitae were the major pests. Among the natural enemies observed, the potential ones were Cjohnsoni (parasite on Hseptima), I.scutellare, Msexmaculatus and Snubilis . (predators on A.gossypii). Mosaic was severe in 12 per cent of the plots. Sixty two per cent of the farmers used a combination of mechanical, cultural and chemical measures against pests. Most common pesticides used belonged to the organophosphate group. Farmers in general adopted injudicious methods of chemical control. Seventy per cent farmers relied on mass media and interpersonal cosmopolites for information on plant protection. The most important constraint perceived by farmers was the high cost of inputs viz., plant protection chemicals, manures and fertilizers. Monitoring of fruit fly incidence using Biosense stikatrap (lure) indicated the maximum catch at eleven weeks after sowing. Ten carbofuran smeared banana fruit traps (in yellow coloured coconut shell) were found to be more efficient than one Biosense trap in trapping the fruit fly. 2 Studies on seasonal incidence of the pests and their natural enemies from 1995 to 1996 indicated that they were more from November '95 to April '96. In studies on the assessment of potential natural enemies of pests, the biology and efficacy of Cjohnsoni against epilachna beetle was observed. Among the predators viz., Iscutellare, Msexmaculatus and S.nubilis whose biology and feeding potential was studied, Msexmaculatus was observed as the most efficient predator of aphids. In another set of experiments, the effects of botanicals and chemical pesticides on pests and their natural enemies were studied. The antifeedant effect of botanicals on third instar Hseptima grubs indicated that neem seed oil (three per cent) and nimbecidine (0.40 per cent) were effective. Estimation of the comparative effect of chemical pesticides against the fourth instar Hseptima grubs showed that carbaryl and dimethoate were more effective than quinalphos and malathion. Toxicity studies of botanicals and chemical pesticides to Msexmaculatus grubs and Cjohnsoni adults as well as parasite emergence from treated larval! pupal Hseptima hosts indicated that botanicals were safe whereas, the chemicals were toxic to the natural enemies. Based on the above experiments, the botanicals viz., neem seed oil three per cent, nimbecidine 0.40 per cent and the chemical pesticides,carbaryl 0.15 per cent and dimethoate 0.05 per cent were selected for the pest management trial in bitter gourd. The reaction of five bitter gourd varieties viz., Priya, Arka Harit, Preethi, Priyanka and local to pests was tested in a field trial. Based on pest infestation and yield, Preethi was selected for the pest management trial. 3 The pest management trial was conducted for two seasons (January to April, 1996 and 1997). The results indicated that combination of botanical with chemical pesticide was the best in pest control. Based on the results the following recommendations were suggested as part of IPM strategies in bitter gourd. 1. Use variety 'Preethi' (MC-84) for planting 2. Basal drenching of combination of nee m seed oil three per cent soap emulsion with either dimethoate (0.025 per cent) or carbaryl (0.075 per cent) prior to seeding. This is recommended in areas where pests like pumpkin beetles are endemic. 3. Need based application of above till fruit set to control pests. 4. Apply fungicide (Mancozeb) to control foliar disease (downy mildew). 5. Monitor fruit fly incidence using lure trap. Set yellow painted coconut shell trap's containing carbofuran smeared banana (palayankodan) alternated with carbofuran poisoned ocimum I jaggery (2m spacing) at flowering till final harvest. 6. After fruit set, use (need based) a combination of neem seed oil three per cent soap emulsion and dimethoate 0.025 per cent.
Open Access
Standradisation of organic and inorganic fertiliser comnbinations for maximising productivity in bitter gourd (Momordica Charantia L.)
(Department of Agronomy, College of Agriculture, Vellayani, 1999) Rajasree, G; KAU; Raghavan Pillai, G
An investigation was carried out during 1995-96 and 1996-97 at the Instructional Farm attached to College of Agriculture, Vellayani to study the efficacy of different levels of N applications (200, 250 and 300 kg N ha") in different ratios of organic - chemical N substitutions (l : 1, 1:2 or 2: 1) at different frequencies (F I - full quantity of organic source as basal, F2 - organic source at basal and at 40th and 70th DAS, F3 - organic source as basal + fortnightly equal splits and chemical N source as basal + fortnightly intervals in equal splits in all the frequencies) of application. Two different organic sources ie. farm yard manure and poultry manure were used in two simultaneous experiments viz. Experiment I and 11. The experiments were separately and simultaneously laid out as confounded 33 design in 9 plot blocks with 2 replications, confounding LR2F in RI and LRF2 in R 11. Higher levels ofN nutrition was found to reduce days taken to flower in farm yard manure applied trial while sex ratio was narrowed at 90 DAS in poultry manure applied experiment. Higher jassid population was noticed at 60 DAS when higher levels ofN was supplied predominantly through organic source as farm yard manure. Fungal leaf spot infestation was higher with the application of200 kg N at 90 DAS and was also more with split applications of both farm yard manure and chemical N source at early stages of growth. Full basal application of poultry manure was found to promote the per hectare yield of fruits, fruit yield planr I and number of fruits planr I compared to its split applications. When highest level ofN (300 kg) was supplied through 2: 1 ratio of organic - chemical N substitution using poultry manure as organic source, it effectively increased the fruit yield and number of fruits plant". 2 Shelf life of fruits at room temperature was more when nutrient N was supplied through 2: 1 ratio of organic - chemical N substitution using farm yard manure or poultry manure as an organic source. When N level was increased beyond 200 kg, shelf life of fruits at room temperature slightly decreased even when it was predominantly supplied through organic source of farm yard manure or poultry manure. Similar trend was noticed at refiigeratory condition too. Nitrogen nutrition showed depressing effect on ascorbic acid or vitamin-C content of fruits in Experiment I. Iron content in fruits was more with the application of 200 or 300 kg N level in Experiment ll. When 300 kg N was applied through a major source of poultry manure (2: 1 ratio) it produced higher iron content in fruits. Higher nitrogen levels or nitrogen nutrition through 2: 1 ratio of substitution promoted the soil bacterial population in both Experiment I and II. Full basal application of farm yard manure or poultry manure favourably influenced the soil bacterial population. Nitrogen nutrition showed depressing effect on fungal population of soil in Experiment I while it stimulated the fungal growth in Experiment 11. Soil actinomycetes population was higher with 2: 1 substitution ratio using farm yard manure as organic source ofN. When farm yard manure or poultry manure as organic source was used in equal or higher proportion with chemical N source, it showed moderating effect on the soil acidity. Full basal application of farm yard manure also enhanced the soil pH from the acidic range and the organic carbon content. Application of higher levels ofN increased the net loss ofN, P and K of soil in both the Experiment I and H. Net loss ofN was higher with 1:2 ratio ofN substitution or few or more split applications of organic source (farm yard manure) in Experiment 1. Net loss of nutrients was moderated during the second year of field experimentation. Nitrogen 3 nutrition in 1:2 ratio of substitution enhanced the net loss ofN in Experiment H. Nitrogen nutrition through 2: 1 ratio ofN substitution or basal + 2 split doses of farm yard manure increased the net loss of P in soil. The net loss of K in soil was more when farm yard manure and chemical N sources were applied in 2: 1 or 1: 1 ratio of substitution. Net gain of K was observed in Experiment H, when chemical N source was substituted in higher proportion compared to poultry manure or when full dose of poultry manure was applied as basal dressing. Higher levels ofN application have resulted in negative net energy returns or energy loss in both the experiments. The 1: 1 or 1 :2 ratio ofN substitution caused higher net energy losses in Experiment I while split applications of poultry manure resulted in more energy loss in Experiment H. Total energy output was higher with full basal application of poultry manure in Experiment I. Energy ratios registered a negative value and was higher with low level ofN application in Experiment I and II. Higher gross returns were obtained when full quantity of poultry manure was applied as basal dose in Experiment 11. Application of300 kg N through 2: 1 ratio of organic- chemical N substitution registered higher gross returns in Experiment II. Net returns was higher when 200 kg N ha! was applied. Increasing N level beyond 200 kg was not economic in Experiment I using farm yard manure as organic source. When full quantity of poultry manure was applied completely as basal dose, higher net returns was obtained in Experiment H. Benefit-cost ratio decreased when N level was enhanced beyond 200 kg ha' in Experiment I. Higher benefit - cost ratio was recorded when poultry manure was applied in full dose as basal dressing. Study revealed the favourable influence of organic sources; farm yard manure and poultry manure on fruit quality, shelf life and soil properties. The suitability of poultry manure as organic source for vegetable cultivation was also established by this study.
Open Access
Insect pest natural enemy- host plant interaction studies with special reference to the brown planthoper nilaparvata lugens(Stal.)
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1999) Haseena, Bhaskar; KAU; Joy, P J
Field surveys were conducted in Kole land and Kuttanad to assess the population of rice BPH, Nilaparvata lugens (Stal) and its natural enemies. Field investigations on the population dynamics of BPH and its natural enemies were carried out on susceptible (Jaya), moderately resistant (Jyothi) and resistant (Kanakom) rice varieties at the rice fields of Rice Research Station, Moncompu during 1997-98. The influence of these varieties on the biology of the pest, the biocontrol efficiency of the major natural enemies and the biology of the mirid predator Cyrtorhinus lividipennis Reuter was studied in the laboratory. Histological and chemical investigations were undertaken to evaluate the factors that contribute to the resistance/susceptibility in them. Results of field survey in Kole land revealed that the population of BPH was far below the economic threshold level (ETL). In Kuttanad, in kayal area during Rabi season and in karappadam tract during Kharif season outbreaks of BPH occurred in some localities due to the indiscriminate use of insecticides resulting in the mortality of natural enemies. The results of the study on population dynamics revealed that the BPH population was significantly high on the susceptible J aya and low on the resistant Kanakom with the population reaching a peak from February to March. The predatory complex of the BPH comprised of the rnirid Cyrtorhinus lividipennis, Lycosa pseudoannulata, Tetragnatha maxillosa, Atypena formosana, Microvelia douglasi atrolineata, Pseudogonatopus sp. and Ophionea nigrofasciata. C. lividipennis was the most predominant predator regulating the hopper population and there exists a density dependent host-predator relationship. The population of the mirid predator on Jaya and Kanakom did not differ significantly. The prey-predator ratio was lowest on the resistant variety and highest on the susceptible variety. Of the weather parameters studied, the minimum -. temperature showed a highly significant negative correlation with the population of N. lugens in all the varieties. BPH reared on the resistant variety recorded longer nymphal duration, decreased nymphal survival and shorter adult longevity indicating the prevalence of antibiosis in the variety. Lesser number of eggs laid, longer pre-oviposition period and shorter oviposition period recorded on Kanakom indicate the antixenosis factor in it. Macrpterous forms of BPH did not develop on the variety . The predator C. lividipennis and Micraspis sp. fed more BPH when reared on the resistant variety. The veliid bug M. d. atrolineata, the spider L. pseudoannulata and the dryinid Pseudogonatopus sp. predated significantly more BPH nymphs on resistant variety at a higher prey density only. However, the dryinid parasitoid consumed significantly fewer number of hoppers on Kanakom at the higher host density. C. lividipennis recorded longer nymphal duration, shorter adult longevity and low fecundity when fed on BPH reared on Kanakom which can be attributed to the low fecundity of N. lugens on Kanakom leading to less availability of food to the mirid. Nymphal duration and adult longevity of C. lividipennis did not vary between the varieties Jaya and Jyothi. Well developed bundle sheath with more frequently distributed schlerenchyma tissue in the culm of the resistant variety seemed to impart resistance in Kanakom along with thicker cuticle. Higher amounts of silica, Zn and Mn and lower amounts of N, K, Ca and Mg were recorded in the culm of the resistant variety compared to moderately resistant and susceptible varieties. The findings strongly suggest the mechanism of antibiosis and antixenosis in the resistant variety Kanakom.
Open Access
Production dynamics of ginger (zingiber officinale R.) under varying levels of shade, nutrients and triazole
(Department of Horticulture, College of Agriculture, Vellayani, 1999) Ajith Kumar, K; KAU; Jayachandran, B K
The experiments were conducted at the Coconut Research Station, Balaramapuram, during 1996-97 and 1997-98 to study the production dynamics of ginger under varying levels of shade, nutrients and triazole. The specific objectives were to study the production potential of ginger under open and different shade levels, to standardise optimum dose of nutrients and mulch for ginger intercropped in coconut garden and to evaluate the efficacy of triazole in the improvement of yield and other desirable characters. The effect of shade on growth and yield contributing parameters viz., tiller number, leaf number, leaf area, leaf dry weight, root spread, root volume, rhizome spread, rhizome thickness, number of rhizomes, leaf thickness, stomatal frequency, DMP and LAI under 20 and 40 per cent shade levels exhibited significant superiority in pot culture study. In pot culture study: maximum fresh ginger yield of 450.0 and 396.3 g plant" were resulted from plants kept under 20 and 40 per cent shade levels respectively. This was 27.4 and 12.2 per cent higher compared to open- condition. The dry ginger yield of 94.5 and 89.2 g plant" were obtained from plants kept under 20 and 40 per cent shade levels respectively. This was 27.8 and 20.7 per cent higher compared to open condition. However, the dry ginger yield obtained from 60 and 80 per cent shade levels were significantly lower compared to open. The shade levels 20 and 40 per cent gave the highest shoot dry weight of 48.9 and 53.6 g plant" respectively. Volatile oil content showed an increasing trend with increasing levels of shade in pot culture study. Maximum NVEE was recorded under 20 and 40 per cent shade levels. Highest starch content was obtained from 20 per cent shade level. Crude fibre gradually reduced with increase in shade levels. The field trial on nutrient requirement of ginger as intercrop in coconut garden revealed that, NPK application at higher levels increased plant height, tillering, leaf number, leaf area, DMP and chlorophyll content. Physiological parameters like, NAR, CGR and RGR were promoted by higher rates of nitrogen application. The results revealed that, N: P, N : K and P : K ratios of l.5 : 1, l.5 : 1 and 1 : 1 respectively, were ideal to get maximum fresh ginger yield. Application of 150 kg N, 100 kg P20S and 100 kg K20 ha-l gave maximum net profit ofRs. 96605/- and Rs. 99227/- during first and second year respectively. The net profit when the existing recommendation of 75 kg N, 50 kg P20S and 50 kg K20 ha-l was Rs. 54960/- and Rs. 54730/- during first and second year respectively. Hence the study suggests that the existing recommendation (75 kg N, 50 kg P20S and 50 kg K20 ha") has to be doubled (150 kg N, 100 kg P20S and 100 kg K20 ha-l) for increasing the productivity of ginger intercropped in coconut garden. Increased rate of fertilizer application did not influence the quality of the produce. Plant uptake of NPK increased with higher levels of fertilizer application. The field experiment on mulch requirement of ginger intercropped in coconut garden showed that the rhizome yield from plots mulched with 30.0, 22.5 and 1 =r. 0 t ha' were on par. Therefore the mulch requirement of ginger intercropped in coconut garden can be reduced from 30 t ha-l to 15.0 t ha-I Application of triazole did not exhibit any beneficial effect on yield and quality of ginger.
Open Access
Effect of iron and vitamin supplementation on iron profile of anemic adolescent girls
(Department of Home Science, College of Agriculture, Vellayani, 1999) Kavita, M S; KAU; Prema, L
The study entitled, "Effect of iron and vitamin supplementation on iron profile of anemic adolescent girls", was conducted to assess the magnitude of iron deficiency anemia among adolescent girls; to find out the direct and indirect effects of causative factors and to evaluate the relative effect of supplementation of iron with vitamins on the iron status of anemic adolescent females. The study was limited to Neyyattinkara, Nedumangadu and Trivandurn Taluks of Trivandrum district. Rapid assessment technique was administered to determine haemoglobin and to indentify 225 adolescent girls suffering from iron deficiency anemia (with Hb ::::;; 12g1dl). Socio economic status of the girls was determined by using a suitably structured schedule while nutritional variables responsible for the incidence of anemia were determined through assessing their mean food intake by 24 hour recall method and by ascertaining their anthropometric measurements using universally accepted techniques. Clinical examination was conducted to assess the health variables responsible for iron deficiency anemia. A metabolic experiment of two months duration was conducted to find the effect of iron and vitamin supplementation on iron profile of the moderately anemic girls. For this, the basal diet which gave RDA of nutrients was supplemented by 60 mg iron and 500 ug folic acid, 600 /-lg equivalent vitamin A, 1.2 mg equivalent vitamin B~ and ~ 40 mg equivalent vitamin C in different treatment groups either in the form of tablets 351 Supplements in the form of tablets produced highest and rapid changes in haematological and iron profile while the greatest positive changes in growth and physical endurance were observed when the supplements were given in the form of food. Hence for proper iron nutriture, iron source with high bioavailable iron is necessary along with balanced intake of other nutrients.

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