Browsing by Author "Santha Kumari, P"

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Effect of nitrogen, phosphorus and potassium nutrition on incidence and intensity of grey blight of coconut
(Department of Plant Pathology, College of Agriculture, Vellayani, 2003) Subramanyan, K; Santha Kumari, P
The investigation on the "Effect of nitrogen, phosphorus and potassium on incidence and intensity of grey blight of coconut" was conducted during 2001-2002 at the Coconut Research Station, Balararnapuram, Thiruvananthapurarn, Kerala. The coconut palms cultivated in the Permanent Manurial Trial experimental plot of the station was used for the studies. The pathogen was isolated from the infected leaf tissue by the standard tissue isolation technique. Cultural and morphological studies confirmed the identify of the pathogen as Pestalotiopsis palmarum (Cooke) Stey. Among the different artificial media tried potato dextrose and sucrose were the best for growth and sporulation of the pathogen. Conidial morphology of fungus was studied on six media. The fungus produced largest conidia and appendages on PDA and PSA, while those produced on PDA had the maximum breadth. The maximum incidence and intensity of grey blight was observed in the month of August. During the subsequent months it declined and the least was observed in February . . The incidence and intensity of the disease was correlated with different levels of NPK fertilizer application and nutrition status of palms. Higher rate of nitrogen, phosphorus and potash application in soil resulted in higher rate of these nutrients in the leaf samples and higher rate of the disease. The disease intensity was maximum In palms supplied with the treatment combination N )P2K2 and minimum in N2P2Ko. The highest disease incidence and intensity were observed when the relative humidity was above 83 per cent. The maximum temperature at this period was 29.7oC and the minimum temperature 20.7()C. The rainfall during this period was 243.3 mm. These weather parameters were observed during the month of August. The lowest disease incidence and intensity was observed when the relative humidity was 77.2 per cent. The maximum temperature was 31.4°C and minimum temperature 22.3°C. Rainfall during this period was 15 mm. These weather parameters were recorded during the month of February. There was a positive correlation on the incidence and intensity of grey blight with rainfall, relative humidity and wind speed where as a negative correlation was observed with temperature. Nutrient composition of the healthy leaf tissue indicated that with an increase in the nitrogen level, there was a corresponding increase in the nutrient status of major, secondary and micronutrients. A similar trend was noticed with phosphorus and potassium also. However, with increase in potassium level there was a corresponding decrease in the magnesium content. Similarly with an increase in phosphorus a decrease in zinc and boron content was observed both in healthy and diseased leaf tissues. Both in two way and three way interactions, involving NP, NK, PK and NPK the composition of nutrients of healthy as well as in diseased leaves increased with increase in the levels of nitrogen, phosphorus and potassium. Chlorophyll, total sugar, amino acid and phenol contents in healthy tissues were found to be high with higher levels of fertilizer application.
Etiology and ecofriendly management of fungal diseases of thippali ( Piper longum L)
(Department of Plant Pathology, College of Agriculture, Vellayani, 2007) Poornima, R; Santha Kumari, P
A survey was carried out at the medicinal garden of College of Agriculture, Vellayani and medicinal garden of Ayurveda Research Institute, Poojappura, Thiruvananthapuram to study the diseases associated with Piper longum L. (Indian long pepper or thippali). The major disease observed was anthracnose caused by Colletotrichum gloeosporioides (Penz.) Penz and Sacc. Pathogenicity test proved that C. gloeosporioides was the pathogen associated with the disease. Cross inoculation studies conducted using C. gloeosporioides isolate of thippali, black pepper and betel vine - the sister plants – showed that the thippali isolate was highly host specific. The colony and conidial morphology of the three isolates also showed considerable difference. C. gloeosporioides of thippali had very small conidia and the culture was also found to be shy sporulating. Studies on the survival of C. gloeosporioides showed that the pathogen survived for 105 days in the infected leaves, under laboratory conditions. In the soil, it survived for 150 days. Of the eleven fungal and four bacterial isolates tested against C. gloeosporioides, T. viride and A.terreus were found to be most effective under in vitro condition. Among the different resistance inducers tested in vitro, SA (1 g/l) was selected for field evaluation, as it had no direct action on the pathogen. Of the two plant based chemicals tested, Ovis reported the highest suppression of the pathogen. These four eco friendly materials selected from the in vitro studies and neem cake were tested in the field to determine their effectiveness in controlling the disease. Their combinations were also studied. Among the different eco friendly materials tested in the field, treatment T12 (T2T5 - A. terreus + neem cake) was found to be best in disease suppression at 45 DAT. Estimation of DRE showed that PO and PPO activity was highest in T3 (Ovis) where as PAL activity was maximum in T1 (T. viride). Combination of treatments revealed that maximum PO activity was in treatment T14 (T3T5 - Ovis + neem cake).The PPO and PAL activity was maximum in T7 (T1T3 - T. viride + Ovis).
Occurrence of rotting disease in anthurium
(Kerala Agricultural University, Vellanikara, 2001) Santha Kumari, P; Mary, C A; Dhanya, M K
Studies on the fungal diseases of ornamental plants
(Department of Plant Pathology, College of Agriculture, Vellayani, 1980) Santha Kumari, P; Chandrasekharan Nair, M
The survey was conducted to study the occurence of fungal pathogens on common ornamental plants grown in the college campus. Collototrichum gloeosporioides, Cercospora sp, Pestalotia sp, Coryaespora sp, Curvularia sp,Sooty mould and red rust were the common pathogens noticed. Of these, leaf spot disease due to S gloeosporiodes forms the major disease affecting majority of the ornamental plants. Symptamatology, morphology and cultural characters of the seven isolates of S glocosporioides were made. The Characteristics of these isolates compares well and agreed with those reported in literature.