Abstract:
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).
