Title : Bioresources, fungicides and SAR chemicals in integrated management of Alternaria branch rot of carnation
Alternaria branch rot or leaf spot of carnation was reported as a serious disease in carnation during 2016-17 in Himachal Pradesh-India causing maximum disease severity of 26.25% in Chail of Solan district. The symptoms on leaves initiated from the margin, tips as small purple lesions, turning grayish-brown as it matures and get blighted. Spreading later on to the stem, flower buds and even the immature flowers develops characteristic water soaked areas. Considering to the heavy losses annually and the adverse effect of the chemicals on environment, the present study was formulated with the objective to include alternative strategies in managing this devastating disease with the use of ecofriendly means. Various bioresources and SAR chemicals were exploited to manage the disease to keep the environment clean and soil fertile. Out of the bio-products, neemazal followed by cow urine were found superior by giving cent per cent and above 95.37% inhibition at higher concentrations of 30% compared to lower conc.10, 20% .Cloves extract of garlic yielded good results in suppressing the growth of the fungus upto the extend of 60.80% .The latex of agave and fruit rind of the soapnut gave 50.60 and 47.09 per cent inhibition in mycelia growth. Maximum inhibition (91.42%) in mycelia growth was obtained with neem oil and mint oil (88.52%).Whereas in fungicides score ( difenoconazole ) and contaf ( hexaconazole) completely inhibited the growth at all concentrations amongst the systemic fungicides which was followed by fungicide, dithane M-45 ( mancozeb) a non-systemic in nature under in vitro assessments. In field trail, the best treatments along with SAR ( systemic acquired resistant ) chemicals revealed the minimum extent of the disease severity with four applications of the sprays in score, which was followed by Contaf and combined treatments of BABA (β amino butyric acid)+ neemazal+garlic extract + neem oil and Chitosan+ neemazal+garlic extract + neem oil .The combined treatments also enhanced all the plant growth parameters in addition to lowering of the disease level to minimum threshold.