INVESTIGATION ON FIELD DISEASES OF COMMERCIALLY CULTIVATED MEDICINAL CROPS IN NATORE, BANGLADESH

Abstract

The present investigation was carried out in three different fields of medicinal crops at Lakshmipur-Kholabaria village in Natore District, Bangladesh during the period from April, 2013 to February, 2014. The investigation was conducted with an effort to identify the major and minor diseases, their cause(s) and to measure the disease incidence and disease severity of major diseases of selected medicinal crops. This was the first methodological investigation to find out the diseases of medicinal crops in Bangladesh. In the present research, five commercially cultivated and economically important medicinal crops viz. aloe vera (Aloe barbadensis), winter cherry (Withania somnifera), asparagus (Asparagus officinalis), malabur nut (Adhatoda vasica), basil (Ocimum basilicum) were selected for disease investigation. Data were collected from three different fields at Lakshmipur-Kholabaria village in Natore district in three different seasons of Bangladesh. Plants were examined In situ for disease symptoms as well as samples being collected for laboratory analysis. Causal organism(s) were identified using morphological characteristics, and where necessary with compound microscope. According to disease incidence and severity, the major disease of aloe vera was Alternaria leaf spot where the highest disease incidence and disease severity were 90% and 76.67%, respectively. Major disease of winter cherry was leaf roll and the highest disease incidence was 50%. In case of asparagus, major disease was stem rust and the highest disease incidence and severity were 33.33% and 11.67%, respectively. For malabur nut, major disease was Cercospora leaf spot where the highest disease incidence was 63.33%. In case of basil, major disease was leaf spot and the highest disease incidence and severity were 43.33% and 53.33%, respectively. It was found that during rainy season the incidence and severity of most of the diseases were high.