RESUMEN
To evaluate the effect of Trichoderma spp. on radial growth of Sclerotium rolfsii, three species of Trichoderma viz., Trichoderma viride, Trichoderma harzianum and Trichoderma longibrachiatum were selected. The results from this experiment revealed that T. viride (TvL), T. harzianum 4 (Th 4) and T. harzianum 14 (Th14) isolates were found effective and showed lowest radial growth of 3.50 cm and highest per cent inhibition (56.25%) of S. rolfsii but were statistically on par with each other. The highest radial growth (4.23 cm) and lowest per cent inhibition (47.1%) were recorded with T. longibrachiatum (Tl2). Results from non-volatile assay indicated that irrespective of concentration, culture filtrate of T. viride (TvL) was found to be most effective; recorded lowest radial growth and highest per cent inhibition followed by T. harzianum 14 (Th14) and T. harzianum 4 (Th4).
RESUMEN
To evaluate certain plant extracts on development of Sclerotium rolfsii causing stem rot in groundnut, we conducted an in vitro experiment in Department of Plant Pathology, Agricultural College, Bapatla. For this, we selected eight plant species viz., Ashoka (Polyalthia longifolia), Garlic (Allium sativum), Ginger (Zingiber officinalis), Neem (Azadirachta indica), Seetha Phal (Annonas squamosa), Tulasi (Ocimum sanctum), Milk weed (Calotropis gigantean) and Peri Winkle (Vinca rosea) and are tested at 10% concentration. Among these plant extracts, clove extract of garlic was most effective and recording lowest mycelial growth (0.0 cm) and highest per cent inhibition (PI) (100%) in both sterilized and un-sterilized conditions. In sterilized condition, garlic followed by tulasi (4.62 cm, 48.70 PI) and neem (7.38 cm & 17.9 PI) were recorded the lowest mycelial growth and highest per cent inhibition over control, respectively. In un-sterilized condition, garlic followed by ginger (2.43 cm & 72.96 PI) and tulasi (2.52 cm & 72.04 PI) were recorded the lowest mycelia growth and highest per cent inhibition over control, respectively.
RESUMEN
To know the efficacy of bio-control agents on growth of Sclerotium rolfsii causing stem rot of groundnut, an in vitro study was conducted in the Department of Plant Pathology, Agricultural College, Bapatla. For this, three Trichoderma spp., two Pseudomonas fluorescens isolates and one Bacillus subtilis were selected as biocontrol agents. We observed that, there is a significant difference among all the treatments. The lowest radial growth (1.9 cm) and highest per cent inhibition (79.26%) were recorded with T. viride PDBC isolate followed by T. harzianum 4 (2.3 cm and 74.81%) and Trichoderma harzianum PDBC (2.6 cm and 70.74%) isolates, respectively. Among the bacterial isolates, lowest radial growth (4.6 cm) and highest per cent inhibition (48.89%) of S. rolfsii were recorded with Bacillus subtilis PDBC isolate. But the highest radial growth (7.6 cm) and lowest per cent inhibition (15.56%) was recorded with P. fluorescens SPA1 isolate.