BANGLADESH JOURNAL OF FOREST SCIENCE
A Half-yearly Peer Reviewed Journal of Bangladesh Forest Research Institute
A Half-yearly Peer Reviewed Journal of Bangladesh Forest Research Institute
Five Trichoderma strains such as T. virens IMI-392430, T. pseudokoningii IMI-392431, T.
harzianum IMI-392432, T. harzianum IMI-392433, T. harzianum IMI-392434 were tested for efficacy to
inhibit and overgrowth of mycelia of Fusarium solani, a causal agent of root rot of Ashwagandha on
potato dextrose agar (PDA) medium. Duel culture technique showed that all Trichoderma strains
effectively inhibited and overgrew mycelia of the pathogen, especially T. harzianum IMI-392432
providing the highest percent of inhibition of radial growth (PIRG) (69.32 %) and overgrowth mycelia
(59.28 %). Liquid culture filtrates having 75% concentration extracted from 30-day-old T. harzianum
IMI-392432 showed the highest percent inhibition of mycelia growth (PIMG) value of 76.23% by using
normal poison agar technique. Further, highest percent inhibition of conidial germination (PICG) (82.86
%) of the pathogen was exhibited by T. harzianum IMI-392432 at same culture and concentrations. In this
study it was observed that different Trichoderma strains have good antagonistic effect on Mycelial growth
and conidial germination of F. solani. In each case, T. harzianum IMI-392432 performed the best
bio-control agent against F. solani causing root rot disease of Ashwagandha.
In 1990, a serious root rot disease was observed in different strip plantations of Court Chandpur-Subdalpur railroad, Jessore-Benapole highway and Jessore-Satkhira road of greater Jessore district. These plantations were covered with trees such as Cassia siamea, Acacia
auriculiformis, A. nilotica, Albizia procera, Leucena leucocephala and Dalbergia sissoo. The affected trees died in patches showing wilting symptoms. C. siamea, A. auriculiformis and A. procera were affected most, whereas A. nilotica, L. leucocephala and D. sissoo were least affected. The leaves of the diseased trees became brown, dried up and remained attached to the dead branches. After excavation of roots, whitish mats of mycelia were observed on the branch and anchor roots of the trees. Typical fruit bodies were seen on the collar region, exposed roots and on Clerodendruni viscosum and Glycosmis pentaphylla situated at the vicinity of the infected trees (Figs. 1 and 2). The bark of roots were rotted and, in most cases, the rotting was extended up to the collar region. The fungus responsible for the disease was isolated and identified as Fomes lignosus (Klotzsch) Bres. Heavily infected trees were removed from the sites. Basal area covering one metre radius of each diseased tree was drenched with 2% commercial formalin. The second spray was given 15 days after the first. The sprays, however, could notsave the diseased trees butfurtherspread ofthe disease symptom was checked.
Sandal wood, Sautalum album L. contains fragrant oil in the scented heartwood which issold by weight, and perhaps it is the most precious
wood in this part of the world (Troup 1921). However, Bangladesh imports sandal wood for commercial purpose. Recently, the Bangladesh
ForestResearch Institutehad undertaken research work on the silvicultural aspects of this species to help raise its commercial plantations. The Forest Department has undertaken an afforestation project with this species. As a consequence, hundreds of seedlings were raised in polybags in January, 1993. A serious root rot disease was observed in late February of the same year.
The typical symptom of the disease was manifested through the gradual browning of the leaves of the seedlings. Brown spots appeared first on the branch and tap roots, which later turned black. The leaves of the infected seedlings lost their freshness and began to die out with the stem standing erect. The disease caused 50% mortality of the seedlings within 3-5 days. One fungus, Fusarium moniliformae Sheld. was consistently isolated from the samples. A pathogenicity test confirmed that the fungus was the pathogen of the root rot.
The root rot ofsandal wood seedlings was successfully controlledby the use of DithaneM-45 @ one gram/I of water. The fungicidal mixture was sprayed over the diseased and healthy seedlings in such a way that the mixture could reach the rootsystem. A second spraywas applied after an interval ofone week. Arrangermentswere also made for allowing sufficient light on the seedlings for about six hours a day.
This disease is a new record on sandal wood in Bangladesh. Although root rot is a common phenomenon in our forest nursery, the disease was indeed a serious one. No report of such kind of root rot is available. Excess moisture causes damping-off to the sandal wood seedlings (Troup 1921). However, it was not a case of damping-off. F. moniliformae is mainly a soilbome fungus which can cause leaf blight of maize, foot rot of rice and mango floral malformation (Rangaswami 1988). It also causes pre-and post-emergence seedlings blight of maize (Baruah et al. 1985). Rahman et al. (1980) isolated F. moniliformae from agar, Aquillaraia agallocha tree. The fungus can survive in soil for a long period, and isfound in fields having general deficiency of water (Singh 1983). In Bangladesh, January and February are the months of dry and cold period of the year. So, this may be the favourable time for its sporulation and infection in our country.
Welcome to the Bangladesh Journal of Forest Science (BJFS) – a leading platform for advancing the knowledge and understanding of forest science in Bangladesh and beyond. Established with a commitment to excellence, BJFS serves as a cornerstone for researchers, practitioners, and enthusiasts dedicated to the sustainable management and conservation of forest ecosystems.
