Four experiments were conducted at the Plant Pathology Division of Bangladesh Rice Research Institute (BRRI), Gazipur both in rainfed and irrigated rice ecosystems during 2005 to 2006. The isolate of D. angustus used in all experiments was collected from an infested field of rice cv. BR3 in Gazipur District, Bangladesh. Infected stems were cut into small species, placed in a Petri-dish, and immersed into distilled water for approximate 4 h to release nematodes from the plant tissue. Nematodes were then collected onto a sieve (0.02 mm-pores) and quantified using a compound microscope (Nikon AFX-IIA, Japan). This population was aintained and increased by inoculating nematodes onto rice cv. BR3 and placing plants in a glass house (25 to 28°C; RH 80%) at BRRI. For the field experiments, two popular rice varieties cv. BR11 and BRRI dhan28 (susceptible to ufra) were used in the rain-fed and irrigated ecosystems, respectively. Seedlings of each variety were propagated on a small piece of medium low-land. Clean, healthy and mature seeds (germination rate >85%) were pre-germinated for 24 h in a moist-plastic tray in the dark at 28°C before sowing in the seedbed. Twenty days after sowing (DAS), the seedlings were inoculated by spreading D. angustus infested plant material (small pieces of stems) from cultures into the seedbed of each pot. Following the inoculation method, each seedling was received approximate 100 nematodes (Rahman and Evans, 1988). For the effect of timing of application of furadan 5G in soils, 2 experiments were conducted in the rain-fed and irrigated ecosystems. Furadan applied at 1 kg/ha was incorporated into the soil (by hand spreading) at 40, 30, 20, 10, 0 days before transplanting (DBT) D. angustus infected seedlings. There were 6 treatments: T1: furadan 5G 40DBT, T2: furadan 5G 30DBT, T3: furadan 5G 20DBT, T4: furadan 5G 10DBT, T5: furadan 5G 0DBT and T6: healthy (control). For the management of D. angustus, 2 field trials were conducted to evaluate the 3 granular nematicides, sunfuran 5G, edfuran 5G and forwafuran 5G in both the environments. The information about source, registrations status and chemical names of the tested nematicides are shown. The treatments were: T1: sunfuran 5G, T2: edfuran 5G, T3: forwafuran 5G, T4: furadan 5G, T5: control (diseased), T6: control (healthy). The rate of application of all the nematicides was 1 kg ai/ha and all nematicides were incorporated into the soil at the time of transplanting. Furadan 5G was used as a standard check. For all the field trials, intercultural operations including fertilization, weeding and irrigation were done in the field (BRRI, 2003). Thirty five-day-old seedlings with visible chlorotic symptom on the leaf sheath were transplanted in the plots following 2 to 3 seedlings/hill. The distance between hill to hill and row to row was 20 cm. The plot size was 2 x 3 m and each plot was surrounded by a 20 to 25cm high mud plastered levee to prevent the spread of D. angustus. Experiments were laid out in a randomized block design (RBD) with 4 replications. The whole plot was cut and diseased panicles were categorized into damaged tillers (no panicle initiation), ufraI (panicle completely enclosed in leaf sheath), ufraII (partially emerged panicle but unfilled grain) and ufraIII (completely emerged panicle with unfilled grain) (Cox and Rahman, 1980). Data on damagedtiller (%), ufraI (%), ufraII (%), ufraIII (%), total ufra (%), healthy panicle and yield (t/ha) were recorded after harvesting the crop. A total of 53 rice entries including a resistant and susceptible check were collected from the gene bank of BRRI. Two trials were conducted using the same genotypes in 2 conditions. Pregerminated seeds were sown approximate 0.5 cm deep in each earthen pot (40 cm diameter and 40 cm in height) by using sterilized forceps. The trial was laid out in a completely randomized design (CRD) and each genotype was replicated 3 times in both the ecosystems. A total of 100 seedlings were maintained in each replication for each genotype. Based on the percentage of infection, the test entries were classified into 6 broad groups including highly resistant (0% incidence), resistant (1 to 20% incidence), moderate resistant (21 to 40% incidence), moderate susceptible (41 to 60% incidence), susceptible (61 to 80% incidence) and highly susceptible 81 to 100% incidence (Rahman, 1993; IRRI, 1996). Data on total number of tillers, total number of infested tillers and percentage of infested tillers were recorded at 42 DAS. Benefit cost ratio (BCR) is an important, but underutilized economic analysis tool is the benefit/cost ratio or profitability index. The benefit/cost ratio, B/C or BCR, is the present value of an investment’s benefits divided by the present value of the initial cost. Average profitability analysis of 3 nematicides was done in the onfarm trials of 2 seasons. Statistical analyses were performed by analysis of variance (ANOVA) followed by protected Fisher’s least significance difference (LSD) test at the p_0.05 using CropStats (Gomez and Gomez, 1984).