Whitefly (Bemisia tabaci) is the vector of tomato yellow leaf curl virus (TYLCV), is a serious pest of vegetables and other crops worldwide. The experiment was conducted at Bangladesh Agricultural Research institute (BARI) during two consecutive years of 2009 and 2010 to select a suitable bio-rational management practice against white fly, transmitting TYLCV. Treatments comprising tomato variety Ratan with diseased plant uprooting, spraying admire, applying admire on trap crop (marigold), spraying neem, sesame and mustard oil with trix and the untreated control were used in this experiment. The variety Opurba with similar materials as described above was used. Percent virus infected tomato plants ranged from 1.33 to 19.00 in two consecutive years, where the highest infection was recorded in control plot with variety Opurba and the lowest was recorded in variety Ratan treated with Admire. Consequently, the highest yield (47.70 and 52.36 t ha -1 in 1 st and 2 nd year, respectively) in the plots of variety Ratan treated with admire and the lowest yield was recorded in untreated control plots with variety Opurba (14.75 and 30.30 t ha -1 ) for the two consecutive years. A strong positive correlation was observed between whitefly population and % TYLCV infection for both the years and both varieties of tomato. While a negative correlation was observed between % TYLCV infection with number of fruits plants -1 and yield (t ha -1 ) for both the years and in both varieties of tomato. These results are consistent with the occurrences of TYLCV, which have been associated with the percent virus infection in relation to yield and yield contributing characters of tomato.

Wheat seed samples were collected from ten unions of sadar upazilla of Thakurgaon district in wheat growing season of 2011. Seeds were tested by blotter method at Seed Pathology Center (SPC), Bangladesh Agricultural University, Mymensingh during the months April to November 2011 for recording and identifying the seed-borne fungi associated with wheat seeds. The health status of 20 seed samples were determined whereas five genera fungi were identified from a total of six fungus. The fungi were Bipolaris sorokiniana, Alternaria tenuis, Fusarium spp, Penicillium sp, Aspergillus flavus and Aspergillus niger. Prevalence of the total as well as the individual seed-borne fungal infections that were recorded varied significantly with respect to wheat varieties and sources of seed collection. Seed samples collected from Jagonathpur and Gorea unions of sadar upazilla showed highest percentage of seed-borne infection compared to the samples collection from other unions for both varieties. The seed-borne fungal infection in Hazar-8 and Satabdi collected from other unions showed lowest percentage of seed-borne fungal infection than that of Jagonathpur and Gorea unions. Seed germination also varied significantly depending on the varieties and the seed sources and a positive correlation between seed germination and seed-borne fungal infections were observed. Three seed treating agents viz., neem leaf extract 1:2, hot water and Provax were evaluated for controlling seed-borne fungi associated with wheat seeds. Among the seed treating agents, Provax was found superior to reduce the seed-borne infection of wheat. The results also showed that neem leaf extract at 1:2 dilutions was observed to be the most effective in reducing seed-borne fungi with highest percentage of germination followed by hot water treatment.