Population abundance of red spider mite, Tetranychus urticae Koch., was studied in cucmber, ribbed gourd, bitter gourd, snake gourd, aroids and teasle gourd and efficacy of four new acaricides were tested against this pest in brinjal at the farmer's field of Norsingdi during 2009-2010. At the same time, the spatial distribution of this pest in brinjal crop was also studied. Results indicated that all the surveyed vegetables except bitter gourd were attacked by the mite with varying levels of infestation. However, the highest mite population per leaf was observed in brinjal (32.27) which was followed by cucumber (16.08) and teasle gourd (7.2). Mites were most densely populated in the lower canopy region in the brinjal plant. Among the tested acaricides, Lakad 1.8 EC (Abamectin) provided the highest (83.4%) reduction of mite population over control, although the other acaricides also gave good control of this pest.

Four botanicals viz., mahogany oil, mahogany seed extract, tobacco leaf extract, neem seed kernel extract along with one synthetic chemical, cypermethrin were tested for their efficacies against H. armigera. The lowest fruit infestation, both by number and weight, was observed in neem seed kernel extract (27.15%, 22.29%) treated plot which was statistically similar to tobacco leaf extract (27.71%, 23.31%) treated plot and cypermethrin (28.87%, 25.44%) treated fruits. While no significant difference was found among mahogany oil, mahogany seed extract and control treatments. Percent infestation reduction over control was the highest in neem seed kernel extract (30.08%) followed by tobacco leaf extract (28.68%). The highest yield (18.14 t/ha) and the highest MBCR (2.99) were also obtained from neem seed kernel extract treated fruits.

Field studies were carried out to evaluate the efficacy of four new generation insecticides along with a botanical against mustard aphid (Lipaphis erysimi Kalt.) and their toxicity to coccinellid beetles and foraging honeybees during 2014-15 at Bangladesh Agricultural Research Institute (BARI), Gazipur, Bangladesh. Buprofezin 40 SC was found to be the most effective against aphid offering the lowest aphid population (1.56/ top10cm central twig) at 7 days after spraying (DAS) which was statistically identical to Diafenthiuron 500SC (1.85/ top10cm central twig). Among the treatments, Azadiractin 1EC appeared to be safest to coccinellid beetles and foraging honeybees because it recorded the highest number of beetle (7.50 /5 plants) and honeybee (9.64 /plot/5 min) population at 7 DAS, although honeybee population did not vary statistically with that of Buprofezin 40 SC and Lufenuron 5EC treated plots. Indoxacarb 145SC was found to be the most toxic against honeybees. However, the highest yield was obtained from Buprofezin 40 SC (1.57 t ha -1 ) treated plot although this was statistically identical to that Diafenthiuron 500SC (1.52 t ha -1 ) and Azadiractin 1EC (1.48 t ha -1 ) treated plots.

This study evaluated the field efficacy of three newly introduced synthetic insecticides namely, Python 20SL (Nitenpyrum), Plenum 50WG (Pymetrozin), Polo 500SL (Diafentiuron) along with commonly used chemical Admire 200SL(Imidacloprid) against sucking insects of eggplant such as aphid, jassid, white fly and thrips. The effect of the insecticides on the population reduction of the novel predator lady bird beetle was also studied. Among the chemicals, Polo 500SC was found to be the most effective followed by Plenum 50WG against the sucking insects by reducing significant percentages of their population at 3 and 7 days after spray. Polo 500SC and Plenum 50WG were found to be the least deleterious against lady bird beetle since it caused lowest population reduction. Considering the higher percentages of population reduction of the pests and significantly lower affect on the predator, Polo 500SC and Plenum 50WG may be considered as a tool of IPM for management of sucking insects in the eggplant field.

The experiment was conducted at the experimental field of Entomology Division, BARI, Gazipur during Rabi 2007-08. Two microbial insecticides HaNPV @ 0.4ml/L and Bt @ 2g/L along with their combination were tested against H. armigera. The lowest fruit infestation, both in number and weight, was obtained from treatment HaNPV and Bt alternate spraying (11.78%, 9.64%), followed by Bt (13.25%, 10.85%) and HaNPV (17.67%, 13.11%). The highest fruit yield (16.92 t/ha) was obtained from HaNPV and Bt alternate spraying plots followed by Bt (16.65 t/ha) and HaNPV (14.73 t/ha). In case of MBCR, the highest MBCR was obtained from HaNPV and Bt alternate spraying (5.30) followed by HaNPV (4.46) and Bt (3.37). DOI: http://dx.doi.org/10.3329/agric.v12i1.19583 The Agriculturists 2014; 12(1) 68-74