Md. Saiful Islam
Department of Entomology, Bangladesh Agricultural University, Mymensingh-2202, Bangladeshand International Rice Research Institute, Bangladesh Office, Banani, Dhaka-1213, Bangladesh
Chandra Kanta Dash
Department of Entomology, Sylhet Agricultural University, Sylhet-3100, Bangladesh
Md. Fuad Mondal
Department of Entomology, Sylhet Agricultural University, Sylhet-3100, Bangladesh
Kazi Shahanara Ahmed
Department of Entomology, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh
Md. Azizul Haque
Department of Entomology, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh
Spices, Grain Protectant, Pulse Beetle, Gram Seed
Department of Entomology, Bangladesh Agricultural University, Mymensingh.
Pest Management
Insect Culture
Pulse beetles, Callosobruchus chinensis (L.) were reared by maintaining insects on gram seeds at room condition (average temperature 27?C and average relative humidity 70%) in the Department of Entomology, Bangladesh Agricultural University, Mymensingh. Fifty pairs of adult male and female pulse beetles were placed in glass jar containing gram seeds. The jar was then covered with black cotton cloth and the beetles were allowed for free mating and oviposition for 7 days in the aforementioned environmental conditions in a dark place. The parent beetles were removed and pulses containing eggs were kept in a jar for further development and getting new adults. Rearing of the insects was continued for the whole experimental period.
Plant Materials
Four spices namely, Black pepper (Piper nigrum L.), Black cumin (Nigella sativa L.), Methi (Trigonella foenum-graecum) and Garlic (Allium sativum L.) were assessed for their insecticidal potency against pulse beetle. They were collected from the local market of Mymensingh, Bangladesh. The collected test materials were dried in oven at 600 C for three to four days until they were reached constant weight and ready for powder preparation. Spice powders were prepared by pulverizing the oven dried seeds/cloves with the help of a steel blender. Then the dust was passed through a 25-diameter sieve to obtain fine and uniform powder.
Sampling of Gram Seeds
Gram (Cicer arietinum) Seeds were used in this experiment as host of pulse beetle and were collected from local market of Mymensingh. The seeds were completely free from insects and microorganisms. There were no other crop seeds and foreign materials in the seed lot. No insecticide was used on the gram seeds in the storage and before storing seeds was properly dried.
Insect Bioassay
Experiments were carried out in the laboratory of Entomology Department in Bangladesh Agricultural University. The spice powders were mixed with the gram seeds (20 g) @ 1.00, 0.50 and 0.25 g/kg gram seeds in separate petridishes (90 mm in diameter). Five pairs of newly emerged adult beetles were released into each Petridish containing treated seeds. Three replications were made for each treatment with control. The petridishes were kept in the in the room temperature without any disturbance. The efficacy of spice powders against pulse beetle was evaluated considering parental mortality, number of eggs, adult emergence and seed weight loss from treated and untreated seeds. Data on the parental mortality was recorded daily from 1st day to 7th day of release of the pulse beetles. After seven days total number of dead beetles were calculated
Mortality=(Total number of dead pulse beetle/Total number of pulse beetle released)×100
After seven days seeds were carefully examined using magnifying glass and seeds with eggs or without eggs were separated. After separation total number of egg bearing seeds and total number of eggs were recorded. After hatching the larvae of the beetle entered in the seeds and fed on the cotyledon where they pupate and came out as adult by making holes on the seed coat. The number of adult beetle emerged were counted daily from the date of first emergence and continued till last emergence. The pulse beetle started emerging after 24 days of release. Weight loss of pulse seeds caused by the feeding of pulse beetle was determined. The seeds were separated from dust and dead bodies of pulse beetle by winnowing. The clean seeds in each petridish were separately weighted. The weight loss of pulse seed was calculated by subtracting the final weight from initial weight. Then the weight loss was converted into percentage by the following formula:
Seed weight loss (%) = (A−B/A) ×100
Where, A=Initial weight; B=Final weight.
Statistical Analysis
Data obtained were statistically analyzed in accordance with two factors Completely Randomized Design (CRD) and treatment means were compared by Duncan's Multiple Range Test (DMRT).
Universal Journal of Plant Science 1(4): 132-136, 2013
Journal