Efficiency of Garamycin for the Control of Bacterial Disease: Flacherrie in the Larval Instars of Silkworm, Bombyx mori (L) (Race: Double Hybrid)

Abstract

Flacherrie, the bacterial disease is the most significant parameter associated with the loss of silk yield. The loss of appetite; discharge watery feces and vomiting are the common symptoms of infection of bacteria to the larval instars of silkworm, Bombyx mori (L). The present attempt is dealing with utilization of antibiotic compound for the control of bacterial disease: flacherrie in the larval instars of silkworm, Bombyx mori (L) (Race: Bivoltine Double Hybrid). For the bacterial pathogens, the diseased black thorax septicemia infected larvae of silkworm, Bombyx mori (L) were crushed through the use of using mortar and pestle; the solution was filtered; the filtrate was centrifuged (at 4000-5000 rpm) for ten minutes; the precipitate (in the form of pellet) was used for bacterial inoculum. The bacterial sample (inoculum) was streaked in Luria Agar under aseptic conditions and processed for incubation (at 37ºC overnight). After 24 hours, the growth of bacteria was noticed, and it was further processed for sub culture. A bacterial sample was taken through the use of loop; centrifuged for 15 minutes at 4000 rpm and the precipitate (in the form of pellet) was dissolved in distilled water. Soon after the second moult, larval instars were divided into four groups (Untreated control group; Water treated group; Bacterial inoculum treated (infected) group and the group treated with Garamycin antibiotics, each with hundred individuals. The larvae of bacterial inoculum treated (infected) group and the group of larvae for antibiotics treatment were infected (treated) with the aqueous solution of bacterial inoculum. This treatment was carried out through smearing the solution bacterial solution onto the surface of leaves of mulberry, Morus alba (L) (M.5 Variety) leaf surface. The treated leaves were allowed for draining. The treated leaves were fed four times to the third instar larvae on the first day (100 grams of leaves for the group of hundred larvae for each time). For the second day and third day, the larvae were fed with normal untreated mulberry leaves. The water treated group of larvae was fed with mulberry leaves smeared with distilled water. The larvae of untreated control and antibiotics treated group were fed with normal untreated leaves for the days: first, second and third. The antibiotics treatment was followed on the fourth day of the third instar. Hundred grams of mulberry leaves were immersed in four hundred milliliter aqueous solution of Garamycin (40 microgam/ml distal water) for half an hour. The leaves were drained completely. The Garamycin treated leaves were used for the feeding on the fourth day (four feedings at the rate of 100 grams of leaves for the group of hundred larvae for each time). Thereafter, the larvae were fed with untreated mulberry leaves to all the groups of larvae of third, fourth and fifth instars. The haemolymph from the larvae (ten larvae from each group) was collected on the fifth day of the fifth instar and processed for electrophoresis. The hundred percent effective rate of rearing (ERR) were reported for the Garamycin treated group. Single female cocoon weight: 1.564 (±0.429) units with the shell ratio: 24.744 units and single male cocoon weight: 1.193 (±0.055) with the shell ratio: 22.967 units were reported for the Garamycin treated group. The variation was detected in the pattern of banding of the protein with significant polymorphism (88.3 percent) with two bands of monomorphic nature; twelve bands of polymorphic nature and three bands of “unique” nature.