to compare the performance of fifteen hybrids of silkworm, bombyx mori l. under natural rearing conditions on the farm level and determine their resistance to grasserie disease, an experiment was conducted in a completely randomized design (15 treatments and five replications) for either of non-infected or infected to npv conditions. treatments included hybrids xinhang1?koming1, xinhang1?koming...

We examined seasonal changes in freeze tolerance and the susceptibility of larvae of the gall fly, Eurosta solidaginis to inoculative freezing within the goldenrod gall (Solidago sp.). In late September, when the water content of the galls was high (approximately 55%), more than half of the larvae froze within their galls when held at -2.5 degrees C for 24 h, and nearly all larvae froze at -4 o...

Soybean-cyst nematode larvae survived in water up to 630 days, depending on incubation temperature. Most larvae were killed when ice crystals formed in water, and all died after 1 day at 40 C. At temperatures of 0, 4, 8 and 12 C, larvae survived for the duration of the experiments (630 days). From 16 to 36 C, survival was inversely correlated with temperature. In naturally infested soil, nemato...

The effects of stocking density of eggs and larvae were studied related to the morphological deformities appearance, percentage of survival, and growth rate, in order to achieve the most suitable stocking density for eggs and larvae in incubators and rearing tanks. The egg stocking densities were 500, 700 and 900 g per incubator for great sturgeon, 500 and 1000g per incubator for Persian sturge...

The relationship between growth rate, rate of morphological development, and length of larval life, was examined for larvae of the blue mussel Mvtilus edulir L. The larvae were reared at phytoplankton (Isochrysis galbana, clone T-ISO) concentrations between 0.5 x 10“ and 30 x 104 cells. ml’ at either 12 or 16 “C. Growth rates generally increased with increasing food concentration and were highe...

Yolk-sac fry of Goldfish (Carassius auratus gibelio) were exposed to various concentrations of Al and pH for 3, 7 and 10 days. In this study number of dead fish, total length of larvae, yolk sac length, swimming activity, the number of gill cover movements and the number of heart beat was measured. The lowest and highest number of gill cover movements belong to the waters containing 50 mg L-1 o...

The lady beetle, Curinus coeruleus (Mulsant), a biological control agent of the coconut mealybug, Nipaecoccus nipae (Maskell) and the psyllid, Heteropsylla cubana Crawford, was examined for its ability to consume Aedes albopictus (Skuse) eggs in the laboratory. Most C. coeruleus larvae in this test preyed on A. albopictus eggs (75% for the 2 and 3 instar and 71% for the 4 instar). The 2 and 3 i...

Introduction: The mosquito species of Ae. aegypti is a vector arthropod-borne diseases such as dengue haemorrhagic fever. Acetylcholinesterase (AChE) enzyme in that encoded by the ace-1 gene. Damage gene target insecticide lead to loss normal structure and function AChE. However, damage remains uncharacterised. main aim this study was find out point mutations larvae treated with methanolic extr...

Fleas Xenopsylla conformis mycerini and Xenopsylla ramesis replace each other on the same rodent host (Meriones crassus) in two habitats that differ in substrate texture (sand and loess-like sediments, respectively). We hypothesized that the substrate is an important factor determining flea distribution and studied survival of larvae, pupae and newly emerged adults as well as the rate of pre-im...

The effects of stocking density of eggs and larvae were studied related to the morphological deformities appearance, percentage of survival, and growth rate, in order to achieve the most suitable stocking density for eggs and larvae in incubators and rearing tanks. The egg stocking densities were 500, 700 and 900 g per incubator for great sturgeon, 500 and 1000g per incubator for Persian sturge...