Colonization and Intrusive Invasion of Potato Psyllid by ‘Candidatus Liberibacter solanacearum’

Previous studies have shown that the fastidious bacterial plant pathogen ‘Candidatus Liberibacter solanacearum’ (CLso) is transmitted circulatively and propagatively by the potato psyllid (PoP) Bactericera cockerelli. In this study, the temporal and spatial interrelationships between CLso PoP were investigated by scanning electron microscopy of the digestive system of PoP immature and adult instars and salivary glands of adults post CLso ingestion. CLso biofilms were not detectable on the outer midgut surface of the first and second instars; however, for third to fifth instars and teneral and mature adults, biofilms were observed in increasing numbers in each successive developmental stage. In adult PoP midguts, CLso cells were observed between the basal lamina and basal epithelial cell membranes; in basal laminar perforations, on the outer basal laminar surface, and in the ventricular lumen, epithelial cytosol, and filter chamber periventricular space. CLso were also abundantly visible in the salivary gland pericellular spaces and in the epidermal cell cytosol of the head. Collectively, these results point to an intrusive, systemic invasion of PoP by CLso that employs an endo/exocytosis-like mechanism, in the context of a propagative, circulative mode of transmission.

Comparison of rainfall and water requirement for rice during rice growing period in Kirtipur, Nepal

An experiment was conducted to estimate the crop water requirement of rice and to compare it with the amount of rainfall. Experiment was designed to estimate evaporation and evapotranspiration in cylindrical half cut mineral water bottles. Rice was planted in the bottles to estimate evapotranspiration. The amount of rainfall during the experiment period was recorded in the rain gauge station. The evaporation was highest in the month of September (3.16 mm/day) and lowest in June (2.56 mm/day). The rate of evapotranspiration was in increasing order from June to September ranging from 3.43 mm/day in June to 19.57 mm/day for September. The crop water requirement was in increasing order reflecting more water demand with the increase in days after plantation and successive developmental stage of rice. The total amount of rainfall in the study area over study period (23rd June to 30th September, 2005) was 549.59 mm. The total crop water requirement of rice for same period in the same area was 711.45 mm. It showed that the rainfall during the study period was insufficient to meet the water demand for rice in the study area.

Rainfall And Water Requirement Of Rice During Growing Period

An experiment was conducted to estimate the crop water requirement of rice and to compare it with the amount of rainfall. Experiment was designed to estimate evaporation and evapotranspiration in cylindrical half cut mineral water bottles. Rice was planted in the bottles to estimate evapotranspiration. The amount of rainfall during the experiment period was recorded in the rain gauge station. The evaporation was highest in the month of September (3.16mm/day) and lowest in June (2.56mm/day). The rate of evapotranspiration was in increasing order from June to September ranging from 3.43 mm/day in June to 19.57mm/day for September respectively. The crop water required was in increasing order reflecting more water required with the increase in days after plantation and successive developmental stage of rice. The total amount of rainfall in the study area over study period (23rd June, to 30th September, 2005) was 549.59mm. The total crop water requirement of rice for same period in the same area was 711.45mm. It showed that the rainfall during the study period was insufficient to meet the water demand for rice in the study area. The Journal of Agriculture and Environment Vol:13, Jun.2012, Page 1-4 DOI: http://dx.doi.org/10.3126/aej.v13i0.7576