Weeding techniques in transplanted and direct wet-seeded rice in Pakistan

Field studies were undertaken to explore the weed management strategies for transplanted and direct wet-seeded rice in the Dera Ismail Khan district of North-west Frontier Province, Pakistan. The experimental design was a randomized complete block with a split plot arrangement. The main plots consisted of two planting techniques (transplantation and direct seeding), while weed control practises assigned to the subplots included the use of the granular herbicide Sunstar 15WG (ethoxy sulfuron), Machete 60EC (butachlor), conventional hand weeding, and the weedy check (untreated control). Data were recorded on weed dynamics and the agronomic parameters of the rice crop. Economic analyses on the data were also run. The weed density and biomass were lower in the transplantation plots than the direct-seeding plots. The herbicides ethoxy sulfuron and butachlor reduced the density over the weedy check, with a density comparable to hand weeding in 2002, but slightly higher in 2003. As a result of weed management by hand weeding and herbicides, the paddy yield and its components were significantly higher for the transplanted method compared to the direct-seeded method. The comparable yield of herbicides with hand weeding offers an option for the use of herbicides as an alternative management tool. In light of our findings, it is concluded that for good economic returns, rice crops may be transplanted rather than direct-seeded. The herbicides ethoxy sulfuron and butachlor offer a weed control cover comparable with hand weeding under the transplantation method, while butachlor is good for controlling weeds even under the direct-seeded conditions in the agroclimatic conditions of the area.     

Studies on herbicidal carbamoyltetrazolinone derivatives: Selection of fentrazamide

1-Phenyl-5(4 H )-4-dialkylcarbamoyltetrazolinones represent a new class of herbicides that are active against barnyardgrass ( Echinochloa spp.) in paddy fields. To select the most favorable compound as a paddy herbicide, herbicidal activity and selectivity of the carbamoyltetrazolinone compounds to transplanted rice were determined in greenhouse tests. Higher herbicidal activities were associated with the compounds having a 2-Cl- or 2-Cl-6-Me-substituted or an unsubstituted phenyl ring, and a combination of C_2–3 linear alkyl group and a C₄ branched-chain alkyl or a C_5–6 cycloalkyl group on the nitrogen atom in the carbamoyl structure. In addition, the compounds carrying a total of seven to nine carbon atoms in the substituents on the carbamoyl nitrogen exhibited a good selectivity between barnyardgrass and transplanted rice plants. From the results of soil thick-layer chromatography, the good crop compatibility of carbamoyltetrazolinones was correlated to the mobility of the compounds in paddy soil. The investigation resulted in the selection of an excellent compound, 4-(2-chlorophenyl)- N -cyclohexyl- N -ethyl-4,5-dihydro-5-oxo-1 H -tetrazole-1-carboxamide (common name: fentrazamide), as a rice paddy herbicide for controlling barnyardgrass.     

Recruitment strategy of swimming crab, Portunus trituberculatus, in Hiuchi-Nada, Japan

The recruitment strategy of swimming crabs, Portunus trituberculatus, was investigated by field observations and numerical experiments in Hiuchi-Nada, Japan. Calculated dispersal patterns of zoeal and megalopal stages in a three-dimensional numerical model reproduce observed patterns accurately. The temporal change of vertical migration patterns between the 1st and 2nd zoeas and the 3rd and 4th zoeas plays an important role in the process of recruitment of P. trituberculatus from spawning ground to nursery ground.     

First detection of adiaspiromycosis in the lungs of a deer

Adiaspiromycosis is a pulmonary infection caused by the soil fungi, Emmonsia crescens and E. parva. It primarily affects small mammals and can range from an asymptomatic condition to fatal disseminated disease. We detected a granuloma containing fungal spherules, which were morphologically consistent with the adiaspores of E. crescens in the lungs of a female Hokkaido sika deer. This is the first reported case of adiaspiromycosis involving a cervid in the world.