The EAG (Electroantennogram) has been used to find out chemical substance effective to insect. We tried to use EAG recording for catching of responsible acoustic signals to Lirimyza trifolii (Diptera: Agromizidae). In fly auditory organ known as Johnston's organ located on antenna. Pure tone sounds (sine wave) and courtship songs of several kinds of species were broadcasted to excised head of the fly. Significant EAG signals were detected when released the 20 Hz pure tone sound and long pulse train patterns, which were courtship songs of Cryptonevra inquilina and Lipara japonica (Chloropidae). For conformation of it's effectiveness, we further analyzed movement behavior with the signal got from the EAG recording. Information entropy could represent the specimens activities of movement tracks. The entropy with sound was relatively lower than without sound. The combination of EAG responding and behavioral observation would be useful to analyze the response of insect pest against acoustic signals and develop acoustic pest managing tool in agriculture.

We have analyzed vector magnetograms and Hβ filtergrams of two sunspot groups, one in a growing phase and the other in a decaying phase. In this study, the temporal evolution of their magnetic morphology has been investigated in association with solar activity. The morphological variations of the growing and decaying phase of these sunspots revealed in detail the coalescence of small spots into a large spot and the fragmentation of a large spot into many small spots, respectively. Numerous small flares were detected in the spot group during the decaying phase. This seems to be intimately associated with the shearing motions of many spots with different polarities created by fragmentation of a large sunspot. The magnetic flux and the average shear angle are found to be substantially reduced during the decaying phase, especially in the course of the flarings. This implies that the decaying phase of the sunspot is, to some degree, involved with magnetic field cancellation. The growing spot group has not shown any large activities, but numerous small spots have grown into a typical bipolar sunspot.

Two unrecorded alien plants, Melilotus officinalis (L.) Lam. and M. indicus (L.) All. (Leguminosae) were found in Korea. M. officinalis is native to Eurasia and widely distributed in agricultural regions throughout the world. M. indicus is native to Mediterranean and Southwestern Europe, and naturalized in temperate regions all over the world. These species are morphologically similar to M. suaveolens (Jeon-dong-ssa-ri). However, M. officinalis is distinguished from M. suaveolens by transverse nerved legumes, definite ovary stalks, and five to eight number of ovules in ovary. M. indicus is also distinguished from M. suaveolens by smaller size of flowers, broadly triangular calyx teeth, globose legumes, and minutely papillose seeds. The local name of M. officinalis and M. indicus were given as “Ju-reumjeon- dong-ssa-ri” and “Jom-jeon-dong-ssa-ri” based on transverse nerved legumes and overall smaller size than M. suaveolens, respectively. The descriptions on morphological characters and photographs at the habitat of M. officinalis and M. indicus are provided.

To study the effects of an urease inhibitor, N-(n-butyl)-thiophosphoric triamide (NBPT), and a nitrification inhibitor, dicyandiamide (DCD), on nitrogen losses and nitrogen use efficiency, urea fertilizer with or without inhibitors and slowrelease fertilizer (synthetic thermoplastic resins coated urea) were applied to direct-seeded flooded rice fields in 1998. In the urea and the urea+DCD treatments, NH4 + -N concentrations reached 50 mg N L-1 after application. Urea+NBPT and urea+ NBPT+DCD treatments maintained NH4 + -N concentrations below 10 mg N L-1 in the floodwater, while the slow-release fertilizer application maintained the lowest concentration of NH4 + -N in floodwater. The ammonia losses of urea+NBPT and urea+NBPT+DCD treatments were lower than those of urea and urea+DCD treatments during the 30 days after fertilizer application. It was found that N loss due to ammonia volatilization was minimized in the treatments of NBPT with urea and the slow-release fertilizer. The volatile loss of urea+DCD treatment was not significantly different from that of urea surface application. It was found that NBPT delayed urea hydrolysis and then decreased losses due to ammonia volatilization. DCD, a nitrification inhibitor, had no significant effect on ammonia loss under flooded conditions. The slow-release fertilizer application reduced ammonia volatilization loss most effectively. As N03 [-10] -N concentrations in the soil water indicated that leaching losses of N were negligible, DCD was not effective in inhibiting nitrification in the flooded soil. The amount of N in plants was especially low in the slow-release fertilizer treatment during the early growth stage for 15 days after fertilization. The amount of N in the rice plants, however, was higher in the slow-release fertilizer treatment than in other treatments at harvest. Grain yields in the treatments of slow-release fertilizer, urea+NBPT+ DCD and urea+NBPT were significantly higher than those in the treatments of urea and urea+DCD. NBPT treatment with urea and the slow-release fertilizer application were effective in both reducing nitrogen losses and increasing grain yield by improving N use efficiency in direct-seeded flooded rice field.field.