Both species belong to the same genus and resemble each other. They migrated and became naturalized to Japan separately 100 and several decades or more ago. Area with dense distribution of Veronica hederaefolia is very limited in contrast to that of V. persica. Reproductive ecology in both species was studied and the relationship between the ecological conditions and distribution was discussed in this paper.
Both species reproduce autogamously (Table 1) and allogamously, and do not produce seeds by parthenogenesis (Table 1).
Some young plants of both species were collected from volunteer communities in Haru and Harada (A and B communities respectively) in Chikushino. The two locations were 8km apart from each other. The A and B plants were grown and selfed seeds “S_A and S_B” were obtained by bagging while open pollinated seeds “Open A” were collected from the A communities. Crossed seeds “F₁ (A×B)” were obtained by artificial crossing in the respective species.
The four kinds of seeds of each species were sown and the growth ability of the plants was compared (Table 2). No significant differences were recognized in the growth rate and seed numbers in the four groups of V. persica plants, whereas in the case of V. hederaefolia the values of these parameters were significantly reduced in the S_A and S_B plants compared with the F₁ (A×B) plants. Inbreeding depression was recognized. This species is considered to show unfavorable characteristics for survival, propagation and colonization when individuals grow in isolation.
Thirty seven species of insects belonging to 3 orders were collected on the flowers of both plant species in the A communities (Table 3).

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According to method of treat with paddy field's herbicide, many giant size formulations are under examination. That new type giant size formulations can throw in the paddies. A purpose of this investigation of giant size formulations is to improve farming difficulties such as the shortage of manpower, etc. Regardless of this, it will anticipate that the giant size formulation do not work properly if algae, duckweed (floating weeds), surface soil separations happen on the surface of rice paddies.
In these studies, the most important problem was to improve the diffusion of Quinoclamine giant tablets that forming agent and 1 piece net 50g (9% a. i.) for 50m². Therefore the field test of diffusion form was investigated in the paddy field division into 50m².
Result of the test was as follows;
1. Diffusion form of Quinoclamine in the water was very high within 24hr after treatment Quinoclamine giant foaming tablet in 50m² paddy field (Fig. 1).
2. In the water, the rises and fall of Quinoclamine concentrations were rapidly than granule formulation (Fig. 5).
3. Disintegration formula of Quinoclamine giant foaming tablet was elucidate for functional formula. These functional formulae showed a change with passage time of Quinoclamine concentration in the water (Fig. 2, 3, 4).
4. Quinoclamine giant foaming tablets were also effective in protecting the environment by it's diffusion foam in the water.

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In the last report, studies were carried out on the methods of application of Quinoclamine giant foaming tablets. As the diffusion form of Quinoclamine in water was very high, Quinoclamine giant foaming tablets were also effective in protecting the environment because the Quinoclamine concentrations decreased rapidly in the water. In this report, the effects of Quinoclamine giant foaming tablets on the control of green algae and surface soil separation were investigated.
Quinoclamine giant foaming tablets effectively controlled surface soil separation as well as some green algae from the early to the middle stages. The effects disappeared after about 3 weeks. In rice injury test, Quinoclamine giant foaming tablets was two times as safe as that of standard treatment (rate of 1kg/10a).
To conclude, Quinoclamine under the formulation of giant foaming tablets could become a suitable algicide affording immediate and effective control of surface soil separation and green algae.

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Selection of soybean (Glycine max L. cv. Enrei) cells tolerant to oxyfluorfen, imazaquin, or fluazifop-P-butyl was attempted using suspension cultures induced from their cotyledons. The concentration required to inhibit the growth of non-selected cells by 50% was 5×10^-8M, 5×10^-7M, and 10^-5M for oxyfluorfen, imazaquin and fluazifop-P-butyl, respectively. By a stepwise selection with increasing concentration, cells tolerant to 10^-7M oxyfluorfen, 5×10^-7M imazaquin, and 5×10^-5M fluazifop-P-butyl, respectively, were obtained. In the selection of imazaquin-and fluazifop-P-butyl-tolerant cells, the tolerance was very slight and the growth of cells was completely stopped when the cells were transferred into 10^-6M imazaquin or 10^-4M fluazifop-P-butyl.
The concentration required to inhibit growth of oxyfluorfen-tolerant cells by 50% was 5×10^-6M, indicating a 100-fold greater tolerance than normal cells. A subsequent study showed that the acquired tolerance was stable for at least 6 months when the cells were retained in the medium without the herbicide.

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The apple snail (Pomacea canaliculata Lamarck) is a pest which attacks newly transplanted rice seedlings, chinese lotus and other aquatic crops.
Experiments were carried out to develop methods of biological weed control using the snail. The results obtained are summarized as follows.
1. The snail fed on various lowland weeds. The snail with a shell 3cm high ate 3g of fresh weeds per day in July.
2. The snail could also eat water grass, Echinochloa oryzicola Vasing until the plants reached the 3-4 leaf age and become 15cm high.
3. Shallow flooding with a water depth of ca. 1cm or drainage management for 15 days after transplanting (until the E. oryzicola plants reached the 3 leaf age) was effective as a physical and cultural method of control to reduce the damage caused by the snails to rice plant.

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Experiments were carried out to analyse the performance, damage to rice seedlings and the weeding effect of the apple snail (Pomacea canaliculata Lamarck), under different methods of water management in paddy fields infested with the snail for several years at depths of 5-6cm from the field surface.
1. The shell height of almost all the snails ranged from 0.8 to 2.7cm in the paddy fields several days after rice transplanting.
Densities of the snail varied from 3 to 7 per m². The snails were distributed uniformly in the paddy fields under a water level of 1-2cm or more in depth.
2. Damage caused by the snails to rice seedlings was negligible when mature seedlings were transplanted and then kept under shallow flooding management for 10 days. When young seedlings were kept under shallow flooding management for 15 days after transplanting, they sustained considerable damage with partial loss of stand in the field under the low water level. However the damage to the seedlings did not result in severe yield reduction due to compensatory effects.
3. Weeding activity of the snails was effective even though standard water management was resumed after surface drainage was applied for 15 days after transplanting.

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Some properties of the tablets of chlornitrofen (CNP) including sodium hydrogencarbonate and tartaric acid as bubbling agents, which are used for weed control in paddy fields were investigated under green house conditions.
The results are summarized as follows.
1. The rate of emission and amount of the bubbling gas increased when the water temperature increased between 10°C and 30°C. At the same time, the amount of chlornitrofen released into water and the herbicidal efficacy on barnyardgrass also increased.
2. The properties of the formulation were affected by the humidity conditions of the tablets during storage. At a higher humidity level, the amount of bubbling gas was smaller than at a lower humidity level. The loss of the bubbling activity resulted in the decrease in the amount of released chlornitrofen and herbicidal efficacy.

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