In this paper the relationship between the volume of diluting water for spraying and the controlling effects of some fungicides against bentgrass brown patch caused byRhizoctonia solaniKühn was studied and the permeability of used fungicides throughZoysiaturfgrass layer was discussed. The experimental results obtained in this work are summarized as follows.
1. When Captan 2g/m², Thiram 2g/m² and TPN 1.6g/m² were diluted with 0.1, 0.5, 1.0, 2, 0 and 4.0l/m² water the controlling effects were low in the case of less volume of diluting water, and TPN gave lower effect in the case of more diluted solution. Thiophanate methyl 0.8g/m²and SKKF-1 2g/m², however, gave constantly high controlling effect in spite of volume of diluting water.
2. After Captan 2g/m², Thiram 2g/m², TPN 2g/m² and SKKF-1 2g/m² were diluted with 1.0, 0.5 and 0.1l/m² water respectively and sprayed to turfgrass, waterings of 0.5 and 0.9l/m²immediate and nextday after spraying indicated ineffective result on Captan, Thiram and TPN which were diluted with 0.9l/m²water but effective with 0.5l/m²and without dilution. SKKF-1 showed effective control in .spite of watering.
3. When captan 2g/m² diluted with 1-8l/m² water was applied to turfgrass layer, the more volume of diluting water is used observed, the higher permeability of fungicideis.
4. After Captan 2g/m²was applicated with dilution with 0.5l/m²water to turfgrass layer, waterings by both 4 and 8l/m²immediate and next day after application did not accerelate the permeability of applicants.
5. To compare the permeability of several fungicides diluted with 4l/m²through tnrfgrass layer, Captan 2g/m², Thiram 2g/m², TPN 2g/m²and SKKF-1 2g/m²were sprayed. The former three fungicides showed less permeability but the later one did high.
6. In case of addition of 500 to 1000 fold dilution of spreader to diluting water, the effective control was obtained in application of Captan 2g/m²diluted with 1l/m²water. It is suggested that the addition of spreader to applicants resulted more effective control on turfgrass brown patch.

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The authors investigated the life history and seasonal prevalence of theGeoblissus hirtulusBurmeister, as well as damage to turfgrass grounds in golf courses built on the sand hill, during the period from November, 1977 through December, 1978. The results are summarized as follows:
1. The damage to turfgrass by this insect occurs on the slopes facing to the south in the sand or sandy soil area. First, due to the underground part of turfgrass sapped by this insect, the stems and leaves on the ground wither, and subsequently the subterranean stems are exposed in the form of fiber by an outflow of soil. Such damage continues from the latter part of August to next May, with progressive spread of the damaged area.
2. Adults were distinguished into male and female according to shape of the genital segment in their abdomen. In this experiment, the average number of eggs laid is 4.1. This would be because the adults that oviposit in Petri dishes are short-lived. The length of the oviposition period is 4.5 days.
3. Eggs average 0.92 mm in longer diameter and 0.45 mm in shorter one, and no absorptive growth is observed. The lengths of egg stage at 20°C, 25°C, and room temperature are 30.5, 17.6 and 18.4 days, respectively, with the good percentage of egg hatch.
4. During the period of larval hatch continuing from June to September, the larvae grow gradually and molt five times. New adults emerge in and after August. Almost all adults winter except some cases of wintering at the larval stage. It is generally supposed that the adults after wintering begin to oviposite in the middle part of next May.

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In order to select the effective insecticides for control ofGeoblissus hirtulusBurmeister injurious to turfgrass, the insecticidal effect of 15 insecticides was evaluated by laboratory and field tests.
a. From the results of insecticidal tests on adults of this insect by the impregnated filter paper method, cartap showed the greatest effect, followed by salithion, r-BHC, PHC, fenitrothion, fenthion, diazinon, CVP in that order.
b. Concerning the rate of penetration of several insecticides into the soil of sample pots, the liquid form showed higher penetration into the soil than the granular form.
Then, in test data for several liquid formulations, PHC showed the highest soil penetration.
Secondary fenthion showed the higher penetration and cartap showed the lowest.
Further, for penetration of several granule-type formulations into soil owing to differences in the number of waterings, only PHC penetrated to the B soil layer after four waterings. Fenthion and diazinon did not penetrate to the B layer even when the number of waterings increased.
c. Compared with the persistent effect against adults of this insect when 6 insecticides diluted to 1/1000 were sprayed at 41/m²over the turfgrass area, PHC (50% W. P.) showed more thans 30% mortality on the 15th day after spraying. Other insecticides showed less than 30% mortality on the 5th day.
d. It seems to me that control of this insect by pesticides is in the period from the middle of May to early June, because, the peak of adult emergence is the highest in this season and the adults live in shallower soil.
We suggest that PHC (50% W. P.) or fenitrothion (50% E. C.) diluted to 1/1000 be sprayed with the above 41/m²over the involved turfgrass area.

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In northern part of Kanto district, dallisgrass, which is a perenial grass, germinates from seed or rhizome between late April and early May, 20 to 30 days later than Japanese lowngrass and Manila grass, grows vigorously in relatively high and high temperature condition, and endures in wide range of soil pH and humidity. The plant in turf tolerates traffic pressure or cutting, and is hard to control by usual herbicides. The seeds have dormancy which is caused by the water impermeability of seed coat, and the dormancy is broken by humidity and low temperature.
The plant is tolerant to the preemergence treatment of usual herbicides, but can be controlled by relatively high rate of atrazine, triclopyr, cremart, etc. The plant of three to four leaves can be controlled by the foliage treatment of atrazine, DSCP (DSMA+MCPP), triclopyr and so on. The dallisgrass which germinated from rhizome can be controlled by the early treatment of atrazine or by the combination of atrazine, asulam, triclopyr or DSCP and cutting of foliage after a week or so.

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The tests and applications of herbicides CAT (2-chloro-4, 6-bis (ethylamino) -striazine) and Atrazine (2-chloro-4-ethylamino-6-isopro-pylamino-1, 3, 5, -triazine) to tnrfgrass have been carried out for years.
The mixture of CAT and Atrazine clearly showed remarkable effectiviness and similar synergistic action to perennial weed (Oxalis corniculata L.) . No injury was given to turf-grass (Zoysia matrella M.) in greenhouse test. Also in field test, both herbicidal activity and selectivity were excellent as same as in greenhouse test.
In conclusion, it was considered that the mixture of CAT and Atrazine can apply excellently to tnrfgrass.

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We made an experiment on the penetration through soil of insecticides making injurious insects of turfgrasses, especially white grubs, an object of pest control.
1) When we made the second-stage grubs an object, both of MEP and EPN were effective from soil surface to a depth of 4cm, but not effective below a depth of 4cm. When we made the third-stage grubs an object, they were effective from soil surface to a depth of only 2cm. But we addedpenetration adjuvants of anion system, the mortality of insects a little increased in the soil layer from a depth of 2cm. to 4cm. We think this is because the penetration adjuvants let the systemic action increase below a depth of 2cm.
2) When we measured the amount of the insecticides in soil by the gaschromatograph, in spite of the high volume spray of 4lit/m², the active ingredient remained in the soil layer from soil surface to a depth of 2cm. In sand soil, 97% of the all amount of the detected insecticides remained from soil surface to a depth of 2cm. In Kuroboku soil, 99% remained there. The concentration of the insecticides was less than 2ppm. in the soil layer from a depth of 2cm. to 4cm. By 1 lit, spray, which is a practical application rate, 99.9% remained from soil surface to a depth of 2cm.
When we make such injurious insects in soil as white grubs an object of pest control, it is important how deep we can make insecticides penetrate through soil. We are now studying penetration adjuvants and the suitable time for the application of insecticides.

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[in Japanese]

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