Abstract
(1) Effects of I. P. C., a chemical herbicider of graminous weeds, have been tested since the spring in 1949. (2) Although the tests were ended in failure frequently at summer season. In October when seedling of onion, spinach and graminious weeds grew up about 3∼7 cm in height, water solution ot 0.67% I.P.C. at the rate of 15∼22.5 liter per are (100∼200g of I.P.C. was used per are) were sprayed over the field. It was proved that this water solution was so effective a selective weed killer that raminous weed were all killed ter solution was so effective a selective weed killer that raminous weed were all killed within 2∼3 days without damage to seedlings of onion and spinach, and no weeds grew there after. (3) However, oil solution of 4% I.P.C. at the rate of 0.75∼1.5 liters per are (30∼60 g of I.P.C. was not only weeds but also the crop all together, therefore oil solution of of I. P. C. was not recognized to act selectively. (4) It is noted also that the effect of I.P.C. is not remarkable for the grown up graminous plants. (5) On November 18th, immediately after the seeds of pea, broad beans, rape, wheat and barley were sown, 100∼150 g of I.P.C. water emulsion and 30∼60 g of I.P.C. oil solution per are were sprayed over the field. (6) In this series of experiments, it was found that in plot where more than 60 g of I.P.C. was used, no weed was seen for 40 days and after 135 days, the quantity of weeds was only 1/5∼1/(50) as compared with that of the untreated plot. There was no damage on the germination and the growth of pea, broad bean and rape, while barley and wheat grew very sparsely. (7) It was concluded from the results that I.P.C. was a effective weeder acting selectively on the Graminious plants only. It was also noted that pretreatment of soil with I.P.C. was most effective and its application to young weeds also gave considerably good results.
