The inhibitory activity of 37 surface-active agents on the pollen germination of strawberry and camellia has been tested at the concentration of 100 and 10 p.p.m.
The activity was governed by the nature of ionic charge. All cationic agents inhibited the pollen germination and anionic agents showed the inhibitory activity depending on their chemical structure, but nonionic agents had no activity except polyoxyethylene nonylphenol ethers.
The surface-active agents which had the inhibitory activity on the pollen germination tended to cause informal fruits on strawberry. There was a correlation between the inhibitory activity on pollen germination and the phytoxicity on three kinds of plant or the fungitoxicity on Cochliobolus miyabeanus.

View full abstract

The overwintered females of Propylaea japonica THUNBERG were confined in plastic tubes, 3.0 by 8.0 cm, and supplied daily 20 individuals of Nasonovia lactucae. After the larvae of the 3rd generation hatched, these were individually reared with an excess number of various species of aphids daily beyond normal number of consumption at a constant temperature of 25°C, for evaluating the amount of food consumed, duration of larval development, body weight and width of head capsule shortly after emergence. In addition to the growth aspects enumerated above, the nutritional natures of the apterous viviparous females of aphids supplied and those of adult lady-beetles fed on these aphids as food were compared with one another by analyzing the total sugar, water soluble protein and crude lipid. Moreover, the sugar and free amino acid constituents in 5 species of aphids and those in the beetles fed on the same aphids were determined, and at the same time the micromoles of amino acids of 2 species of aphids and adult lady-beetles were carefully measured.
The data compiled in Table 1 show that the food consumption of Propylaea japonica was variable with the different aphid species, and the weight of aphids consumed during total period of development from 1st instar larva to adult tended to increase when the beetles fed on 6 species of aphids, particularly on Dactynotus formosanus and Macrosiphum ibarae. Meanwhile, as might be expected, the duration of larval period of beetles was shortened in agreement with the increase of consumption of favorable foods. Contrary to this indication, the food consumption of beetles extremely decreased with the supply of 4 species of aphids, such as Aphis craccivora pseudoacaciae, Aphis sambuci, Brevicoryne brassicae and Hyalopterus pruni. In this instance the larval period was extended, and also the mortality rate during the course was considerably high. Such a reverse trend of the larval growth in the latter ones was true for the particulars of body weight and width of head capsule.
From Tables 2-3, although a clear-cut tendency of the sugar and protein contents among aphid species could not be pointed out, but in the amount of fat it goes without saying that a much more fat was estimated in the aphid species which were favored by lady-beetles and in their own body fed on these foods. As to the sugar constituents, a similar result was drawn from the data given in Table 4. That is, at least in the favored aphid species more or less a large variety of sugar was detected than in the unfavorable ones. In this case it was confirmed that glucose and fructose appeared to be the principal sugar, though any notice had not been stated in the table.
Further as will be seen in Table 5, although no significant qualitative differences of the free amino acids exist among aphids used, 22-23 amino acids were of general occurrence in the favorable prey as food, in contrast with those of 19-20 varieties in the unfavorable aphids. Quite the same result with above proof was obtained in the free amino acid constituents between the lady-beetles fed on suitable and unsuitable foods. Needless to say, a larger variety of amino acids was detected in the former case, and these must presumably be derived from the foods eaten. In this context, as shown in Table 6, a much higher content of amino acid was evaluated in the suitable prey by the automatic amino acid analyzer, and alanine, glutamic acid and serine were recognized as the main amino acid constituents. Finally it is felt that all of these results concerning the carbohydrate metabolism and nitrogen economy of aphids and their predators may be helpful for future study of the aphidophagous lady-beetles.

View full abstract

In 1959-1961, a variety of rice plant (Norin No.29) was cultivated in different seasons, inoculated with conidial suspension of Gibberella fujikuroi (Saw.) Wall. at each flowering period, and then harvested. The rate of infested seed grains was estimated by means of counting the mycelial growth of Fusarium on nutrient agar medium from surface disinfected grain. It seems that high average temperature and very poor insolation during blossom season increase the percentage of infested seeds.
The preventive effect of 4 sorts of organic mercury compounds on infested seed was examined with various concentrations, temperatures of the solution, and soaking periods. Although there are not any treatments that completely prevent the disease, the soaked seed treatments are more effective than the dry seed treatments. It was considered probable that soaking and presprouting followed on disinfection increase the development of Bakanae disease in nursery, as a results of recovery of the fungi which are incompletely disinfected and remained in the seed grains.

View full abstract

The author carried out experiments on relation between the suspensibility of mixture with pesticides and its spray in jury upon citrus plants. The results of these experiments are as follows;
1. Poor suspensibility was observed on the mixture of Delan (Dithianon) with Supracide (DMTP), Malathon (Malathion) and Azomite (PPPS, Azoxibenzene). These mixture caused remarkable spray in jury upon Satsuma fruit.
2. Poor suspensibility was shown on the mixture of Difolatan with Supracide, Azomite, Galecron (Chlorophenamidine), Malathon, and Kelthane. The mixture of Difolatan with every insecticide caused serious spray in jury upon Satsuma fruit.
3. As to the mixture of Dithane (Zineb) or M-Diphur (Maneb) with insecticide, only the mixture of Dithane with Malathon showed poor suspensibility. No spray in jury, however, were observed on the combinations with these two fungicides and various insecticides tested.
4. Mess cylinders (500ml) of special type (Fig. 1) were used for measuring the suspensibility of mixtures. Standing the mess cylinder containing mixture still for 10 minutes seems to be long enough for measuring the suspensibility of pesticide mixtures.

View full abstract

In southwest Japan, the San Jose scale, Quadraspidiotus pernicious (Comstock), has been abundant on satsuma orange during last several years. Observations on this scale on citrus trees in 1965-71 showed that the insect completed two generations during the growing period and overwintered as third-generation larvae, entering diapause in the latter stage of the first instar. Overwintering larvae continued slowly to develop throughout the cold season to the stage immediately proceeding the first molt and development was then suspended until the temperature reached a suitable level. Therefore, they all molted with a short period of about a week in February or March, though the overwintered larvae are of widely varying ages. Then, the females which hibernated in state of the mature first instar larvae produced the larvae of the 1st generation almost simultaneously with a sharp fluctuation curve at the end of May. The duration from hatching to oviposition was completed its development in the 1st generation in 45-51 days, in 2nd in 43-54 days and in 3rd in 209-272 days, respectively.

View full abstract