INSECTS INJURIOUS TO AGRICULTURE IN JAPAN 67 



and hatch the following month. The winter is passed in the larval 

 stage. 



The tenebrionid Gonocephalum (Opatrvm) reticulatum (7) causes 

 more or less injury in Chosen by the feeding of the adults upon 

 the 3 7 oung foliage and of the larvae upon the roots. There is one 

 brood each year, and the winter is passed in the larval stage in the 

 soil, the adults appearing late in April. It attacks also ginseng and 

 •burdock. 



The anthomyiid leaf miner Pegomyia vioina (7) is common in 

 Chosen and at times becomes abundant. There are three broods a 

 year, the adults of which appear in early June, the middle of July, 

 and late August. The winter is passed in the pupal stage in the soil. 

 The eggs are laid in groups of three or four on the lower surface of 

 the leaves. The larvae upon hatching enter the leaf tissues and begin 

 feeding. In midsummer the egg, larval, and pupal stages coA^er 6, 

 17, and 21 days, respectively. 



The acridid Atractomorpha bedeli (7), though not an important 

 pest in Chosen, is often found feeding upon sugar beet and dry-land 

 rice. The eggs carry over the winter, and the adult stage is reached 

 by July. In only occasional instances are the nymphs and adults 

 sufficiently abundant to cause any appreciable injury to the plants. 



A species of pentatomid, Dolycoris hacearum (7), is in Chosen a 

 minor pest of sugar beet as well as of soybean and tobacco. The 

 injury results from the feeding of the nymphs and adults upon flower 

 buds, this causing the reduction in the crop of seed produced. There 

 are two broods each year, and the adults pass the winter in rubbish 

 or under stones. The eggs are laid in groups of 8 or 9 on the under- 

 sides of the leaves and hatch in 7 days. As means of control the 

 burning of all rubbish in the vicinity of the field is recommended as 

 well as the collection of egg clusters and of adults by knocking them 

 into trays containing kerosene. 



A collemboloid pest recently discovered in Hokkaido is the garden 

 springtail, Bourletiella (Sminthurus) hortensis (pruinosus Tullb.) 

 (3Jf, 78), which attacks various field and vegetable crops. The dam- 

 age is due to the cutting of the leaf stems of seedlings and young field 

 plants. There are several generations per year, and the adults of the 

 last hibernate in cells in the soil. The damage to sugar beet is great- 

 est during dry periods, as the species does not thrive under moist 

 conditions. Control measures used are the spraying of the young 

 plants at 5-day intervals with kerosene containing wood ashes and 

 pyrethrum powder, or the placing of sawdust soaked with kerosene 

 about the plants. This pest is recorded upon a wide range of plants 

 in the British Isles and Canada. 



INSECTS AFFECTING LEGUMES 



The soybean is the most important of the legumes grown in Japan, 

 and in Manchuria it is the principal agricultural crop. Kuwayama 

 (76) lists the following insect species as being the most injurious 

 ones attacking the crop in Hokkaido : Podisma pedestris sapporense, 

 Illinoia pisi, Luperodes suturalis ab. nigrobilineatus, L. discrepans, 

 Popillia japonica, Laspeyresia glycinivorella, Chloridea dipsacea, 

 Pyrrhia umbra, Colias hyale poliographus, and an undetermined 

 cecidomyiid. 



