INSECTS INJURIOUS TO AGRICULTURE IN JAPAN 75 



MELON INSECTS 



The most common of the melon pests in Japan, Chosen, and Tai- 

 wan are the chrysomelid beetles Rhaphidopalpa (Aulacophora) 

 femoralis, R. foveicollis, and Geratia (Orthaulaca) atripewnis. The 

 first is found throughout Japan, except Hokkaido, and in Chosen 

 and Taiwan and causes considerable damage to young cucumber and 

 melon plants. It also was observed on several occasions in central 

 Honshu to attack soybean in numbers. There is one generation a 

 year, and the adults appear in the field largely during June. 

 According to Shiraki (169) the two last-named species cause much 

 damage to cucurbits in Taiwan, and the larvae of R. foveicollis occa- 

 sionally bore into roots, causing the plant to wither and die. The 

 most generally employed means of control is the covering of the 

 young plant during the first few weeks of growth with a light cloth 

 supported by a pair of arched bamboo sticks. 



The melon fly, Dacus ciocurbitae (169), is one of the major pests of 

 various cucurbits in Taiwan and southern China and is particularly 

 injurious during the latter part of the season. Its life history has 

 not been studied in detail, but during the summer is probably very 

 similar to that of the same insect in Hawaii where, according to Back 

 and Pemberton, a generation covers a period of approximately six 

 weeks during the coolest part of the year. 



A species of melon fly (apparently Ghaetodacus sp., not D. cucwr- 

 bitae, according to Doctor Miyake) (187) is reported from Gifu 

 Prefecture as occurring in pumpkin, but nothing further is known 

 regarding it. 



The mole cricket Brachytrypes portentosws (169) is of more im- 

 portance as a melon pest than as a pest of any other of the numerous 

 and varied plants which it attacks. In Taiwan it attacks chiefly 

 young plants of nearly all kinds, and upon young melon plants in 

 the coastal sections feeding is so extensive as to result in complete 

 defoliation and the destruction of the crop over large areas. The 

 nymphs and adults cut off large quantities of leaves and young 

 snoots and carry them into the burrows. There is one generation a 

 year, the adults appearing in May and June, and the females deposit- 

 ing their eggs in September. The eggs are laid from 1 to 2 feet 

 below the surface of the ground and hatch in about one month. The 

 young nymphs feed only at night, and the burrows into which they 

 carry the collected foliage extend about 6 inches under the ground. 

 Flooding is recommended as a control measure, but in orchards, cane 

 fields, and tea gardens this is not practicable. Poison baits give 

 satisfactory results, and sweetpotato has been found to be the most 

 satisfactory carrier. The buds or young shoots of bamboo are even 

 better for this purpose, but the difficulty of collecting a sufficient 

 quantity makes their use impracticable. 



STRAWBERRY INSECTS 



The strawberry weevil, AnthonowMS signatm, is of wide distribu- 

 tion m Japan and attacks wild rose in addition to strawberry. Ac- 

 cording to Kinoshita and Shinkai (4,7) a single generation is pro- 

 duced each year, and the winter is passed in the adult stage in shel- 

 tered places. The adults emerge in April and begin feeding upon the 

 flower buds. The eggs are laid singly in holes made in the bud 



