INSECTS INJURIOUS TO AGRICULTURE IN JAPAN 35 



following which the vine, or that portion of it attacked, withers and 

 dies. Hand collection of adults soon after emergence is the only 

 remedy suggested. 



A curculionid, Rhynchites lacunipennis (8), is recorded as a pest 

 of grape in Chosen. Though not of major importance, it is very 

 common and at times becomes sufficiently abundant to cause some 

 injury. There is one generation a year, and the winter is passed in 

 the adult stage in rubbish and other places that offer protection. 

 The adults emerge from their hiding places about the middle of 

 May, and oviposition begins a few weeks later. The eggs are laid 

 in groups of from three to seven in rolled leaves and hatch in about 

 one week. The larval stage covers a period of two months, and 

 feeding is completed within the rolled leaf. The larva then leaves 

 it and enters the soil for pupation. The pupal stage extends over a 

 period of 17 or 18 days. 



The curled leaves in which the larvae have developed fall to the 

 ground early in August. Transformation to the adult stage occurs 

 during the middle or latter part of that month, but the adults remain 

 in the soil until the following spring. When the insects become 

 sufficiently abundant to make control methods necessary these may 

 consist of the collection and burning of the rolled leaves during the 

 feeding period of the larvae and the shaking of the adults from the 

 foliage into receptacles containing oil, this being done as soon as 

 possible after the beetles have appeared on the vines in the spring. 



A single species of scolytid beetle, Xyleborus a/picalis (95), is also 

 recorded as attacking grape, though not extensively, it being pri- 

 marily a pest of apple. 



Gryllotalpa africana {107, 150), a gryllid species of wide distribu- 

 tion ranging from Africa through the entire tropical and subtropical 

 sections of Asia to Japan and Hawaii, is at times very abundant. 

 It is recorded as a serious pest on the island of Quelpart, the injury 

 being due to the feeding upon the tender roots of various plants. 

 Upon grape it is of only minor importance. There is a single gen- 

 eration each year, though adults and nymphs are present at all 

 times. The eggs are laid in nests in the soil and hatch in 25 days. 

 In the first nymphal stage the young remain in the nest and are fed 

 by the mother, but in the succeeding stages they fare for themselves. 



Erythroneura (Zygina) apicalis (91), a cicadellid endemic in 

 Japan, is recorded as at times causing considerable damage to 

 grape. There are three generations per year, and the winter is 

 passed in the adult stage in the grass along the field borders, in rub- 

 bish piles, and in other sheltered places. These adults emerge in 

 the spring, and the females deposit their eggs singly during the 

 latter part of April in incisions in the tissue of the leaf veins. The 

 second generation of adults aj^pears about the end of August and 

 the third in the latter part of September. To a considerable extent 

 these generations are overlapping, particularly the last two. The 

 greatest numbers are present during the autumn months, and the 

 infested leaves become grayish white owing to the withdrawal of 

 sap and consequent improper functioning. A heavy infestation re- 

 duces the crop by preventing the full growth of the fruit clusters. 

 The removal of the grassy borders along the vinej^ards is essential 

 in control, as well as the destruction of fallen foliage, rubbish, etc. 



