90 CIRCULAR 16 8, TJ. S. DEPARTMENT OF AGRICULTURE 



INSECTS ATTACKING BAMBOO 



Both in Taiwan and Japan bamboo is one of the most important 

 of forest products, the wood being used for a multitude of purposes 

 and the young shoots forming a staple and very palatable article of 

 food. Of the many species grown commercially four are used for 

 food, the shoots of these being gathered early in the spring when 

 they break through the surface of the ground. 



The most important pests of bamboo {102) are the noctuid Olhgia 

 {Polydesma) vulgaris in Japan, and Gyrtotrachelus Jongimanus 

 {longipes F.) and Acroceratitis plumosa in Taiwan. 0. vulgaris 

 is very injurious in the central and southern sections of Japan, and 

 the damage inflicted, according to Okada (1^), ranges from 30 to 

 90 per cent each year. The most valuable varieties are the most seri- 

 ously attacked. There is a single brood each year, and the winter is 

 passed in the egg stage upon the foliage. The injury is noticeable 

 only during June and early July, at which time the larvae are nearly 

 mature. There was for some time considerable doubt as to the 

 habits and host plants of the early stages, as the eggs hatch in May, at 

 which time no shoots of the commercial varieties are available. It 

 has since been found that the early stages are passed in the shoots 

 of the smaller forest bamboos, as these appear above the ground 

 much earlier in the season than those of the commercial varieties, 

 and that the larvae later migrate to them. The larvae bore into the 

 apex of the shoot when it is from 1 to 2 feet in length, and from 1 to 

 10 larvae may be found in each. The result of the feeding is a grad- 

 ual yellowing and finally the death of the shoot. Pupation occurs 

 in the soil, and the adults appear in late July and early August. 

 Shortly thereafter the eggs are laid in rows upon the leaves. No 

 practical means of control has as yet been developed, though it 

 may possibly be effected by the removal of the shoots of the forest 

 varieties in the vicinity of the commercial plantings during the early 

 spring. 



The curculionid CyrtotracheJus longimanus {87) is the cause of 

 considerable damage to young shoots in Taiwan. The adult female 

 makes a slit in the young shoot from 1 to 4 inches from the tip, 

 and in this 1 or 2 eggs are laid. Hatching occurs in four days, 

 and the larvae tunnel about in the growing stem, killing it and 

 rendering it unfit for food. When mature, the larvae leave the stem 

 and jmpate in the soil. Xo means of control is as yet known except 

 the collection of adults, and this is somewhat encouraged by the 

 fact that they are used as food by the natives. 



The trypetid fly, Acroceratitis plumosa {87), a species endemic in 

 Taiwan, is responsible for very extensive injury to the shoots in 

 the island. The adult flies are found throughout the year, but the 

 number of generations produced annually is not known. The eggs 

 are laid under the sheath of the young shoot, and the maggots bore 

 about in the tissue, causing it to decay. 



The nymphs of Notobitus meleagris {87). a coreid bug, at times 

 causes some damage by sucking the sap of the young shoot, though 

 usually they are not sufficiently abundant to seriously affect growth. 

 The eggs are laid on the sheath. 



Two phytophagous chalcids of the family Eurytomidae are recorded 

 by Ishii {Ifi) as attacking bamboo in southern Japan, these being 



