179 



callus tissue. They continue feeding during the growing period of 

 teak and prepare to pupate towards the end of the cold weather 

 or as soon as the leaves begin to fall. Woodpeckers are the chief 

 natural enemies. The larvae are parasitised by Tachinid flies, possibly 

 belonging to two species, and at least one species of Hymen- 

 opteron. They are also attacked by a fungus, (?) Cordyceps sp. 

 Other bee-hole borers of teak include the moths, Phassus signifer, Moore, 

 and P. malabaricus, Wlk., and the Longicorns, Aristohia hirmaniaim, 

 Gahan, and Haplohammns cervinus, Hope. 



Some statistical data are recorded in detail, and certain of the 

 conclusions arrived at are that vigorous trees are attacked by 

 D. cer amicus in preference to weak or decadent ones. The average 

 number of holes per tree is directly proportional to the girth. 

 Individual trees frequently escape attack for several years. The 

 liabihty of larvae to successful development is proportional to the 

 richer food supply afforded by vigorous trees. The annual incidence 

 curves show that the borer usually appears early in the life of 

 the plantation, and may appear as early as the second year after 

 foundation. The most important fact arising from the data is the 

 recognition of a very low rate of increase and frequent natural reduc- 

 tions in the mean annual incidence. This suggests that a possible 

 method of control in plantations lies in the production of a high girth- 

 increment in individual trees, so that the wood-increment outstrips 

 the borer-increment. There are indications that thinnings can be 

 carried out so as to reduce the incidence of the borer. The data on the 

 effect of undergrowth are contradictory, and the conclusions arrived 

 at in 1918 are not of general application [c/. R.A.E., A, vii, 135]. 



In plantations and regeneration areas of pure teak of more or less 

 even age the following remedial measures are suggested. Thinnmgs 

 should commence early and recur at short intervals, and they should 

 be carried out so as to produce a high girth-increment in individual 

 trees. In early thinnings or cleanings, trees showing bee-holes should 

 be cut out unless their retention is essential, but in the middle 

 period of the rotation the presence of visible bee-holes should 

 not influence the selection or rejection of trees. In thinnings the 

 suppressed and dominated trees should be cut out and not left standing, 

 as it is evident they do not act as trap trees, but are sources of 

 infestation in the more vigorous ones. The most favourable time to 

 fell is between August and December. If trees are felled early in the 

 year, the borers in the mature larval and pupal stages will complete 

 their development successfully. 



Beeson (C. F. C). Recent Work in Forest Entomology.— Kept. 



Proc. 4th Ent. Meeting, Pusa, February 1921, Calcutta, 1921, 

 pp. 182-183. 



Studies have been carried on during the last two years on the borers 

 of sal {Shorea robusta) and the trees associated with it in sal forests, 

 and of teak {Tectona grandis) and its associates. The most important 

 sal borers are Hoplocerambyx spinicornis, Aeolesthes holosericea and 

 certain Platypodids. The first-named has occurred in epidemic 

 incidence as a primary pest killing living sal trees [/?. A.E., A, ix, 216], 

 though normally it is a borer of felled or killed timber. The effect 

 of rainfall on the metaboHsm of the early larval and pupal stages 

 has been studied, and it has been found that the incidence of emergence 



