408 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 84 



March, 1929, to the termination of his employment there was an 

 average parasitism throughout the entire territory of over 70 per cent. 

 This parasite was Trichogramma nana Zehnt. 



The second species was Diairaca htfuscateUa Zehnt. This borer 

 became the primary borer as the Olethreutes was reduced in numbers, 

 but its egg-parasite (Phanurus beneficiens) gained very rapidly under 

 the system of field redistribution, so that its parasitism was over 50 

 per cent at the time of leaving. Larval parasitism was very low, but 

 the same system of redistribution was followed and the mean para- 

 sitism of all borers showed an upward trend in a six month period. 



Extensive studies were made of the weevil borer, Trochorhopaliis 

 triangulatiis. This borer was unknown to the sugar planters, the 

 dominant pest of sugar cane on the Island of Negros, causing more 

 permanent damage than the dead-heart borers although the latter 

 were apparently causing 20 to 30 per cent injury. This is because the 

 dead-heart borers' damage was replaced by a subsequent growth 

 whereas the damage by the beetle borer was final. Tests were made 

 of the damage on many cars, and analyses in the mill proved that the 

 average damage was between two and three per cent loss of sugar, 

 which amounted to over a million pesos in the territory involved. No 

 parasites were found, but the obvious method of control seemed to be 

 the handling of waste. The practice in the Philippines is to burn the 

 waste after harvesting the cane, but usually large quantities of sticks 

 remained in the field. His recommendation, made in March, 1928. 

 to pick up and burn all pieces of cane left in the fields was prol>- 

 ably the most practical measure available at the time. This was fol- 

 lowed by many planters, and may be the reason for the gradual reduc- 

 tion in damage shown by investigations of the cars. 



The program of work followed out was divided into a survey of 

 the entire entomology of sugar cane and its surroundings, the map- 

 ping out of a complete program of cultural control,' and the distribu- 

 tion of parasites. The results of this work are embodied in a series 

 of six reports on the insects and one on the climate, published by the 

 Victorias Milling Company. 



Shortly after Doctor Pierce arrived at his Philippine post he wrote 

 nie that Dr. J. W. Chapman, a specialist on ants, was teaching zool- 

 ogy at the Silliman Institute at Dumaguete, Oriental Negros, and 

 that in addition to himself and Doctor Chapman the only other ento- 



' Doctor Pierce's recommendations in regard to cultural operations, involving 

 especially clean culture, were of such character as not to seriously interfere with 

 the generally adopted practice. They were economical and are likely to be 

 adopted in view of the resulting profit. 



