456 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



every year. Mr. Bovell stated that field experiments had shoA\Ti 

 that cutting out the dead hearts in the young cane caused so much 

 injury by root disease that more sugar was obtained from the untreated 

 cane. The greater part of the injury from Diatrcea occurs in the 

 upper portion of the stalk and possibly this is another reason why 

 the cutting out of dead hearts was not more successful. Trichogramma 

 minutum is the only parasite of Diatrcea in Barbados. 



The most interesting and important insect pest of cane in Barbados 

 from the standpoint of one interested in its parasitism and more 

 particularly the introduction of that parasite into Porto Rico, is the 

 brown hard-back, Phy talus smithi Arrow. The genus Phy talus is 

 closely related to the genus Lachnosterna, the grubs of which genus 

 are so injurious to cane and other plants in southern Porto Rico. 

 The grubs of Phytalus smithi never attain to more than half the size 

 of the Porto Rican Lachnosterna and they are never sufficiently abun- 

 dant to cause serious injury to the cane. The reason whj' they do 

 not become an important pest is probably because they are para- 

 sitized by a black wasp, Tiphia parallela Smith. 



A few years ago in the Island of Mauritius, the cane was at- 

 tacked by a root grub and in certain parts of the island it caused 

 an entire failure of the cane crop. The adults of this grub were 

 described as new bj' Mr. Arrow of the British Museum under the 

 name Phytalus smithi. A short time later, when Mr. Guy S. Marshall 

 was looking over a collection of local cane pests in Barbados, he 

 noticed beetles similar to the adults of the grub which was such a 

 pest in Mauritius^ and he decided they were of the same species. 

 It was then remembered that a considerable time ago new cane varie- 

 ties had been sent from Barbados to Mauritius. The usual method 

 of introduction was to send a few joints of a stalk of cane with the 

 ends sealed and packed in moist sawdust or charcoal, but some varieties 

 had been introduced by sending an entire stool of cane in a pot of soil. 

 It is quite probable that the grubs of Phytalus smithi were introduced 

 into Mauritius in the soil surrounding the roots of these new varieties 

 of cane. The parasite Tiphia parallela was not introduced with the 

 grubs, and vnih the parasite not present to check its increase, Phytalus 

 smithi became a serious pest. Although most strenuous measures of 

 hand picking the grubs and collecting the adults have been adopted 

 in Mauritius in the hope of entirely exterminating the beetle (for it 

 is a pest in only a comparatively small portion of the island at present), 

 it seemed very desirable to introduce the parasite Tiphia parallela 

 to aid in its control. Under the direction of Mr. J. R. Bovell in 



» Mauritius is a small island in the Indian Ocean, southeast of Africa. 



