138 



THE AGRICgLTURAL NEWS. 



April 30, 1910. 



INSECT NOTES. 



NATURAL ENEMIES OF SUGAR-CANE 



PESTS. 



The control of inject pests by means of their natural 

 enemies is being attempted on a large scale in many parts of 

 the world. The largest of these trials is perhaps being made 

 in connexion with the gyps}' moth in massachusetts, while 

 the results that have been obtained in the control of citrus 

 pests in California, and of sugar-cane pests in Hawaii, are 

 .sufficiently striking to attract attention. Mention has also 

 been made in a recent number of the Ai/ricultural JS'ews of 

 the results obtained in Florida by means of the fungoid para- 

 sites of certain scale in.sects. 



Mr. F. Muir,an entomologist on the stall' of the Hawaiian 

 Sugar Planters' Experiment Station, has recently visited 

 islands in the Malay Archipelago in search of parasites of the 

 sugar-cane borer {Sji/ienophorvs obscurus) for introduction 

 into Haw.aii. An interesting account of the entire trip has 

 appeared in the Hdwaiidn t:>u(iar Fl(inter» Monthbi, in the 

 numbers for September and November, 1909. The first of 

 these was reviewed in the Agricultural News (see Vol. YIII, 

 p. 393), where it was mentioned that three parasites had been 

 found. One of these is a Tachinid fly, one a Histerid beetle, 

 and one a beetle of the family Elateridae. 



The Tachinidae are a family of the order l)iptera, well 

 known for their parasitic habits. The Hisleridae are beetles 

 of diverse habits, a few being predaceous, but the greater 

 number are feeders on decaying and fermenting matter of all 

 kinds. 



The Elateridae are the click-beetles or .skip-jacks, whose 

 larvae, known as wire- worms, for the most part feed on the 

 roots of plants, and many species are injurious to cultivated 

 crops. The large fire-Hies {PirropltorHs noctilvcn), common 

 in many of the West Indian Islands, also belong to this 

 family. It is of interest that members of these two families 

 of beetles should be discovered to be parasitic in habit. 



The second part of Mr. Muir's report gives an account 

 of his visit to New Guinea (Paima). Here he found the 

 Sphcnophoriii' borer holding a .secondary position as an enemy 

 of sugar-cane; a very large proportion of the borers collected 

 were parasitized. The most prominent in.sect pest of 

 sugar-cane was a moth borer related to Diatraea which 

 was not held in check to anything like the same extent as 

 the Spheno2jhorus, by its insect parasites. 



It should be mentioned that, in the localities where the 

 parasitized borers were found, sugar-cane is not grown for 

 the purpose of sugar-making, but rather for eating. 

 Each native grows a few stools of sugarcane in his garden, 

 where it produces seed freely, from which young plants 

 readily spring. It would thus appear that the sugar-cane 

 plant grows under the most natural conditions in New 

 Guinea, and that where these prevail, the plant, the pests, 

 and the enemies of the pests should all occur under those 

 circumstances which establish a balance of nature. 



Mr. Muir was taken ill in Brisbane and was unable to 

 accompany his cage.s containing parasitized borers on the long 

 journey from Australia to Honolulu, and the parasites 



received no attention. As a consequence, none of them 

 were alive on arrival at Honolulu. Mr. ^luir believes 

 that with the experience he has gained, he will be able on his 

 next visit to Papua to keep the parasites alive until they 

 arrive safely in Hawaii. 



In addition to the efforts that have been made in Hawaii 

 to introduce the natural enemies of the pests which occur in 

 those islands, ver}' stringent laws have been passed with the 

 obji.'ct of preventing the importation of additional pests. 



With regard to the danger of importing these into 

 Hawaii, Mr. Muir writes in his report : ' When I consider 

 the numerous species of insects that I have found living on 

 sugar- cane in the various places I have visited during the 

 past three years, some belonging to groups of which we are 

 quite free at present, any one of which might prove as 

 destructive as the leaf hopper or beetle borer, I then fully 

 recognize the necessitj- of keeping the strictest supervision 

 over all imported plants and fruits.' 



The investigations in connexion with the sugar-cane borer 

 in Hawaii should be of interest to sugar planters in the West 

 Indies, on account of its similarity to the weevil borer in this 

 part of the world. 



In the Hawaiian Islands the sugar-cane borer has beea 

 known as a pest of canes since 186.5, and in 1904 the 

 damage caused by this was estimated at 8500,000. The 

 larva is known is, a borer in bananas, the royal palm (palmiste) 

 and the toddy palm (Oreodoxia re;/ia and Cnrpota iirens) and 

 the papaw {Carica Pajjai/a). In the West Indies the weevil 

 borer (Sp/wnophorus sej'ireus) is known to attack sugar-cane 

 oidy, while a related species (S. sordidus) attacks bananas in 

 certain inlands. The attacks of the weevil borer in the West 

 Indies were much more severe a few years ago than they are 

 reported to be at present. It is a question as to whether this 

 has come about as the result of the more universal cultivation 

 of newer varieties, or from the practice of burning rotten 

 canes, which is more general now than formerly, or as the 

 improvement due to the control exercised on the borer bj- 

 natural enemies. 



Mr. Muir writes that the reintroduction of soft canes 

 into Fiji frrmi Queensland has been accomjianied b}' an 

 increase in the severity of the borer attacks. l!y ■ soft cane ' 

 is probably meant a cane having a soft rind, and the 

 difference between hard and soft cane may be illustrated by 

 some of the seedling canes and by the Bourbon. 



FOREST ENTOMOLOGY IN THE UNITED 

 STATES. 



The Repart of th- Entomoloijint, United States Depart* 

 ment of Agriculture, for 1909, gives information that the 

 last piece of work of the Bureau during the year was 

 connected with plans fcpr co-operating with a State entomolog- 

 ist in making a survey to determine the principal insect 

 enemies of forest trees, as well as the damage done by them, 

 an assistant being provided by the State, who will work 

 under the immediate instructions of the Bureau, subject to 

 the approval of the State entomologist. By this means, 

 a field of survey and practical control work will be opened 

 up, so that an}- state, by the expenditure of a comparatively 

 small sum of money may obtain authoritative advice, based 

 on wide investigation. At the same time, the Bureau will 

 be in the possession of a valuable means of obtaining 

 information foi' subsequent dissemination and of making 

 practical demonstrations of methods of insect control. Such 

 work will lead to a more general recognition of the 

 importance of the subject, and of the measures by which the 

 damage to forests by insects may be minimized. 



