15-t 



THE AGRICULTURAL NEWS. 



May 13, 1911. 



INSECT NOTES, 



THE FROG-HOPPER OF THE 

 SUGAR-CANE. 



The frog-hopper of the sugar-cane has been the subject of 

 Insect Notes in the A</rirulttiral Keirs on two previous occa- 

 sions. On the fir.st of these (see Af/ricultural A'ews, A'^ol. V, 

 p. 330) mention was made of the occurrence of this insect in 

 Trinidad before it was generally recognized as a serious pest, 

 and on the second (see Vol. IX, p. 346) an account of the 

 life-history, methods of control, and natural enemies, was given 

 after a considerable amount of work had been done in investi- 

 gating these points in conne.xion with an insect which has 

 rapidly assumed a position of importance in consequence of 

 the nature and amount of the injury it is able to cause to 

 sugarcane. The information contained in this latter article 

 was based on papers and reports published by Jlr. F. W. 

 Urich, Entomologist to the Board of Agriculture, Trinidad. 



Since the appearance of the articles already mentioned, Mr. 

 Urich has issued a paper on the identification of the sugar-cane 

 frog hopper (I'roceedivr/s of the Af/rindtural Societt/ of Trini- 

 dad find Tohaijo, Vol. X, p. 52.5) in which it is stated that 

 this insect has been re-identified, and should be known as 

 2'omaspis -!«/■;'«, Fabr., instead of 'l'(i)iiiii:pis jmstica, Walk., as it 

 has been known for several years. Other species of Tomaspis 

 are recorded on a variety of food plants. 



Additional information in regard to this pest has been pre- 

 isented in a paper by Dr. L. H. Gough, entitled liesults Obtain- 

 ed in the Study of the Frog-hopper 1 )uring the Wet Season of 

 1910. In this account of the Frog-ho|iper, the author summar- 

 izes the previous knowledge and the previous literature of the 

 subject. As an instance of the amount of injury and loss 

 that may be occasioned by this insect, it is stated that on one 

 estate 150 acres nf sugar-cane attafked by frog-hoppers gave 

 a yield averaging 10 tons of cane per acre less than probably 

 ■would have been obtained if there had been no attack, and 

 the 1,.500 tons of canes thus lost represented a value of 

 £1,800, which was lost to the estate. 



In discussing the methods of control to be employed. 

 Dr. Gough gives an account of several spray mixtures and 

 solutions which have been tried or suggested, with directions 

 for ])reparing them and details of their cost, and the expense 

 of application. Several spraying machines are described, and 

 particular attention is given to a nozzle designed by the 

 author for the jmrpose. This nozzle has for its special feat- 

 ures: the length (about 2 feet), which enables the operator 

 to apply the spray fluid to the centre of the cane plant 

 without cutting his hands on the cane leaves; the bend or 

 curve near the top, which enables the stream to be directed 

 downward while the nozzle is held at a convenient angle in 

 the hand; and the automatic cut oil', which enables the opera- 

 tor to control the spray, thus obviating waste and saving 

 labour. This nozzle delivers the spray fluid in a very fine, 

 solid stream, and not in a mist-like spray. 



Kerosene emulsion and kerosene-lysol mixture are highly 

 recommended, and the directions for preparing and applying 

 these are very complete. 



The object of spraying is to kill the adult frog-hoppers, 

 .since the egg by its position, and the immature stages, also, 

 or by their covering of spittle, are protected from the success- 

 ful action of insecticides. 



The cost of spraying with the kerosene emulsion 

 is given as S'l'Glj per acre for labour and materials, 



when materials are purchased at Trinidad prices, or -^l^lf 

 per acre when materials are procured duty free. Other 

 methods of control which are reported as giving good results 

 in 1910 are the use of trap lights, the capture of mature 

 insects and the burning of trash after the crop. The trap 

 lights are inexpensive, both in the first cost and in that 

 of attendance and maintenance; but it is noted that the 

 greater part of the frog-hoppers captured are males, the 

 females amounting only to about 1 to 2 per cent. 



The object of burning the trash is the destruction of the 

 eggs, which are deposited in the dry, dead portions of the 

 cane. 



The artificial dissemination of the frog-hopper fungus is 

 also discussed at length, and is apparently considered as 

 a method of control likely to yield very satisfactory results. 

 Reference to the use of the fungus was made in a previous 

 number of the Agricultural News (see Vol. IX, p. 3.50). 



SUGAR-OANE BORERS IN 

 GUIANA. 



BRITISH 



An interesting account of the giant moth borer (Castnia 

 licus) and other sugar-cane pests in British Guiana has just 

 l)een received, in the Interim Report on Insect Tests by 

 Mr. John J. yuelch, B Sc, April 1911. 



It appears from the report that the practice of flooding 

 the fields immediately after the crop is taken off is likely to 

 furnish the most practical method of dealing with serious 

 attacks. 



The collecting of adults and grubs continues to be 

 carried on, and is counted a valuable aid to flooding in 

 severe infestation, and a fairly satisfactory means of control 

 where this is slight. 



The protection and encouragement of birds which prey 

 upon the moths is stronglj- recommended; it is stated that 

 the burning of the trash in the field destroys and drives 

 away many beneficial insects, especiall}- small internal 

 parasites. 



Slight outbreaks of the giant moth borer have not 

 developed into serious proj)ortions in several localities. This 

 indicates that, in these instances at least, the natural enemies 

 are working fairly satisfactorily, and that this control has 

 been exercised even when outside sources of infestation were 

 not far distant. 



The smaller moth borer {Diatraea sacckaralis) has been 

 carefully studied, and it ap[)ears that three species have been 

 commonly associated un<ler one name. Mr. Quelch repoits 

 that he has identified Diatraea canella, D. sacckaralis, and 

 D. limolafa, which are similar in aiipearance and vary 

 but little in size. 



The cutting out of dead hearts and the removal of the 

 caterpillars causing the injury are recommended as remedies, 

 and it is stated that many young larvae of the giant 

 moth borer are removed by this process before they have 

 penetrate<l too dee[)ly into the cane. It is advised that this 

 work be entrused to reliable labourers cqui[>ped with suitable 

 sharp knives, and that great care be exercised to cut low 

 enough to remove the caterpillar and at the same time not to 

 injure the remaining canes in the stool. 



The eggs of the small borers are attacked by twO' 

 .species of parasites, which appear to be fairly abundant at 

 certain times. These minute insects are probably greatly 

 reduced in numbers by the practice of burning the trash. 



