282 



THE AGRICULTURAL NEWS. 



August 30, 1913. 



INSECT NOTES. 



SUGAR-CANE PESTS IN BRITISH GUIANA. 



In tlie last issue of this journal, the first article on the 

 sibove subject concluded with a reference to the small moth 

 borer (J)ia(raea spp.), and the collection of its caterpillars 

 and chrysalides. The subject is now continued in regard to 

 egg collection. The number recorded for the year, from five 

 estates wa.s 281,181. 



On one estate, as many as 8,000 egg clusters were 

 gathered in a single day. The figures given for two 

 estaii's show that in each case there are two periods 

 during the year when the collections are at their greatest. 

 These are in January, February and March, and in August, 

 ••September and October. It is stated that these are the 

 times when there are large areas of young canes through 

 which the collecting gangs can work: also that these 

 limes correspond to the periods of greatest egg-laying. 



MKTHOl) OK lOLLEiTINi: ICGl^s. 



The collection of eggs is strongly recommended as being 

 capable of development into an effective means of controlling 

 the small moth borer. Not only may thousands of caterpillars 

 be destroyed without having any opportunity to damage the 

 canes in the least, but this may be done in such a manner as 

 not to interfere with the development of the egg parasites. 

 The following procedure is the one generally adopted; The 

 egg clusters are collected on small pieces of leaf, and each days 

 catch is taken to the factory yard or watch house where they 

 are kept for four or five days in suitable vessels (such as 

 small saucepans or skillets), which ciin be stood over, or in 

 molasses or oil and water to prevent the access of ants or the 

 escape of any caterpillars which may have hatched. The 

 covers of the vessels should not be closed so lightly as to 

 prevent the caterpillars from crawling out, otherwise they 

 would feed upon the pieces of cane, and incidentally would 

 destroy the eggs and all the parasites which might be 

 contained in them. 



N.\TUR.\L ENE.MIKS SET FIIUE. 



The portions of cane, with the egg clusters on them, are 

 taken to the cane field and placed in receptacles, protected 

 from the weather, and so arranged that the parasites may 

 escape but without allowing the caterpillars to do so. This 

 is accomplished by using a tobacco or cigarette tin soldered 

 in the middle of a shallow pan 5 or 6 inches in diameter. 

 The tobacco tin receives the egg clusters on the portions of 

 cane leaf, while the pan holds water and oil to prevent the 

 caterpillars from getting out. 



This arrangement of a tin in a pan is placed in the field 

 inside a box nailed to a sharp stake about I feet high, 

 which can be easily driven into the ground. The box is 

 open on one side to allow the parasites to fiy out, and the 

 open side is turned to leeward so that the rain will not be 

 driven in by the wind. 



I.MPOET.AKCE OK CANE .SELECTION. 



Traplights have been tried but they have not been very 

 successful. In addition to the cutting out of dead hearts 

 and the collecting of egg clusters, — methods which are 

 strongly recommended — -attention is given to indirect aids 

 to control, prominent among which are: (1) the production of 

 healthy vigorous growing canes, and (2) the use of resistant 

 varieties. 



The first of these important objects is to be achieved by 

 careful selection of tops for planting, and stumps for tupply- 

 ing, to guard against the -use of any plant material affected 



by insects, especially borers. The system at present ia. 

 vogue is stated not to be rigid enough; that is, sufficient care 

 is not exercised to see that the very best tops onfi/ are u.^edi 

 for planting. Selection is imjiortant in order to ensure the 

 right start of a healthy plant. To maintain this condition, 

 of healthfulnes.s all the operations of drainage, tillage, weed- 

 ing and manuring must be given careful attention also. 



B0URI;0N CANE RESISTANT. 



The discussion of'the second of these indirect aids — 

 the use of varieties of cane resistant to moth borer attack — 

 brings out the fact that in British Guiana, the Bourbon cane- 

 is less attacked by the small moth borer than are many of th» 

 seedling varieties. The author of the report suggests that if 

 the fungoid diseases could be controlled so as to allow the 

 re-establishment of the Bourbon on a large scale, the losses- 

 due to moth borer would be greatly reduced. 



FUETHfiR SUGGESTIONS. 



It is also strongly advised not to burn the canes. The- 

 reason for this is because large quantities of trash, of value 

 as a source of humus in the soil would be wasted, and large 

 numbers of useful parasitic insects destroyed at the same- 

 time. 



It is further suggested that there should be less ratoon- 

 ing or, if possible, none at all. Ratoon canes suffer more 

 from attacks of the small moth borer than plant canes. 



In addition to the egg parasites, Trichoriramma pretioga 

 and an unindentified species, there are, in British Guiana, 

 at least two hymenopterous parasites of the caterpillar, 

 which deposit eggs in the moth borer tunnels close to the 

 borer after having stung it and rendered it helpless. Thu* 

 when the egg of the parasite hatches, its grub at once begins 

 feeding on the borer. 



TERMITES ANI> OTHKK PEST.S. 



The wood ants or termites are stated to come next to>- 

 the small moth borer in point of severity of attack, and the 

 amount of loss occasioned. 



These insects infest the cane underground. When 

 young plants are attacked, a large amount of supplying is- 

 often necessary, and when the older ripening canes are 

 troubled, often the entire stool is destroyed. The removal 

 and burning of the termite nests after the canes are reaped 

 is recommended as the principal means of checking the 

 pests, and it is stated that when the insects are particularly' 

 abundant, the Hooding of the fields for a few days is a very 

 effective mode of destruction. The practice of flooding isi 

 also recommended as a remedial measure in connexion with 

 other cane pests, and appears to be worthy of much more- 

 extended employment. 



The weevil borer {.Velainaxins [Sphenophorus] henip- 

 Ufuii) was present on all estates but aoundant on only a few; 

 This insect attacks the stools after the canes have been cut, 

 it also infests plant tops in the ground, and growing canes 

 that are injured by rats or the moth borer 



Other insects, the occurrence of which is mentioned, 

 are: the coco-nut palm weevil {Rhyiichophorns jjalmurum); 

 the hard back beetles Dysciiulua liidentaiitx and C ydocepluiltt 

 siynata; the shot borer (Xylehornx sp.); the sugar-qane 

 aspidiotus (As/iidiotits sacchari): the pink mealy-bug (Pseit- 

 ilococcas ca/ccolarkw). A leaf hopper and a froghopper 

 (Toiii'ispis s]! ) were observed in very small numbers. The 

 cane stool moth, the larva of which feeds on decaying and 

 damaged cane stools, the dead cane moth (Monode^ wjrotimty 

 and several leaf-eating caterpillars, such as Rei.iigiu rejiiinda, 

 Lap/i»;jiu'i t'ru'jipenia and f.i/'op/totia iiifecta arc also 

 recorded. 



