378 



THE AGRICULTURAL NEWS. 



November -li, 1913. 



INSECT NOTES. 



IKMEDY. 



A PEST OF ORANGES. 

 The occurrence of a pest causing injury to oranges in 

 Dominica, has recently been reported. 



lUSTORlrAL. 



This pest was first reported to this Department towards 

 the end of 1907 when a few injured oranges were .submitted 

 for examination. 



In 190S, a further bad attack wa.s experienced, and an 

 investigation of the conditions was made by the Acting 

 Curator, who submitted a preliminary report on the habits 

 of the insect and the nature of the injury. That officer also 

 recommended certain remedial measures which were tried. 



The Entomologist of this Department recommended an 

 additional measure, viz., spraying with arsenate of lead, 

 ■which was tried in 1909 with such satisfactory results that 

 the pe.st was .reported to be completely under control, and 

 this satisfactory state of affairs was again reported in the 

 following season (1910). 



Since that time no record of the insect has been 

 received at the Office of the Imperial Department until 

 October of the present year. 



THE INSB^T. 



The insect concerned in this attack is a small moth 

 apparently of the family Tortricidae, but only a few speci- 

 mens of the adult have yet been secured and its identity 

 has not been established. 



It would appear to be related to the codling moth 

 {Citrpaiapsa p<mif>nella), and to the Natal codling moth 

 {Enminonia hatravhopn), both of which are Tortricids which 

 injure fruits in a manner similar to that of the orange pest 

 in Dominica. 



H.\1!ITS OF THE INSECT. 



From the reports of the agricultural officers in Domi- 

 nica (the Acting Curator in 190.S and the Assistant Curator 

 in 1913), it would appear that the attack begins in May or 

 June, the egg being laid on the surface of the fruit, and 

 the larva (a small caterpillar) penetrating through the rind 

 into the interior of the orange. During Augu.st, the larval 

 stage is completed and the full grown caterpillar leaves the 

 fruit (which by this time has fallen to the ground) and enters 

 the pupal stage amongst the leaves on the ground. About 

 two weeks later the moths emerge. What l)ecomes of the 

 insect during the period from about September or October to 

 the following May or .Tune is not known. 



IN.IURV TO THE FRUIT. 



The insect injures the fruit by penetrating the skin and 

 living and feeding in the pulp of the orange. Often the 

 characteristic puncture of the skin is seen, when on cutting 

 open the fruit, no injury to the interior is found. It is 

 likely that in such cases, the attack was begun on a very 

 young fruit, in which the growth was so rapid as to prevent 

 the development of the caterpillar. 



In other instances, the larva successfully penetrates to 

 the pulp where it feeds and completes its development, caus- 

 ing a portion of the pulp to become a di.scoloured, rotten 

 mass. Even when no further injury is caused than the 

 puncture of the skin, the fruit is rendered unsaleable, on 

 -account of the discoloration at the point of attack and the 

 malformation which often results. 



Several reuicdial measures have been tried, the most 

 successful of which appears to be arsenate of lead applied as 

 a spray early in the season, in order that the newly batched 

 caterpillars may be poisoned as they attempt to eat their way 

 through the orange skin. 



CAUTION. 



Growers of oranges who may observe appearances leiding 

 them to suspect iha^ presence of this pest on their fruit 

 should inform the local agricultural officers, forwarding 

 specimens and asking for advice as to the treatment to be 

 adopted. -* 



INSECT PESTS AT ST. CROIX. 



Tlie Report of the Director of the Department of 

 Agriculture, St. Croix (D.W.I.), for the year ended June 30, 

 1913, was reviewed in the previous number of the A(fricid- 

 tural News (see page 363) from the advance copy forwarded 

 to the Imperial Commissioner The portion relating to 

 insect pests is briefly dealt with in the present and succeed- 

 ing articles. 



The chief insect pests recorded in this report are those 

 which attack sugar-cane and cotton. 



The most important pest of sugarcane in St. Croix is 

 the rhinoceros beetle {Sti-ater/a-f titanns), the larva of which 

 attacks the roots of the growing plants, and tunnels its way 

 into the stalks for a considerable distance. This insect has 

 been mentioned in the Agricultural News, Vol. XI, p. 3-16, 

 and Vol. XII, p. 170, where an account of its habits, life- 

 history and distribution is to be found. 



The grubs of the rhinoceros beetle usually live in 

 decaying megass, but in certain years they have been a most 

 serious pest of growing canes. A similar insect occurs also 

 in Porto Rico. 



The grubs are to be found abundantly in cattle pens and 

 megass heaps, and when these exist in the cane fields, the 

 badly attacked stools of cane appear to be dying of drought. 

 If such stools are uprooted, grubs may be found among the 

 roots and often in their large tunnels in the stalks. During 

 the season under review these grubs have seriously attacked 

 cane plants and young cane sprouts. In a portion of a field 

 at the Experiment Station about 80 per cent, of the canes 

 were destroyed. 



A simple and effective remedy has been found in the 

 use of a poisoned bait consisting of 100 parts by weight of 

 fine megass and 3 parts of Paris green, thoroughly mixed 

 together. This poison is used in the following manner: 

 A hole is made with a drill beside each [)lant and a handful of 

 the poisoned megass placed in it. After a few days the baits 

 are examined, and large numbers of dead and dying grubs 

 are found in and near to them. This treatment of badly 

 infested fields has been found entirely successful. It is 

 suggested that badly infested fields should be thrown out of 

 canes for a season, the stumps dug out and burnt and 

 a rotation crop— cotton-^planted after careful preparation of 

 the land. Between the rows of cotton the poisoned megass 

 bait should be drilled in every 3 or 1 feet. 



The pink mealy-bug is of fairly frequent occurrence, 

 causing a considerable amount of damage to canes, especially 

 the young canes. It attaches itself to the roots of these 

 at the base of the stools and to the nodes just above ground. 

 The remedy to be adopted is to use no cane for planting 

 on which the mealy-bug occurs. 



A summary of the observations on cotton and the 

 remaining cane pests will appear in the next issue. 



