394 



THE AGRICULTURAL NEWS. 



December 6, 1913. 



INSECT NOTES. 



INSECT PESTS AT ST. OROIX. 



In the last issue of the Agncultural News an account 

 of the chief insect pests of sugar-cane, dealt with in the 

 Annual Keport of the Agricultural Department, St Croix, 

 was published. The remaining pests of the sugarcane and 

 those of cotton will now be described. 



The moth borer of sugar-cane in St. Croix is a serious 

 pest For its control it is recommended to collect and burn 

 all infested and rotten canes immediately after the crop is 

 reaped, and to plant no cuttings in which any borer holes 

 are to be seen. The weevil borer {Sjihenophoms serireus) 

 occurs in cane fields in St. Croix each season. It can be 

 controlled by the prompt collecting and burning of all rotten 

 canes after the crop is reaped. Root borer grubs, similar to 

 those of Diuprejifs a/i/o-eriatus in Barbados, have been found 

 at the base of cane plants in St. Croix, but these do not 

 appear to cause any considerable amount of damage. 



A large longicorn beetle, Lagochirua araneiformis, has 

 in one instance, been discovered as a borer of canes at the 

 Kxperinient Station. Several grubs, a pupa and two adult 

 beetles were taken from canes which were being reaped. As 

 this insect is generally distributed throughout the West 

 Indies and in Central Africa and has not before appeared as 

 a pest of sugar-cane, it is likely that the attack on 

 sugarcane here reported is an accidental occurrence, and 

 that but little is to be feared from future attacks. 



roTToN. 



The pests of cotton in St. Croix are mostly the same as 

 those occurring in the adjoining islands of the Leeward group. 



The cotton worm {Aladama aryillacra) appeared at 



everal times during the season and was controlled by the 



»se of Paris green and lime. There were complaints of 



ajury to the leaves by the Paris green, and planters were 



scommended to use for the purpose dry arsenate of lead 



ixed with lime. It was found that this poison, though 



ower in its action on the cotton worm, did not injure the 



leaves, and it remained on the plants longer than the Pari.s 



green. The cotton worm is also controlled to some extent 



by natural enemies. 



The cotton boll worm {Ilcliot/iis obsolc(a) is probably 

 the most serious pest of cotton in St. Croix. Four other 

 caterpillars also attack the flower buds and bolls of cotton 

 plants in St. Croix. These are Prodenin ornathogelli and 

 F. latif'iscia, and two which have not yet been identified. 

 The attacks of the.se insects caused a very considerable 

 amount of loss to cotton planters during the season. An 

 extended trial was made of tlie use of trays containing 

 molasses for catching the moths; a large degree of success 

 is reported. 



These trays were small in size, about 1 square foot in 

 area; they were partly filled with molasses and placed on the 

 ground in the cotton field, about ten trays being used to 

 each acre. The catch of moths each night araounteil to 

 some 400 to 500 per tray, with the result that the 

 abundance of the boll worm was greatly reduced. The 

 report does not state, hcwaver, how many different species 

 of moths and other insects were caught in this manner. 

 Arsenirte of lead applied in a dry condition as for cotton 

 worm is considered likely to be useful, as a check on the boll 

 worm when it passes from one boll or bud to another. 



Boll worms are parasitized by a Sarcophagid fly to som& 

 extent: this is probably of value in the natural control of 

 this insect. The fiery ground beetle (C'do^Oina calidmn) is 

 another natural enemy of value in this connexion. 



The green stink bug or leaf bug {Nezara riridida) caused, 

 a considerable amount of damage in one locality, by sucking 

 the juice from the plant causing the bolls to drop. 



This insect was found to lay its eggs on wild Massambe 

 {Cleome viscosa), and on the fireweed {Datura metal) and plan- 

 ters were advised to destroy these plants wherever they were 

 seen. The wild Massambt- generally comes in and covers any 

 field if allowed to lie fallow after cotton. A quick growing 

 cover crop should be planted to prevent this. Sweet potatoes, 

 Lyon bean, pigeon peas, or Guinea corn are recommended for 

 this purpose. 



The leaf-footed plant bug {P/tptoplossus gotiandra) 

 appeared on certain fields for a short time only, and caused 

 some loss from boll dropping and injury to bolls by the 

 punctures made in feeding. 



The cotton stainer in St. Croix is the white-marked 

 stainer {Dysderms andreae) which occurs in the Leeward 

 Islands. 



Cotton stainers were prevalent in St. Croix in large num- 

 bers during the year under review than in the previous season. 

 At the Experiment Station they were so abundant that 

 spraying with kerosene emulsion was resorted to. The usua! 

 practice is to knock them off the plant.s into tins containing- 

 kerosene and water. 



Leaf-blister mite {Erioplq/es gossppii) has been a pest of 

 such a serious nature that an Ordinance was passed (190S) to- 

 provide for the uprooting and burning of all old cotton after 

 the first and second pickings had been secured. As the law 

 now stands, it provides for a close season, that is, a season 

 during which no cotton shall be grown on any given estate 

 or in any given district. The time for the close season is net 

 the same for all estates and all districts, but is fixed yearly 

 by a commission. It would appear from the report that the 

 kw works well and that a close season is essential in order to 

 keep the leaf-blister mite within reasfinal>le bounds It is 

 stated that the mites are carried about from plant to plant by 

 the moths of the cotton worm. 



Cut worms were controlled by the use of a teaspoonful of 

 poisoned bait placed near each spot where the seed is planted. 

 The bait is made by mixing together into a stiff paste 50 B>. 

 bran (pollard), and 1 lb. Paris green with molasses and water. 



Mealy-bugs (l)actylopius) and the cotton aphis were 

 ebserved on cotton, the latter abundantly during ttie dry 

 weather. These are preyed upon by the lady- birds and 

 syrphus tly larvae, which probably exercise a fair degree of 

 control over them. A species of a Diaprepes weevil is 

 frequently found feeding on the tips of the branches of the 

 cotton plant. They are nearly always to be found in pairs 

 and may easily be dislodged by shaking the plant, whea 

 they may be killed. 



During the year it was observed that a Thysanopterous 

 in.sect (thrips) attacked very young Hower buds and caused 

 them to drop. 



I'KSTS Ol' SWI;ET r-OTATOKS .\M> OK 1NDI.\N COKN. 



The scarabee or Jacobs {Cryptorhynchns hatatae} 

 attacks potatoes in all parts of the islaud. On this account 

 it is recommended that this crop should not be planted on 

 the same land at .shorter intervals than two or three years. 



Indian corn was seriously attacked by the corn ear 

 worm and the corn fly or leafhopper {Du)aiiotropis[De\^\i^x\ 

 viaidis). The Barbados varieties suffered less froni the 

 attacks c>f both these pests than any of the others under trial. 



