106 



THE AGRICDLTURAL NEWS, 



March 30, 1912. 



INSECT NOTES. 



THE COTTON LEAF-BLISTER MITE IN 

 BARBADOS. 



With further reference to the occurrenne of leaf blister 

 mite on cotton in Barbados, which was briefly mentioned in 

 the last number of the Agricultural N'ews (see Vol. XI, p. 90), 

 the following note may be of interest. 



The existence of the leaf-blister mite in Barbados was 

 first discovered by the Entomologist on the Staff of the 

 Imperial Department of Agriculture, on February 27, 1912, 

 and reported to the Colonial Secretary on the same day. The 

 matter was referred to the Local Department of Agriculture 

 which has since been investigating the extent of the attack, 

 and advising cotton growers to pull up and destroy the cotton 

 in all infested fields. 



The field in which the pest was first found is part of an 

 estate adjoining Bridgetown, on the south. This estate form- 

 erly produced a considerable amount of cotton, sugar and 

 other products; but in recent years has been more and more 

 given up to tenantry. The field in question is in close 

 proximity to a large number of small houses, each with its 

 tiwn plot of ground. 



Investigation by the Officers of the Local Department of 

 Agriculture has so far shown the infested area to include 

 a strip some two or three miles wide, along the westward coast 

 for a distance of 18 miles, the .southern limit apparently 

 being about 4 miles south-east of Bridgetown. 



It will be seen that by far the greatest amount of infes- 

 tation occurs to the north of Bridgetown, where the frequency 

 of the occurrence of the pest and the severity of the attacks 

 indicate that fields in this section have been infested for 

 a longer time than the field where it was first discovered. 



The Governor of Barbados has appointed a Committee in 

 connexion with the occurrence of leaf-blister mite, which is 

 asked to consider and report upon the following points: — 



(a) what steps should be taken to stamp out the 

 existing disease, 



(b) whether legislation is needed, 



(c) the area infected. 



This Committee, which consists of ten members of the 

 Agricultural Society, together with the Superintendent of 

 Agriculture of Barbados and the Entomologist on the Staff 

 of the Imperial Department, held a meeting on March 26. 

 As has been stated already, however, the Officers of the Local 

 Department had investigated the extent of the infestation, and 

 were recommending that infested cotton .should be pulled up 

 and burned. 



Notice of a bill was given in the House of Assembly on 

 Tuesday, March 26, providing for compulsory destruction 

 of cotton infested with leaf-blister mite: for, although 

 owners and managers, generally, have readily complied when 

 requested to destroy infested cotton, it has happened occa- 

 sionally that this request has been refused. 



The life-history of the cotton leaf-blister mite is not 

 known, nor have any food plants of this pest ever been dis- 

 covered except cotton, both wild and cultivated. 



In those islands of the West Indies where the leaf-blister 

 mite has been a pest for several years, it has been found 

 necessary to develop a strain of cotton which will yield its 

 crop in one picking, whereas in Barbados it is the custom to 

 get a second or even a third picking, allowing the cotton to 

 occupy the fields for twelve months, or more. It will prob- 

 ably be necessary in Barbados to adopt a course similar to 



that followed in ike other islands, if the leaf-blister mite 

 becomes established and assumes serious proportions. 



The control of the leaf-blister mite depends upon the 

 destruction of all old cotton as soon as the crop is finished. 

 If an interval of several weeks ensues between this and the 

 planting of the new, and attention is paid to the destruction 

 of all infested leaves as they first appear on the cotton plants, 

 the attacks of leaf-blister mite seldom seriously affect the 

 yield of cotton. 



The fact that in Barbados there is very little wild land 

 and bush, and that the cultivated fields are very carefully 

 weeded and tilled, would indicate that in that island the diffi- 

 culties of control would be less than in those where cultiva- 

 tion is not maintained at such a high point and where there 

 is a greater abundance of uncultivated and bush-covered 

 land. 



MANGO PESTS IN THE PHILIPPINES. 



A short article in the Philippine Agricultural Revieio 

 for June 1911 (Vol. IV, No. 6) gives an account of the 

 occurrence of insect pests on mangoes, which had appeared 

 in the Philippine Islands in such numbers as to cause 

 a considerable amount of loss. 



One of these pests was a small insect, with sucking 

 mouth parts, belonging to the Hemiptera Homoptera, and 

 related to such insects as cane Hies and leaf-hoppers. Atten- 

 tion was attracted to this pest through the failure of mango 

 trees in several localities to set their fruit. Investigations 

 showed that the trees which failed to set fruit were generally 

 covered with a black blight, and it was found that the 

 larvae of these sucking insects were injuring the buds and 

 tender stems to such an extent as to cause the flowers to 

 drop, and thus prevent the development of fruit. 



It was considered by Mr. P. J. Wester, Horticulturist of 

 the Board of Agriculture, that the insect was identical with 

 the so-called mango fly in India, under which common name, 

 by the way, are included three species of homopterous insects 

 (Idiocerus niveosparsus, Leth., /. atkinsonii, Leth., and 

 /. clypealis, Leth.), which in certain years has been reported 

 to reduce the mango crop in that country to one-third of its 

 normal amount. Two of these species have been identified 

 at Washington, D.C., from specimens captured in the Philip- 

 pines. These are Idiocenis clypealis, Leth., and /. niveos- 

 parsus, Leth. 



Another pest mentioned as being quite destructive to 

 mango bloom in the Philippines is the: ' caterpillar that enters 

 the central stem of the flower panicle and hollows it out, 

 causing it to shrivel up and die.' 



In the December number of the same journal Mr. Wester 

 reports the occurrence of another mango pest. This is one 

 of the fruit flies, which is said to be either identical with, or 

 very nearly related to, Dacus ferruginous, which is destiuctive 

 to mangoes in .Java and parts of Malaysia; it is thus also 

 related to Trypeta ludens, which is a serious pest in Mexico, 

 attacking mango, orange and guava. 



These pests have not been recorded from the West Indies, 

 but it may be well for the planters in these islands to realize 

 that serious pests occur in other localities. 



The harmful nature of the mango weevil (Agricultural 

 News, Vol. X, p. 282), of fruit flies (Agricultural News, 

 Vol. VIII, p. 93), and of other pests has been recorded, as 

 is shown, in previous numbers of this journal, and attention 

 is directed to these newly discovered pests in order that West 

 Indian planters may take all reasonable precautions to pre- 

 vent the introduction of any of them. 



