10 



THE AGRICULTURAL NEWS. 



January 8, 1910. 



INSECT NOTES. 



INSECT PESTS IN 1909. 



It has not been the custom to issue an annual 

 report on insect pests in the West Indies, and on the 

 entomological work of the Imperial Department of 

 Agriculture. It may be of interest, however, briefly to 

 summarize the more serious occurrences of pests during 

 the past year. 



OF SUGAE-CANE. No serlous attacks of sugar-cane 

 pests Lave been reported^in the Lesser Antilles during the 

 year, except the occurrence of the root borer {Diapvexjes 

 abhreviatus) over a compiaratively small area in Barbados, 

 ■which may be regarded as important. The district in 

 which the root borer attack is being experienced has suti'ered 

 severely from drought for several years, and planters seem to 

 think that the present attack is more severe in consequence. 



The attack first becomes ajiparent in the head row of 

 the fields, seemingly without regard to the windward or 

 leeward aspects. When it becomes obvious that the stool is 

 attacked, the canes are already in a dying condition and 

 beyond recovery. As has already been stated, the affected 

 stools in the head rows die first, and those further in the fields 

 later. The attack, in several instances, has begun on the 

 side next to where cotton was grown last season. This may 

 be accounted for by the fact that the adult weevil some- 

 times feeds on the leaves of cotton. The remedial measures 

 which are being put into force include the digging out of 

 the infested stools, and forking and liming the hole in order 

 to kill any grubs that may have been left in the ground 

 when the stools were tdken out. The stumps which are 

 removed are taken to a rocky spot in a pasture, and stacked 

 or bedded. After each load has been thrown on to the stack, 

 a dressing of lime is broadcasted over the surface. Many 

 grubs will be carried with the stumps, but it is expected 

 that ants, birds, lizards and toads will capture such a large 

 proportion of them that very few, if any, will survive and 

 get back to the same field to provide for another generation 

 of root borers. Experiments with vaporite and carbon bisul- 

 phide have been planned, and will be carried out. An 

 interesting and valuable paper on the root borer appeared in 

 the West Indian Bulletin, Vol. IV, p. 37. 



In British Guiana, the larger moth borer {C'astnia liens) 

 has again been reported. In 1901-5, this pest was stated 

 to be doing damage at plantation Enmore, and it now 

 appears to have spread to other estates in the vicinity. Many 

 remedies have been tried, including several recommended by 

 the Imperial Department of Agriculture, but none of them 

 seem to have been entirely successful. The practice most 

 generally adopted is that of catching the adult insect with nets. 

 The adult is a large, day-flying moth, measuring .3 inches 

 across the wings. The caterpillars tunnel lengthwise through 

 the cane for some 24 to 30 inches above ground, and through 

 the underground portions of the stool, so that, in addition to 

 causing a direct loss of a large amount of sugar, the insect 

 makes it impossible to grow ratoons. 



OF COTTON. During the season 1908-9, the cotton 

 worm {Aletiix eirgillaeea) was very abundant, and cotton- 

 growers were obliged to use large quantities of Paris green. 

 During the present season 1909-10, very little trouble has 

 been experienced with this pest in any of the cotton-growing 

 islands, and the expenditure for Paris green has been reduced 

 to a minimum. No setious trouble seems to have been 

 caused by the flower bud maggot or the leaf-blister mite. 



OF LIMES. Scale insects continued to attack limes, but 

 no severe outbreak has occurred during the year. The study 

 of the natural enemies of scale insects has been carried on, 

 large amounts of material having been collected and forward- 

 ed to the Head Office. From examination of this material, 

 it has been found that parasitic fungi are abundant, and 

 are probably very useful in keeping certain species (perhaps 

 all) of .sale insect}; in check. Insect parasites of scales are 

 also present in several of the islands, and they assist as well 

 in keeping this pest under control. 



OF ORAXOES. In 1907-8 and 1908-9, a small caterpillar 

 was reported from one estate in Dominica as attacking 

 oranges, and it was stated that the pest seemed likely to 

 become seriously important. The insect has not made its 

 appearance during the present season (1909-10), and it is to 

 be hoped that its natural enemies have assumed control of it. 

 OF GUAVAS. It has been suggested that the fruit fly, 

 or guava maggot, of Dominica attacks oranges as well as 

 guavas. The maggots of this fly were found in guavas 

 shipped to Bermuda, and were identified as Anastrepha 

 acidusa. (See Ar/ricultural Neips, Vol. VIII, p. 93.) In 

 October 1908, the Curator of the Dominica Botanic Station 

 forwarded to the Head Office a crate of oranges, guavas, and 

 mangos, which were suspected of being infested by the fruit 

 fly. From the guavas, a number of specimens of Anastrepha, 

 probably A. aeidnsa, were reared, but none could be obtained 

 from the oranges ; or from the mangos. Another crate of 

 oranges forwarded in November gave the same results. The 

 present situation is this: guavas are attacked by a fruit fly, 

 Anastrepha aeidnsa, in Dominica. Oranges are often injured 

 in such away that, they rot, and many are lost in this manner, 

 but so far, no fruit fly has been proved to be the cause of 

 the injury. 



OF CACAO. During the past year, no reports have been 

 received of serious insect attacks on cacao. A beetle appear- 

 ed in St. Vincent, and caused a certain amount of injury to 

 the leaves of young plants, but did not assume the aspect of 

 a serious pest. 



OF SWEET poTATos. The scarabce, or Jacobs, of the sweet 

 potato {Cri/pjtorlii/nchus hatatae) has been a very serious pest 

 in Barbados during the past season. A series of experiments 

 that was carried out gave no definite results, and another 

 one has been started, which will be completed during 1910. 



OF CORN. Toward the end of 1908, it was reported 

 from Nevis that the varieties of Sorghum which produce the 

 grain in den.se heads were attacked bj' the larva of a small 

 moth which lives at this stage among the ripening grain. 

 This is not an easy pest to control, for there is some difficulty 

 in getting any arsenical poison a sufficient distance into the 

 head of developing grains to kill the small caterpillar, and as 

 the damage is done before the grain is ripe, nothing can be 

 gained by cutting the crop early. 



In addition to the Insect Notes which have appeared in 

 each number of the Ai/ricultural JVen.-s, the following papers 

 dealing with the insects in the West Indies have been issued 

 during the year:— 



The Aleyrodidae of Barbados, West Indian Bulletin, 

 Vol. IX, p. 345. 



Millions and Mosquitos, West Indian Bulletin, Vol. IX, 

 p. 3S2. 



The Flower Bud Maggot of Cotton, West Indian Btdletiri, 

 Vol. X, p. 1. 



The Scarabee of the Sweet Potato, West Indian Bulletin, 

 Vol. X, p. 180. 



Millions and Mosquitos, Pamphlet Series, No. 55. 



Insect Pests of Cacao, Pamphlet Series, No. 58. 



