302 



Cockayne (A. H.). The flax-grub. — Jl. Agric, Wellington, N.Z., x,. 

 no. 1, 20th January 1915, pp. 1-7, 5 figs. 



' Phormium flax is one of the most important of the secondary rural 

 products of New Zealand. Though the total value of the 65,000 acres 

 growing it . and of the machinery necessary for extracting the fibre 

 is only about £1,750,000, the annual value of the fibre crop exceeds 

 £600,000. The most serious injury to flax swamps is due to the " flax- 

 grub." Until quite recently it was thought that the native slug, 

 Athoracophorus [Janella) bitentaculatus, was the agent concerned, and 

 in the annual report of the Department of Agriculture for 1909, 

 T. W. Kirk and the author definitely stated this to be the fact. During 

 the past summer the author has been able to ascertain that this is 

 not the case. Larvae taken from freshly injured flax were bred out, 

 and the Geometrid moth, XanfJiorhoe praefectata, emerged in mid- 

 November. Until they pupated, the larvae were fed on flax leaves 

 and produced the typical injuries that had previously been attributed 

 to the slug. A large number of adult Athoracophorus, as well as eggs, 

 were collected. In no case did they injure fresh flax leaves, and on 

 hatching, the young slugs throve well on quite rotten leaves, indicating 

 that they normally feed on the decaying herbage that is found in large 

 quantities at the bases of the flax plants. Xanthorhoe praefectata was, 

 until quite recently, regarded as a comparatively rare insect. It has 

 apparently increased enormously of late years in flax swamps, owing 

 probably to draining and the setting up of favourable conditions. 

 Diseased leaf is comparatively absent in swamps that become flooded 

 periodically. The almost total destruction of the insect-eating water- 

 fowl and swamp-birds, formerly so abundant in the flax areas, has 

 probably aided the spread of the pest. There seem to be two periods 

 in the year when fresh injury is apparent — namely, in September, 

 October, and November, and again in March and April. This 

 would indicate that this species of Xanthorhoe is double-brooded, so 

 far as the southern end of North Island is concerned. It is at 

 present impossible to suggest any remedial measures likely to be of 

 practical value. 



Report on the Botanic and Experiment Stations, St. Kitts-Nevis, for the 

 Year ended March 31st 1914. — Agric. News, Barbados, xiv, no. 333, 

 30th January 1915, p. 39. 



St. Kitts was not very seriously affected by sugar-cane pests during 

 the year, though it appears that the grub of Exopihthalnms esuriens 

 is capable of inflicting a great deal of damage as a root-borer, and 

 immediate precautions should be taken against it. The termites, which 

 seriously attacked canes in one district some years ago, seem to have 

 been adequately controlled by the measures advised by the entomologist 

 of the Imperial Department of Agriculture. During this season 

 preventive measures have greatly lessened the damage done by the 

 cotton-worm. The leaf-bhster mite has been troublesome only in fields 

 in the neighbourhood of those on which old cotton plants have been 

 allowed to remain. 



