453 



Miller (D.). Pests and Diseases of New Zealand Flax. — JJ. Agric., 

 Wellington, N.Z., xiv, no. 6, 20th June 1917, pp. 431-439, 2 figs. 



The flax-grabs which damage the leaf and fibre of New Zealand flax 

 {Phormiiim tenax) were the subject of investigation during 1916. Tne 

 most prevalent and most injurious are : Xanthorhoe praefedaia. Walk., 

 the larvae of which attack the lower surface of the leaves, causing 

 them to decay [see this Review, Ser. A, iii, p. 302]. If during a flood 

 the water does not cover the flax-bushes or completely immerse the 

 leaf -tubes, the larvae will still shelter in the unsubmerged portions or 

 hang suspended among the fohage, and unless the head be submerged, 

 seem indifferent to the water. If floated, however, they soon drown. 

 Colonies of this species will migrate from place to place. The larvae 

 first appear in early August and increase during the following months, 

 disappearing at the end of December, when they hibernate in the 

 leaf-tubes. Young and old may be found attacking the same patch 

 of flax, indicating that they hatch at different periods. The species 

 occurs throughout New Zealand. 



Melanchra steropaslis, Meyr., is found throughout the Dominion, but 

 is most abundant in Southland. In creneral habits it resembles 

 Xanthorhoe, but attacks the leaf differently, cutting notches in the 

 edges. This species is found in both moist and dry localities practically 

 throughout the year. 



The larv^a of the Psychid, O^cetims omnivorus, Fereday, is found 

 throughout New Zealand and is active most of the year, but is not 

 as yet of much economic importance. 



The attacks of these grabs are of but slight importance in locaUties 

 that are regularly flooded and where leaf-tube accumulations are not 

 abundant, these two features being as a rule correlated. This has led 

 to the use of artificial flooding as a control. Dead leaf-tubes should 

 be regularly removed. Both these measures improve the quality of the 

 flax quite apart from the question of grub attacks, which are said to 

 be responsible for a loss amounting to £4 10s. per ton of fibre. A 

 feasible method of applying moisture or of flooding would be by 

 means of artesian wells, which have already been sunk in various 

 parts of the swamps. The application of parasitic insects will be one 

 of the most important methods of controlling the grubs. Ichneumonids 

 are the most prevalent of these, about 67 species being recorded in 

 New Zealand. Xanthorhoe praefectata has also been found parasitised 

 by the fly Syrphus ortas. Insectivorous birds are an important check 

 in the bush areas, but do not penetrate far into the swamps. 



Several scale-insects infest flax-leaves, among them being 

 Poliaspis media, which is sometimes present in great numbers. 



DiAKONovA [Mme E). Ki> Bonpocy o pacnpocipaHeHiM MycKapflUHW 

 Bis /loHCKOil oQjiaCTM. [On the Question of the Spread of 

 Muscardine in the Province of Don.]— « B-feCTHMKTj CanoBOACTBa, 

 riJlOAOBOACTBa M OropOAHMMeCTBa.» {Herald of Horticulture, 

 Fruit-Growing and Market-Gardening'], Petrograd, Ivii, no. 11-12, 

 November-December 1916, pp. 369-386, [Received 31st August 

 1917.] 

 A general account of muscardine fungus in silkworms is given, with 



the results of some experiments carried out by the author in the 



