123 



The complete life-history of this Chalcid is being worked out, and 

 an endeavour is being made to find some parasite by means of which 

 its numbers may be reduced. In Tasmania and Australia, whence 

 it probably comes, it has apparently passed unnoticed, perhaps 

 owing to the activities of natural enemies. The gnarled appearance 

 of the bark of blue-gums caused by it has frequently been attributed 

 to the gum-tree Coccid, Eriococcus coriaccus, Mask., and figures are 

 given showing the distinction between the two types of injury. 



Atkinson (E. H.). Phormium tenax. Diseases and Insect Pests. — 

 N.Z. Jl. Agric, Wellington, xxiii, no. 5, 21 November 1921, 

 pp. 298-302. 



There are many insect pests of Phormium tenax (flax) in New Zealand, 

 all of which are indigenous, but it was not until the early years of the 

 present century, when the draining of swamps placed this plant among 

 the principal agricultural crops of the country, that their depredations 

 were of serious importance. The three chief pests are the larvae of 

 the moths, Xantliorhoe praefectata, Wlk., Melanchra steropastis, Meyr., 

 and Oeceticus omnivorns, Fereday. The first named, which is the most 

 important pest, has been dealt with at length in previous papers 

 [R.A.E., A, vii, 82]. M. steropastis attacks the edges of the leaves, 

 and the larvae shelter in the dead leaf-tubes. Pupation occurs usually 

 in the ground, though pupae have been found in the rolled-up leaves. 

 0. omnivorns is a widely distributed and well-known Psychid moth, 

 its conspicuous bags hanging from the leaves or stems of a variety 

 of plants. The larvae are active most of the year, and eat large 

 patches from the lower surface of the leaf, sometimes extending 

 through to the upper surface, and making more or less circular 

 holes in the blades. Besides parasites, these larvae are attacked by 

 predators, including larvae of the hover-fly, Syrphus ortas, and 

 insectivorous birds. 



Departmental Activities. — //. Dept. Agric. Union S. Africa, Pretoria, 

 in, no. 6, December 1921, pp. 494-496. 



^Amiraphis persicae-niger (black peach aphis) and Myzus persicae 

 (green peach aphis) are troublesome in the high veld every spring, 

 but were so numerous in 1921 that many peach trees bore no fruit and 

 were practically defoliated. The new shoots appear stunted, and the 

 leaves are small, curled and deformed. The two species frequently 

 occur together. Phmis and apricots were infested to a less extent. 

 A. persicae-niger lives through the entire year on peach ; M. persicae 

 winters' on cabbage and similar plants and migrates back to peach 

 in early spring. Very hot weather or drenching rain are both very 

 eflficient checks on the numbers of these Aphids. Enemies include 

 Coccinellids, larvae of Syrphid flies, and internal parasites. The 

 Aphids, however, multiply rapidly at temperatures several degrees 

 below that necessary to their insect enemies, and spraying is therefore 

 essential. A . persicae-niger can be controlled by spraying before any 

 foliage appears, thus killing the colonies present, but spraying for 

 ^1/. persicae must be done after the new growth starts, but as soon 

 as the attack begins and before the leaves become distorted, otherwise 

 the insects can shelter within the curled foliage. The standard spray 

 mixture is 1 part tobacco extract sheep dip to 8 parts water, with 

 about 1 lb. soap to 20 gals, of the spray. 



(5733) r 2 



