GARDEN NOTES.

Wairarapa Daily Times, 21 December 1927, Page 3

GARDEN NOTES.

INSECT PESTS OF THE ROSE. Aphides. Perhaps the worst, because they multiply with surprising rapidity, are the greenflies or aphides. The Rose aphis attacks all young twigs and leaves, and, apart from the unsightly appearance of the branches, does extensive damage l>y sucking nutritive sap from (lie bush and by closing the breathing' pores of the leaves with its gummy excreta. These plant lice are too well known to require description; they usually congregate in dense colonies on the green shoots. Spraying with a good insecticide is a satisfactory course to adopt. Almost any of the nicotine preparations can be used effectively. Sawflies. Far more destructive than the aphides is a largo family of pests called the sawflies (Tcnthredinideac). Many species are found in rose gardens; they are all armed with a saw-like contrivance with which they cut up, cat or destroy the leaves, and in some cases the soft herbaceous twigs produced by a healthy plant. The yellow larva of one of the sawflies (Poecilosoma candidatum) voraciously devours th ■ young foliage, and, as soon as its appetite is appeased, bores into the soft pith of the branches and causes them to wither and die. When this sign of its presence is perceived, cut off each twig which contains the grul) and burn it. Other sawflies, the Hylotomac, are leaf-eaters. Ilvlotoma rosac is a small fly of dirty yellow colour and having a black head and thorax; the larva, or grub, is green, with yellow and black spots, and is hatched from the egg in a few days. It destroys many), of the leaves and before it arrives at the pupal or quiescent state spoils the elegant appearance ol: the foliage; it pupates in the ground. Another sawj]y, Ericampa rosac, is black, about I-Sin. long, and some of its legs are spotted with white. The larvae are twice that size, and light green in colour, with orange-coloured heads. This grub eats the upper surface of the leaves, causes them to die, and then they fall off; when satiated, the larva passes into the soil and spins a cocoon underground. In some districts these larvae are very numerous and are known as Rose slugs. Occasionally the edge of the leaf is noticed rolled up; or folded neatly over; this is the retreat of the grub of Blcmnocampa pusilla, another black, small sawfly, w ith brown, tinted wings. The grub is short, stout, bristly, and green, with yellow or brown head. Damage is done by it in two ways; it cats the foliage and prevents the leaves performing their natural functions by rolling them up. The tiny, spotted green grub, which lies curled up on the under surface of the leaves, is from another destructive sawfly-, Emphytus einctus. That which makes a nest of small pieces of leaves is Lyda inanita, and the holes, to all appearances torn in the leaves, are due to a species called Cladius. Many others may be found in gardens, and they do much damage if loft unchecked; in all cases from two to six; generations are produced in one season. Before dealing with these destructive pests the gardener must know something of their habits. The fly lays her eggs on the branches and foliage; when the eggs hatch out the larvae immediately start to feed on the foliage, and when they become surfeited they pass the quiescent state underground, or else they burrow into the stems or midribs of the loaves. Those that have found lodgings on or in branches will be destroyed at pruning time provided the primings are gathered up and burned, as they should be. Spraying with arsenate of lead during the growing season will poison many.