376 



Insect and Fungus Pests. 



[JULY, 



generally, apart from the south-west, such conditions only 

 obtain occasionally, and usually for a limited period. Hence 

 farmers and others often take the risk of weather conditions 

 being favourable, and refrain from spraying. In connection 

 with potato spraying it should be noted that severe foliage 

 injury has occurred where potatoes badly attacked by aphides 

 liave been sprayed with copper fungicides. Under such con- 

 ditions, especially in the drier districts, it is perhaps wiser 

 not to spray. 



Particulars as to the making of these spraying mixtures 

 and precautions that should be taken are stated in the 

 Ministry's Leaflet No. 23. 



Most of the potato diseases will now be in evidence, and growers 

 lifting first earlies may find potatoes with warts or protuberances 

 upon them. This is, most probably, the dreaded Wart Disease 

 (Figs. I and 2), which, if present, should be at once notified to the 

 Ministry or to the local police. The appearance of the disease 

 is unmistakable (see Leaflet 105), although sometimes a bad 

 attack of " ordinary scab " is liable to be confused with it. 

 This " ordinary scab " is merely a surface disease, and has 

 little effect on the crop beyond spoiling its appearance. 



Leaf Curl is another disease which very seriously reduces 

 the yield of the potato crop. Curled plants may be recognised 

 by their dwarf appearance and the fact that the lower leaves 

 are markedly curled. The produce of such plants is always 

 below the normal, and in bad cases the crop is almost nil. The 

 iiubers from these plants, being of small size and of normal 

 appearance, are apt to be set aside for " seed." To do this, 

 however, is a great mistake, as tubers from curled plants yield 

 a curled crop again, with an increasingly low yield. If home- 

 saved seed is required the healthiest plants should always be 

 selected for " seed," and if curl is at all prevalent, no " seed " 

 should be saved from the plot. In dry and southern districts 

 fresh northern seed should be obtained each year. (See new 

 edition of Leaflet No. 164, and article in the issue of this Journal 

 for last month, p* 287.) 



Pests on other vegetables will be plentiful and the various 

 caterpillars of the Cabbage Butterflies and Cabbage Moth 

 will be attacking the Brassicas. In gardens and small 

 plots much can be done when the butterflies are noticed by 

 turning over the leaves and crushing between the thum^b 

 and finger of the gloved hand any batches of eggs which may 

 b : seen, or, if the eggs have hatched, by noting the small 



