Pests and Diseases 



Contact washes must be applied with special 

 syringes or machines which are capable of conveying 

 the wash to the plants with great force, and it will 

 be found that such washes are only effective when 

 applied in this manner. The sticky substance 

 which exudes from aphides renders them almost 

 impervious to a light spraying, but it is a fact that 

 the soft body of an aphis may be smashed by a jet 

 of plain water applied with force behind it. 



(b) Biting insects, such as leaf-eating caterpillars. 

 In this case a poisonous wash must be used, and force 

 is not necessary ; in fact, the wash should bs applied 

 in a fine condition as lightly as possible, so that it 

 remains on the leaves. Arsenate of lead, Paris green, 

 and London purple are all used for the caterpillars 

 of the Winter Moth (4), Lackey Moth (69), and 

 similar pests. The first-named gives good results. 



Of some species in this group the female moths are 

 wingless, and, as they must climb the trees to deposit 

 their eggs, they may be trapped by means of grease 

 bands placed around the tree trunks. (See page 44.) 



(c) Weevils such as vine, plum, hop, and rasp- 

 berry weevils (2) are often very troublesome and, 

 when numerous, they are not easily g3t rid of. 

 Trapping is practically the only remedy in this 

 case. Tarred boards are used at night time for 

 these weevils. For Apple Blossom Weevil see 

 B. of A. Leaflet 15. Earwigs must also be included 

 in this section, for these insects can only be kept in 

 check by means of traps, such as the simple device 

 which is adopted by dahlia growers, who place a 

 small flower-pot containing hay upside down on the 

 top of the stakes which support the plants. 



(d) BORING INSECTS. The Pith Moth (90), which 



69 



