284 



STATE HORTICULTURAL SOCIETY. 



The second class of insects, those that feed by sucking, are not so 

 numerous, but are more difficult to control. The arsenites have no efPect 



on this class of insects. Let us watch a familiar 

 example, the mosquito, that we may see why the 

 arsenites do not affect it. When the mosquito 

 alights on the hand, it presses its pointed beak 

 close to the skin and then runs down a set of hair- 

 like needles inside of this hollow beak and these 

 pierce the skin. Then, without changing the beak, 

 the blood is drawn through it from the puncture 

 to the stomach. Even if the hand were covered 

 with Paris green, the mosquito would not get a 

 particle of the poison in sucking the blood, as 

 the two are entirely separate. The conditions 

 are the same with a large number of flies, to which 

 order the mosquito belongs, and with the whole 

 order of bugs, such as the brown squash bug, 

 yellow lined currant bug, bed bug, lice on stock, 

 plant lice, and scale lice. The head and beak of 

 a plant bug are shown in the accompanying cut 

 Fig. 3.-Head Md Beak of Plant (Fig. 3), with the needle-like parts drawn from 

 ^^' the tube. 



We now see why it is that some other insecticide besides the arsenites 

 must be used to kill these insects. They must be killed by bringing some 

 substance in contact with them, and many of our remedies, such as kero- 

 sene emulsion, hot water, carbolic acid emulsion, whale oil soap, and 

 pyrethrum are our only means of protection. The kerosene and carbolic 

 emulsions are especially useful as they are very penetrating. All of this 

 last list of remedies must come in direct contact with the insect to affect 

 it, and this is one great reason why these remedies are so ofte^n reported a 

 failure. 



FUNGOUS DISEASES OP THE APPLE. 



APPLE SCAB (Fusicladium dendriticum. Fckl.) 



This is one of the most destructive diseases of the apple, as it attacks 

 both foliage and fruit, and, although it is more injurious to some varieties 

 and in some seasons, than others, it seldom fails to show itself to some 

 extent. It is generally called " apple-scab," but in some sections it is 

 known as the "black-spot" upon the fruit, and leaf blight and sometimes 

 leaf mildew when upon the foliage. 



It generally shows itself first upon the foliage as small, olive green, 

 velvety spots. These enlarge and several may run together and thus 

 involve a large portion of the leaf. Although most common upon the 

 upper surface, they are often found, when the attack is severe, upon the 

 under side, and may even extend to the leaf stem and the young shoots. 

 The tissues attacked are destroyed and soon turn brown and dry up; 

 when upon the leaf the discolored portion drops out, and in severe cases 

 the entire leaf falls. 



