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THE IRRIGATION AGE. 



The Necessity of Spraying 



BY 

 HOWARD EVARTS WEED 



When we figure out the annual money value of any 

 special agricultural crop, we obtain some surprising figures. 

 If we then add 20 per cent to these figures as representing the 

 annual loss through the work of the injurious insects and 

 fungous diseases the loss is really greater than this on the 

 average we get some idea of the great loss to agriculture 

 caused by the work of insects and fungi. We then have our 

 eyes opened to the necessity of such a "small" matter as 

 fighting insects and fungous disease. 



Generally speaking, spraying with various insecticides and 

 fungicides is the best means of preventing loss by these ene- 

 mies to agriculture. But there is no work on the farm where 

 attention to detail is more necessary than in spraying opera- 

 tions. To accomplish results, the spraying must be applied at 

 just the right time and with the right chemicals used in 

 correct proportions. Otherwise our work is mostly useless, 

 which is always discouraging, for we are all after results. 

 After all, we make a success or failure of life largely in propor- 

 tion to the attention we give to the small things of life to the 

 little details and attention to detail in spraying is certainly no 

 exception to the rule. But of more importance than anything 

 else is spraying in time. There is practically no use in the 

 application of a fungicide to a plant after we notice that plant 



Apples are wormy because a small moth lays its eggs in 

 June on the blossom end of the forming apples at about tlje 

 time the blossoms fall. These tiny eggs hatch into small 

 worms which eat into the fruit. In three or four weeks the 

 worms have become full grown and come out of the apples 

 and "pupate" or pass into a resting stage either upon the 

 tree, in crevices or under pieces of bark. Then in another 

 ten days they hatch into the moths, which lay the eggs for 

 a second brood. The winter is passed mostly in the pupa 

 state. Did you ever find the little cocoons of silk with the 

 pupa within them along the sides of apple barrels early 

 in the spring? Well, the coming spring look the barrels 

 over and see that these cocoons are destroyed, for it will mean 

 that many less moths to lay their eggs on your apples next 

 summer. The fact is you had better stop reading this article 

 and look over those apple barrels right now. 



Now then for the remedy for wormy apples. If the apple 

 trees are thoroughly sprayed just after the blossoms have 

 fallen with Paris green or the arsenate of lead, just zf little 

 portion of the poison will be placed on the blossom end of the 

 forming apples at about the time the eggs of the first brood 

 are hatching, and the worms will be killed by eating of the 

 poison. We thus see the importance of placing a little of the 

 poison on each forming apple, for if the spraying was not 

 thoroughly done it would just "happen" that we missed just 

 the places where the young worms are hatching. In former 

 years Paris green was used in spraying fruit trees, but now 

 it is found that arsenate of lead is much better and we get 

 better results in every way. So that Paris green is a back 

 number now. I shall not stop to explain why, but would 



Fig. III. 



Fig. II. 



disease is present. Fungicides are preventives and not rem- 

 edies and their application must be made long before the in- 

 dications of disease are present. But when we find disease 

 present, we should prepare for the spraying so as to ward off 

 the disease the following year. Then again with insects, we 

 will have to keep a close watch for them and apply the rem- 

 edy just as soon as we notice the insects upon the plants, for 

 it only takes a few days for a lot of insects to destroy a crop. 

 But while every farmer should thoroughly understand the 

 subject of practical entomology and mycology, it is not neces- 

 sary that one should study these subjects from the scientific 

 side. All we want to know is how to prevent loss, and in 

 order to know this it is only necessary that we know a few 

 general principles as to why we apply the fungicides at all, 

 and why and how we use certain insecticides for certain 

 insects. So in order to consider the subject properly, let us 

 take two insects and one plant disease attacking the apple to 

 serve as examples of the whple subject. We will thus con- 

 sider the Apple Worm, the San Jose Scale and Apple Scab. 



refer you to that last bulletin from your Experiment Station 

 which told all about it. By the way, what did you do with 

 that bulletin? 



The various stages of the Apple Worm are shown in 

 Fig. 1. In this insect we have a case where the insect eats 

 fruit or foliage and we kill such an insect with a substance 

 which acts as a poison when eaten. In fighting insects we 

 should know how food is taken, for then when we find an in- 

 sect that eats foliage we can kill it by means of a poison 

 applied to its food plant. This is a general principle which 

 should be remembered. 



Now let us take the well known San Jose scale, shown in 

 Fig. 2, as an example of how insects should be killed which 

 suck their food. In these insects the mouth parts are formed 

 into a beak through which the plant juices are sucked. There 

 has been so much said and writte nregarding the San Jose 

 scale for ten years past that one would think that every 

 farmer would know all about it by this time. Yet when 

 we find an apple with some little red spots upon the skin 



