. Better fruit. Fruit-culture. *. R a BRa r ASHLAND,OHIO. P_i<^-^r*^?'*'ASHLAND PUMP AND HAY TOOLWORKS i 'Vnj'^n /''"^ I 20 PRANCE STREET \ r J-1 How Spray Kills By Dr. A. , Entomologist, Head of Department of Zoology. Washington State College. SPRAYS that are used to control in- do not all work alike. containing arsenicals must be calcn by the insect in order to destroy. Others, like oil emulsions, tobacco and sulphur-lime, kill when in contact with the insect's body, by a process of sutTo- cation. Some sprays have a disagree- able taste and prove effec
. Better fruit. Fruit-culture. *. R a BRa r ASHLAND,OHIO. P_i<^-^r*^?'*'ASHLAND PUMP AND HAY TOOLWORKS i 'Vnj'^n /''"^ I 20 PRANCE STREET \ r J-1 How Spray Kills By Dr. A. , Entomologist, Head of Department of Zoology. Washington State College. SPRAYS that are used to control in- do not all work alike. containing arsenicals must be calcn by the insect in order to destroy. Others, like oil emulsions, tobacco and sulphur-lime, kill when in contact with the insect's body, by a process of sutTo- cation. Some sprays have a disagree- able taste and prove effective as a re- pellant, rather than as a poison, the insects going hungry rather than to eat the had-tasting spray. It is the repellant action of sprays that is little understood, much neglected, but never- theless most important. Bordeaux spray, sulphur-lime, tobacco, oil emul- sions, soaps and lime, our commonest spray materials, are all repellants to chewing insects. This should he borne in mind when compounding mixtures of several sprays. It is not alone the chemical I'caction that nuist be heeded in combining sprays, nor also the pos- sibility of foliage injury, but the physiological reaction on the insect must be considered as well. A newly- hatched codling worm is a delicate little creature. It has a selective appe- tite and does prefer to feed within the pulpy calyx end instead of on the tough skin of tlie apple. If its first meal is distasteful, the young codling worm has been seen to reject it, working the nibblings out of its mouth by a secre- tion of silk. This is jirobably always the case where the apple is heavily coated with arsenate of lead, or wliere lime, bordeaux spray or sulphur-lime have been added to the |H)ison. Thus it is that late siJiayings lack effective- ness, even when the fruit is whitened by the spray. Most of the entering worms to swallow some of the poison, however, enough to kill them after a few days, but in the meantime the apple is &q
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