INSECTICIDES AND FUNGICIDES 



3002 



INSECTIVORA 



feed upon the tissues of the plants, biting or 

 gnawing them, and in consequence any poison- 

 ous substance placed on the plant is eaten by 

 them. Other insects, however, as the plant lice 

 and the scale insects, suck the sap of the plants 

 and thus cannot be poisoned in so simple a 

 manner. Indeed, some of these sucking in- 

 sects resist any treatment ever devised, and 

 are thus among the most dangerous of all 

 plant enemies. 



Of the "stomach poisons," which kill the bit- 

 ing or gnawing feeders, the most effective are 

 those containing arsenic, the two described be- 

 low being as valuable as any: 



Kedzie Mixture. To eight pounds of carbo- 

 nate of soda the common sal soda add two 

 pounds of white arsenic, and boil the whole in 

 two gallons of water until the arsenic is dis- 

 solved. This solution is poisonous in the ex- 

 treme, and should always be so labeled. When 

 it is to be used, one pint is added to forty 

 gallons of water, into which is also stirred two 

 pounds of lime, slaked. The mixture is then 

 sprayed upon the affected plants, but care 

 should be taken never to spray this or any 

 other poison upon lettuce or other salad plants, 

 or upon such plants as spinach, of which the 

 whole plant is eaten. 



Arsenic Solution. This differs very little 

 from the compound just described. Four 

 ounces of Paris green and two pounds of 

 slaked lime are dissolved in forty gallons of 

 water, and the resultant mixture is used as a 

 spray. In this solution may be soaked slices 

 of potato, which are then placed about the 

 roots of plants that cannot be sprayed. 



"Contact" Poisons. The sucking insects are 

 usually killed by what are known as "contact" 

 insecticides that is, by those which actually 

 affect the body of the insect, and not its food. 

 Either corrosive or suffocating substances are 

 most used, and sulphur and carbon disulphide 

 fumes play a large part. The most popular of 

 these contact insecticides, however, is kero- 

 sene, but since few growing plants can be 

 treated safely with pure kerosene, the follow- 

 ing mixture is commonly used: 



Kerosene Emulsion. Dissolve eight ounces 

 of hard soap in a gallon of boiling soft water, 

 and add two gallons of kerosene. Mix or churn 

 the whole, violently. When this is needed for 

 spraying it is diluted by the addition of from 

 twenty to forty gallons of water. 



Whale-oil soap is also an excellent insecti- 

 cide, one pound of the soap being dissolved 

 in from one to ten gallons of water. 



Fungicides, or Fungus-Killers. These, like 

 the insecticides, are sprayed \rpon growing 

 plants, but the spray must be finer, so that 

 no drops remain upon the leaves. Some are 

 especially adapted to the preservation of seeds 

 or of fruit. 



Bordeaux Mixture, the best fungicide for 

 general purposes, is made as follows: In a 

 wooden vessel dissolve five pounds of copper 

 sulphate (blue vitriol) in five gallons of water. 

 This can best be done by suspending the sul- 

 phate in a coarse cotton bag in the water. To 

 neutralize the corrosive power of the vitriol, 

 add a solution formed by slaking five pounds 

 of fresh lime in five gallons of water. Pour 

 this compound into fifty gallons of water and 

 mix violently. This solution is known as the 

 five-five-fifty, from its proportions. If plants 

 with very young leaves, or such delicate trees as 

 the peach and the plum, are to be sprayed with 

 this mixture, twenty-five gallons more of water 

 and an extra pound of lime should be added. 



Copper Sulphate Solution. This is a valu- 

 able mixture in which to soak the seeds of 

 barley, oats or wheat that are in danger of 

 fungus affection. It must not be used as a 

 spray, as it has a corrosive effect on the foliage. 

 To make it, simply dissolve one pound of cop- 

 per sulphate in two gallons of water. 



Copper Carbonate Solution. Some sprays, 

 including the Bordeaux mixture, will discolor, 

 and so may not be used on fruits, or on foliage 

 that must be kept green. The solution formed 

 by adding to ten gallons of water an ounce 

 of copper carbonate dissolved in a pint of 

 ammonia has no such fault. 



Sulphur. This simple fungicide is very useful 

 in the hothouse. It is sprinkled freely on the 

 steam pipes, or on some other surface warm 

 enough to vaporize it, and is usually effective 

 in killing off all fungi. The greatest care must 

 be taken, however, not to set fire to the 

 sulphur, as growing plants are quickly killed 

 by sulphur fumes. A.MC c. 



INSECTIVORA, insek tiv' ora, from two 

 Latin words, insectum, meaning insect, and 

 vorare, meaning to devour, is the name applied 

 to an inferior order of small, timid mammals, 

 which prowl at night and feed chiefly on in- 

 sects. Their teeth are tipped with small pro- 

 jections, by means of which they can easily 

 break the hard outer insect shell. The legs of 

 insectivora are short, and the animals walk 

 with their feet flat on the ground. The order 

 is one of the most ancient of the mammalian 

 groups. See HEDGEHOG; MOLE; SHREW. 



