10 INSECTS AFFECTING VEGETABLES. 



The results of the experiments may be summarized as follows: 

 Experiments with insecticides. 



Experi- 

 ment 

 No. 



Date. 



Insecticide used. 



Effect on larvae. 



Injury to 

 foliage. 



Remarks. 



1 



2 



3 



1910 

 Sept, 1 



Sept. 7 

 ...do 



Nov. 1 

 Dec. 16 



Paris green, 4 pounds, and 

 lime, 4 pounds, in 100 gal- 

 lons of water. 



Paris green, 2 pounds, and 

 whale-oil soap, 8 pounds, 

 in 100 gallons of water. 



Arsenate of lead, 1£ ounces, 

 and molasses, 1 quart, in 

 1 J gallons of water. 



Lime-sulphur solution, 1 

 gallon, in 15 gallons of wa- 

 ter. 



Lead chromate, 2 ounces, in 

 8 gallons of water. 



Ineffective 



Absolutely ef- 

 fective. 



Ineffective 



Slight. . . 



None 



...do 



The poor results were due to 

 the poison being applied to 

 the upper surface of beet 

 leaves where the larvae 

 failed to reach it. 



Spray applied properly to the 

 under surface of beet leaves. 



Applied to the upper and 

 lower surface of Amaran- 

 thus leaves. There is no 

 apparent reason for its fail- 

 ure to kill the larvae. 



Applied to beet leaves. A 



4 



do 



Severe . . 

 None 



5 



Possibly effec- 

 tive. 



few larvae were killed by 

 contact with the solution. 

 Applied to beet leaves. The 

 poison was very slow in its 

 killing effect. 



It will be seen from the record of experiment No. 2 that this web- 

 worm can be effectively controlled on beets with Paris green. When 

 this poison is applied at the rate of 2 pounds in 100 gallons of water 

 it will not burn beet foliage and in this formula it is better to omit 

 lime and use whale-oil soap. The soap serves as an effective adhesive 

 agent and when it is used the poison is very evenly distributed over 

 the leaf surface. 



As " spinach " is used as food by human beings while the plants 

 are still young and tender, it is obvious that it would be unsafe to 

 spray this crop with an arsenical. Instead of an arsenical it is 

 recommended that the following nicotine-soap combination be used 

 on spinach: 



Nicotine sulphate 1 fluid ounce. 



Whale-oil soap 4 ounces. 



Water 4 gallons. 



This formula was successfully used by the author at Honolulu, 

 against the common cabbage worm (Pontia rapce Linn.), the larva 

 of the diamond-back moth (Plutella maculipennis Curtis), a looper 

 (Autographa precationis Guen.), and the beet army worm {C aradrina 

 exigua Hbn.). It has also been used effectively against several 

 species of aphides or plant-lice and thrips. Although this formula 

 has not been actually tested on Hymenia larvae, there is no reason to 

 believe that it would not prove entirely effective. 



For treating moderate-sized plats in gardens a portable com- 

 pressed-air sprayer or a bucket pump will give good results. The 

 sprayer should be fitted with a short extension rod, an elbow, and 

 a nozzle of the Vermorel type, which will deliver a fine, mist-like 



