WIREWORMS ATTACKING CEREAL AND FORAGE CROPS. 



31 



These plats were carefully staked and examined from time to time, 

 but at no time could any appreciable difference be noted as to their 

 appearance, Wireworms were as numerous in all the treated plats 

 as in the checks. Wheat was very generally attacked and no dead 

 wireworms were found. 



A number of wireworms were confined in a large tin cage with 

 wheat treated with strychnine as their only food. After two months 

 these larvae were still alive and apparently unaffected by the poison, 

 though they ate the poisoned grain. 



While these experiments were going on at Wilbur a more intensive 

 series was being carried on at Spokane. Here, instead of wheat, 

 sweet corn was used. These experiments were carried on in a field 

 recently cleared of timber. The soil was quite heavy and very 

 moist. Wireworms were very numerous and apparently quite gen- 

 erally distributed. 



On April 5, seed corn was treated in the following manner : 



Lot 1. Coal tar was applied very heavily and Paris green dusted onto it 

 until it was quite green. 



Lot 2 was treated by soaking for a few minutes in copper sulphate and then 

 drying rapidly in the sun. Several potatoes also were soaked, cut into small 

 pieces, in a saturated solution of strychnine. 



This field was all in corn in 1909 and was badly infested with 

 wireworms. In 1910 it was half in wheat on fall plowing and half 

 in potatoes on spring plowing, and was also badly infested this year 

 with wireworms. A plat of each treatment with a check row be- 

 tween each plat was planted on each half of the field. Seventy hills 

 of corn were in each plat. All the' plantings were made on April 

 24. The coal-tar treatment prevented about 90 per cent of the seed 

 so treated from germinating, so this precludes the use, at least as 

 applied to this experiment, of this seed treatment. On May 2 the 

 hills were dug out and the wireworms in each hill counted. Wher- 

 ever wireworms were present they were attacking the seed. The 

 results of this count appear in Table I : 



Table I. — Results of experiment* against wireworms until treated seed. 



Row. 



Treatment. 



Number 



of hills 



examined. 



Number of 



wireworms 



found. 



Number of 

 wireworms 



per hill 

 (average). 



Total aver- 

 age number 



of wire- 

 worms per 

 hill for each 

 treatment. 



1 





10 

 24 

 24 

 24 

 3 

 24 

 24 

 13 

 24 



40 

 138 



4 

 5.75 





11 





4 87 



5 



Coal tar and Paris green 



do 





7 









2 



Check 









4 



do 



35 

 40 

 22 

 93 



1.458 

 1.667 

 1.692 

 3.875 





6 



• do 





8 



do 





10 



.... do 



1. 758 









