April, '15] 



PARKER: ALFALFA LOOPER 



289 



than for several previous years. A heavy infestation of the alfalfa 

 looper was the only apparent cause for this sudden falling off in weight. 

 The yield was noticeably hght wherever the infestation was at all 

 severe. The quality of the hay obtained was also greatly lowered, 

 for the loss in weight was borne by the leaves rather than by the less 

 valuable stems. 



Sweet clover was more severely attacked than alfalfa, but as very 

 little is grown for hay, no estimate of the loss in tonnage could be ob- 

 tained. Many patches growing wild were stripped entirely bare of 

 foliage and in some of them the larvae were astonishingly abundant. 

 One patch" was seen that was literally covered with loopers. On one 

 plant forty-five worms were counted on one small branch and the 

 remaining branches were just as heavily infested, while the ground 

 beneath was covered with a squirming mass of larvae. 



When infested alfalfa was cut, thousands of loopers were left with 

 but a scanty supply of fresh green food and they at once began a mi- 

 gration to other crops. Such a migration was seen at Huntley. An 

 infested crop of alfalfa was cut on June 9 and on the following morning 

 a heavy migration of worms was taking place from the cut alfalfa to 

 an adjacent field of sugar-beets. In less than twenty-four hours from 

 the time the alfalfa was cut, twelve rows of beets at the edge of the 

 field had been eaten clear to the ground and others were much damaged. 

 The owner was attempting to save his beets by spraying with Paris 

 green, but so fast were the worms coming in that the damage was 

 done before the poison could take effect. He was advised to turn 

 water into an irrigating ditch that separated the two fields and by 

 this means the migration was stopped. 



Many beet fields were invaded in like manner and their scalloped 

 and irregular margins were very noticeable as one drove along the 

 highways. However, beets that had been defoliated soon sent out new 

 tops and by harvest time could not be distinguished from those that 

 had escaped attack. 



Gardens and some of the field crops were attacked in proportion to 

 their nearness to infested alfalfa and sweet clover. A half -acre garden 

 which had been planted to squash, melons, cucumbers, beans, peas, 

 corn, and beets was seen about ten days after it had been invaded by 

 loopers from a neighboring alfalfa field. Not a vestige of the squash, 

 melons, or cucumbers remained; beans and peas existed only as bare 

 stems; corn was badly eaten and beets were sending out new tops after 

 having been eaten to the ground. 



Many patches of melons that were attacked made a new growth 

 and set much fruit, but a set-back of several weeks in a growing season 

 which at the best is short, was sufficient to prevent the melons from 

 ripening before the coming of fall frosts. 



