74 



per acre. At planting, double furrows were opened up ten feet apart, and a good big 

 forkful of manure was dropped every eight feet in the furrows. Over this manure, the 

 seeds were planted. From the time the plants appeared until the runners closed the 

 spaces between the rows, the ground was kept mellow by frequent cultivation. Before 

 the plants started to run they were thinned to two plants in each hill. High fertili- 

 zation and mellowness of soil promoted vigorous growth and the formation of secondary 

 roots from the nodes of the runners. This formation of secondary roots was favored 

 also by the unusually even distribution of rainfall throughout the summer. The im- 

 portance of these secondary roots can be judged by the fact that every plant in the 

 field was infested with borers, and the great majority suffered a complete rotting off 

 of the main stem as a result. In spite of this, the harvest of squashes was declared to 

 be satisfactory. 



Covering the Rumiers. — Some growers make it a practise to insure the "striking" 

 of secondary roots by covering the runners with earth at about a foot from the 

 ba.se of the plant. Fertilizer is sometimes added at these points. This practise is 

 a useful one, and often serves to reduce materially the amount of damage done 

 by the borers. 



Cutting out the Borers. ■ — The practises mentioned above, while they often aid 

 in mitigating the severity of the scjuash vine borer attack, have no direct effect 

 upon the borer itself. The best method heretofore practised for actually killing 

 the borers has been the custom of cutting them from the vines. Slitting the stem 

 lengthwise in both directions from the frass-clogged hole and bending back the 

 cut portion will usually reveal the borer, which can then be removed and killed. 

 If the stem is subsequently covered with earth, the operation will have little injurious 

 effect upon the plant. By constant watchfulness from the middle of July to the 

 first of September, a few plants in a home garden can be protected from excessive 

 borer injurj^ by this means. 



The Use of Insecticides. 



Certain insecticides have been tried in the past against the squash vine borer, 

 and have been declared valueless. Among these were arsenate of lead painted 

 thickly on the squash stems, and wrappings of tarred paper. Injections of various 

 toxic substances have been tried at this station, but without success, both because 

 of the nature of the burrows and of the webbing of silk and frass which obstructs 

 them. Studies of the life historj^ and habits of the species in 1920 led to spraying 

 experiments in 1921 ^\^th the following materials:- — 



Material. Possible Action. 



Arsenate of lead powder, 3 pounds m 50 Poisoning of newly-hatched larvae, 

 gals, water. 



Nicotine sulfate (Black-leaf "40"), 1 part Penetration and killing of the eggs — re- 

 in 100 parts of water. pelling of adult moths. 



Bordeaux mixture, 4-4-50 formula. Repelhng of adults. 



Preliminary' experiments with these materials were conducted in 1921 and 1922 

 leading up to the successful field applications of 1923. On the basis of this work, 

 the following spraj^s were applied in 1923: — 



Material. Action of Spray. 



Black-leaf "40", 1-100, 1-250, and 1-500. Toxic to eggs. 



Arsenate of lead powder, 2 pounds in 50 Poisons newly-hatched larvae as they 



gals, water; 3 pounds in 50 gals, water, chew at surface of squash plant. 



plus "Kayso" sticker. 



The work was done on a commercial scale at Littleton, in cooperation with a 

 squash grower, and at the Agricultural Experiment Station at Amherst. It is here 

 reported in some detail. ■ 



