SOME PHASES OF ONION CULTURE. 461 



previous year. Sometimes the crop may be planted a little late, 

 after the fly has emerged and laid its eggs, or a trap may be used. 

 In some cases a generous application of fertilizer may add vigor 

 to the plants. Repellants, such as sand and kerosene, one cup 

 of kerosene to one bucket of sand; carbolized lime, white helle- 

 bore, powdered tobacco, etc., are often used, simply by scattering 

 in the rows. 



A poison bait spray for controlling the onion maggot has 

 been used with considerable success in some localities. It should 

 be applied from the time the onions are up until about May 20th. 

 This spray can be made by mixing one-fifth ounce of sodium 

 arsenite, one-half pint molasses and one gallon of water. 



Even more important than the maggot is the onion thrip, 

 also known as onion louse, and causing damage known as 

 white blast, "silver top," or "white blight." The female by 

 means of a tiny saw-like organ, cuts a slit in the leave or stem 

 and deposits her eggs there. In a few days the young thrip 

 has hatched and begins feeding. Growth is rapid. In one or two 

 weeks they cease feeding and transform to the nymphal and then 

 to the adult stage. Under favorable conditions in three weeks the 

 entire life cycle will be completed. The injury is soon seen in a 

 whitened appearance of the leaves, due to rasping and sucking 

 the juices. Natural enemies of the thrips are the lady bird 

 beetles and a parasite. Heavy and driving rain storms destroy 

 great numbers of this insect. Clean methods of field culture 

 cannot be too stringly advised, as the thrips feed on many weeds 

 and on nearly all vegetables. A spray of nicotine sulphate may 

 be used if the thrips have gained headway. 



Cutworms, onion smut and blight are also often troublesome 

 but can be controlled by the proper methods. 



Irrigation in many sections is not generally used, although 

 the overhead pipe systems are being used more every year. Such 

 a system costs about $125 per acre, exclusive of a pumping plant. 

 The cost of operation is small. An average of $15 per acre, 

 which includes cost of water used, is a fair allowance. Results 

 from one-fourth to twice the yield have been reported by the use 

 of the overhead system. 



There are many small details that are of considerable im- 

 portance in securing an increase in crop yield, and the grower 

 should consider all methods of improvement in planning his 

 investment of capital. Good seed, good drainage, proper use 



