An Investigation of the 

 Dipping and Fumigation of Nursery Stock 



K. C. SULLIVAN 



More than one hundred years ago the first nursery was started in Mis- 

 souri. At that time Missouri was a part of the Great West and was settled 

 mostly along the water courses. The fruit industry at that time was undevel- 

 oped. Today there are in Missouri more than one hundred nurseries. One 

 of the largest, if not the largest, nurseries in the world is located in Mis- 

 souri and the acres of some of the others run well up into the hundreds. 

 The growth of the fruit and nursery industry in Missouri has been remark- 

 able. Also, the increase in the number of injurious insect pests of the fruits 

 has been equally as remarkable; in fact, they have increased so rapidly that 

 in some sections farmers are abandoning the fruit industry and entering 

 some other line of work in which insect pests are not so troublesome. 



Some of the most injurious insect pests and fungous diseases of fruit 

 trees, that we have to contend with, were first introduced and scattered over 

 the country on nursery stock. The most noted and most injurious one of 

 these is the San Jose scale. This scale is so destructive that every state in 

 the Union and the Federal Government have passed stringent laws regard- 

 ing its distribution and control. Missouri has a law which forbids anyone 

 in the State to distribute or dispose of nursery stock of any sort upon which 

 there is San Jose scale ; nor is anyone from outside the state allowed to 

 ship infested plants into the state. In many states there is a law which 

 requires that all plants badly infested with San Jose scale be destroyed and 

 that those which are not visibly infested be treated with the best known 

 remedies for the destruction of the scale. 



The San Jose scale has become so widely distributed in Missouri that 

 strong measures have been taken to stop further distribution. It is usually 

 carried from one section of the country to another upon nursery stock. 

 Practically all original infestations in Missouri were started from' scale 

 brought into the community upon nursery stock. Since the San Jose scale 

 is usually carried into a non-infested district upon nursery stock, the logical 

 thing to do is to produce clean stock; that 1 is, nursery stock upon which 

 there is no scale. This is very difficult to do, especially where the scale has 

 once obtained a foothold. 



From time to time, various remedies have been recommended by 

 which nursery stock can be treated and the scale destroyed. Some of these 

 treaments killed the trees as well as the scale; others did not always kill 

 the scale, and others cost so much that they were not practical, especially 

 with the smaller nurserymen. 



During the past five years the writer has been constantly in touch 



