April, '22] GREENHOUSE INSPECTION, DISCUSSION 157 



tion, to issue to our greenhouses a certificate reading like this: that 

 they are practically free from the usual greenhouse pests and are apparent- 

 ly free from danger. 



Of course, if a greenhouse has scale all over its palms, we refuse to 

 issue them a certificate at all for palms. Or, we require them to agree 

 not to ship any palms under a certificate we give them, and the cer- 

 tificate will apply only to stock in their greenhouses which seems to be 

 free from scale or insect pest. We issue certificates to only those green- 

 house owners who seem to take all the reasonable precautions to keep 

 down the common insect greenhouse pests. It would be an awful job 

 in Illinois to inspect every shipment that is sent out from greenhouses; 

 in fact, it would be impossible. 



Mr. T. J. Headlee: I have felt for a number of years that the 

 handling of the greenhouse stock situation should be given attention, 

 and if Mr. Sasscer believes that the information that we now have on 

 the different species of insects as to dangerous character, has gone far 

 enough, I would like to make a motion that a committee be appointed, 

 to throw this whole matter into some sort of definite shape for considera- 

 tion at the next meeting. But I would like to have Mr. Sasscer answer 

 the question first, as to whether he feels that the information along 

 this line has gone far enough to permit reasonably fundamental ac- 

 tion. 



Mr. Sasscer: Doctor Headlee has asked a question that I don't 

 believe I am competent to answer. If anyone had told me several years 

 ago that the strawberry root worm would have become a rose pest 

 in greenhouses, I would have been inclined to doubt him. Take the 

 chrysanthemum midge for example. We fought desperately to keep it 

 out of the Washington greenhouses, but it finally became established. 



The great difficulty, it seems to me, is to determine what is an injur- 

 ious insect in a greenhouse. Some five or six years ago the Bureau of 

 Entomology initiated a project for the purpose of studying insects 

 infesting ornamental plants in greenhouses, and a large mass of data 

 has been assembled. Previous to undertaking this problem, Mr. J. J. 

 Davis had been working up a bibliography of greenhouse insects, and 

 he was generous enough to turn it over to us. However, there are a 

 great many insect pests in greenhouses at the present time of which we 

 know little. I am afraid that I am not in position to say that we know 

 enough about greenhouse insects to lay down a definite rule that will hold 

 for five or ten years. 



Mr. Headlee: I believe I will make the motion anyway, because 

 we are in very much the same boat in all lines of insect work. I don't 



