February, '11] wiNDLE: BULB MITE 127 



THE BULB MITE 



(Rhizoglyphus hijacinthi Boisd., Syn. Rhizoglyphus echinopus Michael) 

 Also known as the "Eucharis Mite" 



By Francis Windle, Westchester, Pa. 



Although thi.s bulb pest seems to be world wide in its distribution, 

 and very serious in the extent of injuries to such plants, but very little 

 attention has been given to it by American economic zoologists, and 

 the importers who were accustomed to seeing and throwing out large 

 numbers of injured and diseased bulbs annually were apparently not 

 aware of its existence, until a system of inspection in Pennsylvania, 

 by the economic zoologist, Prof. H. A. Surface, brought it to their 

 attention the present year. 



It is further quite evident that European growers of bulbs, if 

 acquainted Avith it, have not realized its damaging nature, and have 

 done little, if anything, to check or control it. 



The first inspection was made on August 4th, and the latest on 

 December 1st, 1910, at Philadelphia; both importations being from 

 Japan and containing mites. During the four months intervening, 

 samples of thousands of cases were inspected. Decayed bulbs, upon 

 microscopic examination, showed fungus and bacteria, and some 

 eel-worms (Nematodes). At the same time virtually all decayed 

 bulbs, whether from soft or affected by dry rot, contained mites. 



The question naturally arose what injury the mites were responsi- 

 ble for? Whether they simply followed decay from fungus or other 

 cause, or whether they did direct injury. Investigations were there- 

 fore continued with this point in view. These mites were soon found 

 in solid bulbs, and a wide scope of direct injury was discovered, from 

 slight stains, through grating wounds from eating the scales either 

 base or tops, to complete riddling of the entire bulb. 



The bulk of the importations examined came from France, Holland 

 and Japan, to importers iji Philadelphia and vicinity. They con- 

 sisted of hyacinths, narcissus, lilies and callas of numerous varieties. 

 Some of all these bulbs, from whatever country received, were in- 

 fested with the ''Bulb Mite." They were also found in peony roots. 



The direct injury of these mites was strikingly shown in a late impor- 

 tation of Lilium hrownii from Japan by a Philadelphia seed house. 

 In assorting them a large number had been thrown out, showing no 

 other injury than that caused by the mites, the bases of the scales 

 being so eaten that they would drop off from handling and the 

 "cushion" or root crown alive with them. 



