- 10 - “ 
Cyclamen mite succumts to hot water.--Laboratory experiments 
indicate that immersion of Cyclamen plants in hot water at 110° F. for 
10 or 15 minutes will kill Tarsonemus pallidus Bks. within the curled 
leaves, flower buds, or between the bases of leaves at the crown of the 
plant without injury to the plant, according to F. F. Smith, of the 
tropical greenhouse, Washington, D. C. Dr. Smith's work indicates that 
"the mites gain entrance to the folded young Cyclamen leaves while still 
mere buds only one-eighth to one-fourth inch long and to the flower 
buds at a slightly later stage. The mite breeds up to large numbers 
in these inaccessible places where distortion of growth adds to their 
protection. It therefore seems that a control program, to be effective, 
must be started early in the season * * *. Some form of heat treatment — 
seems to be one logical point of attack in attempting to save a Cyclamen 
crop which is already infested." 
Cyanide fumigation effective against the broad mite but not against 
the Cyclamen mite.--Dr. Smith also reports that, although the Cyclamen 
mite is little affected by cyanide fumigation at dosages tolerated by 
the host, the broad mite (T. latus Bks.) may be killed by this treat— 
-ment. A dosage of three-eighths to one-half ounce per 1,000 cubic feet, 
especially at 65° F., has given consistently high kills of the broad 
mite in all stages except the pupal stage, which seemed to be resistant 
to fumigation at all the temperatures used. The tests "indicated that 
thrips (Heliothrips haemorrhoidalis Bouché) and mites are killed at about 
the same dosages, which are slightly higher than those (one-eighth to one— 
fourth ounce) required to kill the aphid Myzus persicae Sulz. In lab-— 
oratory tests, using pepper and Impatiens sultani as hosts, infested 
plants were freed of the mites by three fumigations at 4—day intervals." 
Vapor-heat treatment for insects in narcissus and lily bulbs.—-In 
connection with vapor—-heat treatments of narcissus and lily bulbs at 
Sumner, Wash., experiments to determine the minimum time required to 
give complete mortality of the insects concerned have been Carried out 
teem et 



en re ne cre ere eee 
Ny _Time required for complete mortality (hours) 
Temperature (° F.) Merodon equestris Eumerus spp. Liothrips vaneeckei 
ia a i os Siemon pe ee A DNL ADIT ain ra LI Be ES 


106 6 5 1 3/4 
107 An /2 31/2 48 
108 Sel /zZ 2 11/2 
109 AMY f a 
110 1.3/4 3/4 1 
111 11/4 1/2 Pies 

Exposure to 105° F. did not give a complete kill of Merodon equestris 
after 9 1/2 hours or of Eumerus spp. after 7 1/2 hours. 

