COXTROI. OF MKAl.VP.UGS 17 



postdfficc. Tliis is important l)ecausc a few liours confinement in a stuffy 

 mail sack, or overheating- or freezini;-, is likely to kill many of the beetles 

 and undo all the precautions which the shipper has taken to insure the 

 arrival of the beetles in a healthy condition. If it is necessary to keep the 

 beetles for some time before liberation, one of the most satisfactory places 

 is a refrigerator in which the temperature is maintained at 45°-5()° F. 

 Most florist establishments which handle cut flowers have a refrigerator 

 of this kind. 



Method of Liberation. The beetles are lilterated simply by releasing 

 them onto the infested plants from the capsules in which they are shipped. 

 In order to facilitate mating and to reduce the tendency to fly soon after 

 they are released, the beetles under ol)servation were liberated in colonies 

 of about 50 at several places in the infested greenhouse rather than one or 

 two beetles on each plant throughout the beds. So far as possible the 

 beetles were liberated in the morning or evening in order to avoid high 

 temperature and bright light which tends to excite them. It has been 

 reported that beetles flew out of the greenhouse through the ventilators 

 as soon as released, but this never happened in the liberations observed, 

 which were made as stated above. 



Results of Greenhouse Liberations 



During the progress of these experiments, the practical application of 

 Cryptolaemus beetles for the control of mealybugs in the greenhouse was 

 studied from four liberations on gardenias infested with the citrus mealy- 

 bug, and from one liberation on chrysanthemums infested with Mexican 

 mealybug. These observations are summarized in Table KJ. 



Factors Influencing the Success of Liberations 



In general, these demonstrations have shown that Cryptolaemus will 

 control mealybugs in the greenhouse under Massachusetts conditions even 

 to the point of nearly complete eradication, but that there are several 

 factors governing the satisfactory use of these beetles which may interfere 

 with the customary operation of the greenhouse and reduce the practical 

 advantages of their use. These factors are: 



1. The abundance of the mealybugs at the time the beetles 

 are liberated. 



2. The number of beetles liberated. 



3. The time of year when beetles are introduced as it affects 

 their rate of development. 



4. The susceptibilit}' of infested plants and the customary 

 conditions for growing them. 



5. The use of insecticides to control other pests. 



1. Infestation of Mealybugs. A heavy infestation of mealybugs, providing 

 an abundance of food for the Cryptolaemus larvae and favorable locations 

 for oviposition, usually stimulates reproduction. Under such conditions 

 the beetles may lay several times as many eggs as where few mealybugs 

 are present, and the resulting control will be more complete and more 

 quickly accomplished than if the infestation was light and scattered so 

 that the beetles did not lay eggs on as many of the infested plants. If only 

 a few Cryptolaemus larvae are present, they frequently stay on the infested 



