CALIFORNIA OLTVE CULTURE PESTS. 



83 



of our native insects, like the lace-wing fly (Chrysopa calif or- 

 nica), syrphus fly (Catabomba pyrastri), and a minute internal 

 parasite (Dilophogaster calif ornica). 



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Male, enlarged. Larva, enlarged. Female, enlarged. 



BLACK LADYBIRD (Rhizobius ventralis). 



The combined efforts of all of these friendly insects did not 

 materially decrease the scale until a black ladybird (Rhizobius 



ventralis) was introduced 

 by the State Board of 

 Horticulture from Aus- 

 tralia. Singularly, 

 though this ladybird has 

 increased enormously 

 wherever it finds humid 

 atmospheric conditions, 

 in interior localities, 

 where the atmosphere is 

 dry, it has not developed 

 with such rapidity. 

 The ladybirds are col- 



Collecting Rhizobius beetles for distribution . J 



among orchards infested with black scale. lected and placed On the 



trees just before sunset. The beetles fly from tree to tree, and 

 in this way scatter throughout an orchard. Many thoughtful 

 growers aid the ladybird in colonizing by carefully collecting 

 the beetles from certain trees and liberating them on other 

 portions of the orchard. Before winter sets in inverted corn 

 husks are tied among the branches of the trees for the purpose 

 of giving shelter to the ladybirds, so that they may not perish 

 during the cold winter months. 



