﻿316 POMONA COLLEGE JOURNAL OF ENTOMOLOGY 



clinging power of the cottony secretion which enfolds the eggs is very 

 great. It is this which makes the distribution of the mealy bug so easy. In 

 working with the egg-masses with a needle point, it is very difficult to prevent 

 the eggs and adult mealy bugs, which are spinning the threads during the 

 egg-laying process, from clinging persistently to the point. 



Insects. — Ladybird beetles, including those which prey upon the mealy 

 Lug, are sure distributors of this pest. It is well known that the adult forms 

 are not efficient feeders and are not liable to eat even the young scale and 

 eggs which may be clinging to its legs. The predaceous forms, including 

 Cryptolaemus montrouzieri, Rhizobius ventraUs, Scymnus guttulatus, and 

 Crypto gomus orhicuhts, which pupate among the egg masses of the mealy bug, 

 seldom fly to another tree without taking some of the eggs also. Although 

 this may seem to be dangerous, there is no doubt but that the good done by 

 these ladybird beetles oflf-sets this a thousand fold. I simply mention this 

 as a fact and not as a drawback or as a means of discouraging the use of 

 parasites. 



ll'ind. — Many close observers have noticed that a dirty orchard on the 

 windward side of a clean orchard would infect the first few rows of the 

 clean orchard in one season. This has been demonstrated repeatedly in many 

 localities and is the best argument that the wind is an agent in scale dis- 

 tribution. The young mealy bugs are very small and might easily be carried 

 from their footing by a gust of strong wind and deposited some distance 

 away. Just how much the wind is responsible we have no accurate means of 

 telling, but we do know that if an orchard to the windward in infested with 

 mealy bugs that we are sure to get it soon. It may be that the birds and 

 insects usually fly with the wind wherever possible and that in this secondary 

 manner the greatest amount of distributing is done. 



Irrigating Water. — The white cottony covering thoroughly protects the 

 mealy bugs and their eggs from being destroyed by water, even though 

 completely immersed for several hours. The waxy ingredients in the cover- 

 ing and its ability to retain air globules enables them to float freely. If an}- 

 of the mealy bugs are brushed into the furrow^ before irrigating, and do 

 not get out before the water is turned on, or if any of the adults or the eggs 

 are dropped into the running water, they may in this way be distributed from 

 one section of an orchard to another. Infested culls, dumped into the rivers 

 and ditches may serve to infest regions miles away. The dumping of 

 culls in the dry river beds during the winter, if infested with any scale, 

 should be prohibited and a strict watch should be kept by those in authority 

 for just such acts of carelessness. 



Greenhouse and Nursery Stock. — The greater part of the present dis- 

 tribution of the citrus mealy bug in California may be traced directly to the 

 introduction of infested greenhouse and nursery stock. It is very jjrobable 

 that the first orchard pests came on citrus stock from Florida, while green- 

 house plants are responsible for the infestation at Santa Paula. .\nd no 

 wonder the conditions exist. Nearly every greenhouse in the state is infested, 



