560 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
A peculiar habit of a large percentage of the adult females of this 
species in descending to the trunk and main limbs of infested trees for the 
purpose of oviposition appears to offer an easy point of attack. Con¬ 
centrating in heavy masses in the crevices of the trunk and under trap 
burlap bands, placed around the trunks of infested trees, at certain 
periods of the year, their removal at that time would seem to offer a 
very satisfactory means of control. This is partly true in the interior 
areas where as previously stated, adverse climatic conditions confine 
this mealybug to a single heavy generation or migration to the trunks in 
the spring, with very light succeeding generations. Under such con¬ 
ditions a trunk treatment might be applied economically. In the coast 
areas, however, the more equable climate permits a continuous de¬ 
velopment of overlapping generations which means a more or less con¬ 
tinuous migration of adult females to the trunks, precluding an effective 
single treatment. Repeated treatments have been demonstrated to be 
of little value and the cost prohibitive. In the case of Valencia oranges 
where the previous year’s crop is often held on the trees several months 
after the new crop has set, the clusters of old fruit serve as suitable 
places in which the adult females cluster for oviposition, further detract¬ 
ing from the value of trunk treatment. While oil emulsions have been 
used safely in these trunk treatments where conditions suggested the 
value of trunk treatment it has been fully demonstrated that water 
applied under pressure is fully as effective and does not materially 
interfere with the work of the many natural enemies which attack this 
pest. 
Biological Control. While there are many native insect predators 
of the Citrophilus Mealybug present in the citrus orchards of Southern 
California, a practical application of this method of control is being 
carried out successfully, using an introduced coccinellid, Cryptolaemus 
montrouzieri Muls. Appreciating the fact that successful commercial 
control using this method is dependent on systematic quantity libera¬ 
tions of an effective enemy at a period in the year which will permit 
several months of continuous uninterrupted activity, laboratory work 
has been developed during the past few years which makes it possible to 
meet these conditions. The Cryptolaemus, introduced into California in 
the early ’90s by Koebele of the United States Department of Agri¬ 
culture has been selected for this work for several reasons. It had al¬ 
ready demonstrated its ability to control the citrus mealybug (. Pseu¬ 
dococcus citri) when introduced into an infested orchard and was de¬ 
termined as being equally effective against the present species; as a 
