October, ’24] 
armitage: citrophilus mealybug 
559 
observations were made, but recent developments have shown this 
species fully capable of reaching a stage of severity without the attend¬ 
ant protection of the ant. In Orange County less than 25% of the 8,000 
infested acres is attended either by the Argentine Ant or by native 
species. In the Rivera section of Los Angeles County where at present 
the most severe infestations of that species in that area occur, less than 
one percent of the 1,000 infested acres is attended by ants. 
This ability on their part to maintain themselves in the absence of 
ants, is not due to any lack of natural enemies from which the ant 
might protect them as this species is attacked by the same group of 
predators as the other citrus feeding species with one exception, the 
brown lacewings (Sympherobius spp.) and even these seem to be adapt¬ 
ing themselves to this host as each season they are found more often 
feeding in the egg masses. 
I do not intend to minimize in any w T ay the need of controlling ants 
where ever they attend infestations of mealybug but merely to point out 
that at least this species is not entirely dependent on their protection for 
its existence. 
Control 
Mechanical Treatment. This species of mealybug has been re¬ 
ported by Clausen as being the most resistant to cyanide fumigation of 
any of the species attacking citrus, and it is a well known fact that none 
of the others can be successfully controlled in the field by this method. 
In the laboratory, using a gas tight box with a capacity of twenty-five 
cubic feet Clausen was able to secure a one-hundred per cent kill of all 
stages using a 70% schedule for one hour. The eggs succumbed to a 
50% dosage and the adult females to a 60% dosage. The larvae and 
male pupae required 70%. More recent tests by Woglum in the treat¬ 
ment of infested cull oranges intended for byproduct purposes, when 
applied on a large scale, even in a practically air-tight room required 3 
ounces for two hours or four ounces for one hour, to guarantee a 100% 
kill of all stages. It has been fully demonstrated in the field that a 
maximum dosage which may be administered in the field with safety to 
the tree is not sufficient to give a satisfactory commercial kill of any of 
the mealybugs, nor is this species any exception to the rule. 
The citrophilus mealybug has the usual resistance of all other species to 
sprays due to the impervious coating of waxy secretion. Sprays con¬ 
taining an ingredient which will penetrate this wax usually are injurious 
to plant life and are not practical for commercial use. 
