PRESENT SYSTEM OF SCHEDULING DOSAGE. 23 
THE PRESENT SYSTEM OF SCHEDULING DOSAGE. 
When we understand thai up to the present time only one approx- 
imately accurate 4 dosage schedule has been proposed by the fumiga- 
tion experts of California, and, what is more confusing, thai no two 
tables agree in all respects, we can do1 wonder thai the practical 
fumigator has turned from them in perplexity. Finding the tables 
o( Little assistance, the fumigator has had to determine his own 
dosage from practical experience and the results secured. It' be 
failed to destroy the scale on a 6-foo1 tree in using l ounce of cyanid, 
he increased his dosage for the next 6-fool tree, and so on. lie has 
also Learned that the dosage required to destroy some scales is 
greater than that for other species, ruder the system at present 
in vogue the dosage is usually estimated in the daytime. The 
estimator, who ordinarily is the man in charge <>!' the outfit, starts 
out in an orchard equipped with cross-section paper or a schedule 
sheet. lie walks between two rows of trees, jotting down in the 
corresponding squares of the schedule sheet the dosage which he 
believes the trees should receive. If he is a careful scheduler he 
will look at the trees from different side^ before indicating the 
dosage, as trees are sometimes more compact on one side than 
on another. Less careful men set down the dosage for the two 
rows of trees while moving along as fast as they can walk. The 
writer has seen some schedulers walk through the field at a rapid 
pace, taking four rows at a time. 
The estimation of dosage in this manner is mainly guesswork. 
Measurements of the trees are made by the eye: consequently, suc- 
cessful results depend very largely upon the accuracy of the estimator's 
eye-measurement, supported by his experience in fumigation. The 
most careful of estimators are very irregular in their scheduling. 
This point has already been mentioned by Professor Woodworth. 
From measurements taken after many fumigators, we have found 
none who did not at times vary more than 50 per cent in dosage esti- 
mates for t pees containing exactly the same cubic contents after being 
covered with a tent. Frequently the variation is as high as 100 per 
cent. The results secured by a few of the more careful and expert 
schedulers have been good as a whole. These men, however, can 
cover but a small portion of the citrus groves of southern California 
in one season. 
The writer has been shown orchards in which it was stated that all 
the scale had been destroyed by the use of heavy dosages. Even if 
this were the case it would show that the smallest percentage or 
strength of dosage used on any tree in those orchards was sufficiently 
large to desl roy the scale. Since, as we have found, expert fumigators 
a Bui. L52, I'niv. of Cal. A.gr. Exp. Sta., L903. 
