20 



FUMIGATION INVESTIGATIONS IN CALIFOENIA. 



belong to the latter class. The following statement and comparative 

 table have l^een prepared which indicate the wide range of variation 

 in these schedules: 



Dosage schedules. — For the information of those who may be inclined to doubt 

 the writer's contentions in this bulletin with relation to the generally chaotic con- 

 dition of fumigation schedules published in the interests of California citrus growers, 

 a table has been prepared which includes nearly all of the more important sched- 

 ules, together with a comparative analysis of the same. The dosages for trees of 

 given dimensions were duly computed. Having this data at hand and utilizing 

 the dosage allotted to each individual tree, it was possible to work out the rate of 



Fig. 10.— a typical California lemon orchard with row of fumigation generators placed ready for use 

 the following night. (Original.) 



dosage per 100 cubic feet of inclosed space at which that particular tree was being 

 fumigated. This has been done for all trees in the schedules proposed by several 

 writers, and the results have been arranged in the latter half of the table. 



A glance at this table will show that the schedules of Morse, Coquillett, and Wood- 

 worth were all based on the cubic contents of the trees, which were dosed at a uni- 

 form rate, but without regard to the leakage of gas. Large trees are dosed at the 

 same rate as small ones, thus giving a lack of uniformity in results. All of the other 

 schedules detailed in this table were apparently prepared with little or no regard 

 to the cubic contents represented by trees of different dimensions. Although it 

 would appear from the table that leakage was taken into account, inasmuch as the 

 smaller trees receive a greater rate than the larger ones, proper allowance could not 

 be made for this factor without definite consideration of the cubic contents. Con- 

 sequently the decrease of rate recommended is in all cases irregular and widely 

 removed from a rate proportionate to the actual leakage. The fact that trees in- 



