INFECTION WITH MACROSPORIUM TOMATO 8 1 
laboratory or in the field. While a large number of punctures and inocula- 
tions were made throughout the season, the results are so uniform that it 
will suffice to present in tabular form a f^w representative series. 
In Table i are shown the results of picking at random, at the same time, 
fruits of various sizes. These were divided into two equal lots, one of which 
was used for puncturing to determine the resistance of the skin, while the 
other was used for inoculations. 
Examination of this table shows that the resistance of the skin to punc- 
ture increases with the size of the fruit, and likewise that the amount of 
infection varies from ioo% in the case of the smallest fruit to 37>^% in 
the case of fruit approximately 5-6 inches in circumference, with no infec- 
tion above that size. From this series, the point at which the hardness of 
the .skin begins to show any appreciable effect on infection is approximately 
that at which 4.08 grams of pressure is necessary to puncture the skin. 
Table 2 shows the results of puncturing and inoculating fruits of known 
age for seven consecutive weeks. The fruits used in these series were all 
tagged when in blossom. The data show, as in the preceding table, that 
the older the tomato the more resistant is the skin, and that the amount 
of infection decreases when the resistance of the skin to puncture is approxi- 
mately such that 5.08 grams of pressure is necessary to puncture the fruit 
with a 78-micron needle. 
Table 2. Showing the Relation Between Resistance of the Skin to Puncture and Macro- 
sporium Infection on Tomatoes of Different Age 
Age in 
Days 
Color 
Weight in 
Grams, Average 
of ID Fruits 
Equatorial Di- 
ameter in Cen- 
timeters, Aver- 
age of ID Fruits 
Temperature at 
which Stabbing 
was Done 
Pressure in Grams 
Necessary to Punc- 
ture Fruit (Average 
of 100 Stabs) 
Pereentage of Posi- 
tive Infection with 
Macrosporium 
tomato 
7*.... 
Green 
0.24 
0.70 
0.97 
100 
14 
Green 
6.74 
2.30 
21 
2.99 
100 
21. . . . 
Green 
64.66 
5.18 
25 
4.21 
85 
28... . 
Green 
82.37 
540 
22 
4.90 
49 
35-.. • 
Green 
95.10 
5.46 
21 
5.08 
23 1/3 
41... . 
Green 
147.91 
6.55 
21 
5-96 
0 
48.... 
Green 
91.86 
6.92 
23 
6.74 
0 
55... • 
Turning 
25 
5.56 
0 
55--- • 
Red 
162.82 
6:31 
25 
5.10 
0 
* Size of needle used for 7-day-old fruit, 46 microns in diameter. At all other ages 
punctured a 78-micron needle was used. 
Tagging of blossoms to obtain fruits of a known maturity has shown 
that in the majority of cases age of fruit is a better indication of maturity 
than is size. As would naturally be expected, not all the tomatoes in a 
given lot of fruits attain the same size in a given length of time. Such 
fruits, however, have a resistance of the skin in proportion to their age 
rather than to their size, and react accordingly when inoculated. For this 
reason then, it seems, resistance of the skin to puncture is a better index 
of maturity than is the size of the fruit. The former is also preferable in 
