t 
of the disease. This educational feature helps agents associate 
symptoms not present in his sample with the disease. 
The foregoing is one example of a system which is much more 
expansive in its capabilities. Currently, 10 programs involving 
agricultural economics, plant pathology, and* soil and crop 
sciences are operational. In addition to disease identification, 
the programs include cost analysis, income tax analysis, soil 
nutrition and herbicide recommendations, sprayer calibration, 
timing of eradicants for apple scab control, and retrieval of 
pesticide tolerance and compatibility data. 
The system has a potential for a wide number of uses and 
is relatively inexpensive. Normally, a touch-tone telephone 
would replace one of the rotary dial type. Rental is $5.00 to 
$8.00 a month more than the dial telephone. The cost for computer 
time has been under $2.00 for most of the programs. Long distance 
toll charges have averaged less than $1.00 per call, free where 
wide area telephone service (WATS) is available. 
Initial support to develop this system was provided by the 
Kellogg Foundation. Eventually, it is anticipated the user will 
be billed directly. Experience gained from the Michigan TELFARM 
and DHIA programs indicate farm businesses will readily pay a 
fee when a needed service is providedA. L. Jones and S. B. 
Harsh [Reprinted from Phytopathology News, vol. 4, no. 10, Oct*, 
1970] . 
RECENT LITERATURE 
Adams, R. P. Contour mapping and differential systematics 
of geographic variation. Systematic Zoology, 19: 385-390. 
Crovello, T. J. The effect of change of number of OTU'S in a 
numerical taxonomic study. Brit'tonia, 20 , 1968 , pp. 346-67. 
Crovello, T. J. Effects of change of characters and of number 
of characters in numerical taxonomy. American Midland 
Naturalist, 81, 1969, pp. 68-86. 
Crovello, T. J. Numerical taxonomy: its value to mosquito 
systematics. Mosquito Systematics Newsletter, 1, 1969, 
pp. 63-7. 
Hale, M. E. & R. Creighton. An automated system for recording 
exchanges. Flora North America Report no. 32, 1970, 1-9. 
Maelzer, D. A. The regression of log N [to base n+1] on log N 
[to base n] as a test of density dependence: an exercise 
with computer-constructed density-independent populations. 
Ecology, 51, pp. 810-822. 
Menkhaus, E. J. Time sharing—more glitter than gold. 
Business Automation, Nov., 1970: 36-42. A peep into 
the future of time-share computing. 
