63 



of the average number of leaves grazed by D. dormam" per snail hour (L) 



is as follows: 



L = 13 1 .34 cm ^/sna il hour 

 28.8024 cm'^/leaf 



[ = 4.56 leaves/snail hour 



Calculations of the quadratic equation describing the relationship 

 of percent sooty mold present by time are given in Table 4. 



The original percentage data were transformed by use of Arc-sin 

 tables to allow for computations with percentages (Table 5). An ex- 

 amination of the significance of the various sources of error showed 

 only the intercept and the day by snail (N-X) interactions as being sig- 

 nificant (Table 4). Statistically, factors such as time (N) or time^ 

 (N ) had little if any effect in accounting for the reduction in the 

 sooty mold on the leaves. As was expected, the number of snails (X) 

 by time (N) interaction was significant. That is to say, by increasing 

 the snail population, over the six days you would get a reduction in 

 sooty mold. There was a reduction as opposed to an increase because the 

 value was negative for N-X interaction. It was possible to make a di- 

 rect comparison of the different cubic foot units, without having to 

 deal with the variation in leaf numbers (NLVS) because the NLVS inter- 

 action was not statistically significant. The calculated values for 

 Figure 23 are displayed in Table 6. 



Sooty mold was calculated to be consumed at a rate of 131.34 

 cm /snail hour. The basis for the linear representation was derived 

 from a quadratic equation where only the intercept and N-X interactions 

 were significant. 



Snail density and its effect on citrus rust mites . The data fol- 

 lowed a Poisson distribution which is found generally when dealing with 



