Figure 1 — Gouty pitch midge damage on ponderosa pine. Tree on left was not damaged. Tree on right was 

 heavily damaged. 



Table 1 — Model for analysis of variance and expected mean 

 squares 



Source of 

 variation 



df 



Expected 

 mean squares 



Block 4 + fxf^^ + ipSTg 



Stand 47 d"^ + pcf^^ + pbcs%^ + pdf Vg 



Family in stand 1 82 o'^ + fxf^^ + pto^/s 



Experimental error 916 (f^ + pd' 

 Within plot 2,608 (f^ 



EE 



where: fe = 5, S= 48, /= 229, f = 4.6 harmonic mean of 

 families in stands; p = 3.00 harmonic mean of individuals 

 within plots 



RESULTS 



The regression of total tips per tree (TT) for the sample 

 resulted in regression coefficients df a = -68.0 and b = 

 74.1 tips per meter, = 0.69. 



The average level of damage by gouty pitch midge was 5 

 percent. Individuals varied from to 57 percent, and 

 families varied from (15 families) to 20 percent. The 

 frequency of damage classes by individual is summarized 

 in table 2. 



Differences among families within stands were highly 

 significant (table 3). Variance components are listed in 

 table 3. Heritability based on individuals was 0.48; for 

 families 0.60. 



There was very little relationship between the amount 

 of damage caused by the gouty pitch midge and the 

 heights of the trees in 1985. for families was 0.02. 



2 



