8 



CIRCULAR 516. U. S. DEPT. OF AGRICULTURE 



spread out in a shallow layer in this tray without packing the foliage, 

 and this will prevent the uneven penetration of the heat during treat- 

 ment. As shown in figure 5 c, a temperature of 110° F. was reached 



Figure 6. — Normal gerbera leaf (A) compared with one from plant injured by 

 treatment in hot water (B). The treated leaf shows necrotic brown areas on 

 each side of the midvein. 



between 2 and 3 minutes after beginning treatment, among both crowns 

 and leaves; and the temperature decreased more rapidly after treat- 

 ment than it did in the treatments in crates (fig. 5, a and b). 



