Frost Protection - UTL Repository

FROST DAMAGE: PHYSIOLOGY AND CRITICAL TEMPERATURES
FIGURE 4.1
Typical 10 percent and 90 percent bud kill temperatures for cherry trees
corresponding to average dates observed at the Washington State University,
Prosser Research and Extension Centre (Proebsting and Mills, 1978)
CRITICAL TEMPERATURE ( ° C )
0
-5
-10
-15
-20
feb / 28 mar / 12 mar / 24 apr / 5 apr / 17 apr / 29
DATE
10% kill 90% kill
Although freeze sensitivity categories give general information about the cold
that a plant organ can endure before frost damage occurs, hardening and
phenological stage are almost as important. For example, temperature that
produces both 10 percent (T 10 ) and 90 percent (T 90 ) bud kill increases as the
season progresses from first swelling to post bloom (Figure 4.1). In addition, the
temperatures that produce T 90 bud kill in deciduous trees increases more rapidly
and approach the temperatures that produce T 10 kill.
Wang and Wallace (2003) presented a list of fresh fruits and vegetables by
freeze susceptibility categories (Table 4.1.) showing relative sensitivities when
exposed to freezing temperatures. Caplan (1988) gave a list of freeze-tolerance
groupings for annual flowers (Table 4.2). Table 4.4 provides an extensive list of
some of these and other crops.
71