EFFECTS OF FREEZES ON CITRUS IN CALIFORNIA 280 



The early pruned nursery stock was found to be slower in starting 

 growth than unpruned stock, a delay of as much as three weeks being 

 observed in some cases. 



Many growers did not attempt to remove the small frozen twigs in 

 lightly injured trees. Leaving this dead brush in the tree was found 

 to increase the amount of fruit spotting, and decay the next year. 



Removing Frozen Fruit. As soon as it was learned that the fruit 

 had been frozen, some growers had it promptly removed. This cost 

 for oranges from five to ten cents per tree on the average, while some 

 lemon growers had to pay as much as twenty cents per tree. 



Experience demonstrated that there is no need of haste in removing 

 frozen fruit, unless it is to be used for making by-products. Some 

 of the frozen fruit will drop of its own accord and if wood injury 

 necessitates pruning much of the old fruit will be removed by this 

 operation. What remains can be pulled off later at any convenient 

 period. There was no evidence obtained indicating that the succeed- 

 ing crop was injured by this frozen fruit remaining on the tree, other 

 than the injury that may result from the spreading of fungus spores 

 from the old fruit, thereby increasing spotting in the next crop. 



Whitewashing Exposed Trunks. Where trees were defoliated, 

 many growers felt that the bark should be protected in some way 

 from the burning action of the sun. The most feasible way to do 

 this was to whitewash the trees, and this was done in many cases. 

 Where the whitewash was put on before any new growth had started, 

 the appearance of the new growth was delayed about three weeks. 

 When the application was not made until after the growth had started, 

 the tender leaves were sometimes injured. The whitewash was always 

 cooled before using it, but there were many examples where after it 

 had cooled over night, it injured tender growth. Where it was allowed 

 to stand a week before being put on, it had no injurious effects. 



In case there are but a few trees to be treated, the whitewashing 

 of bare trunks and limbs can be done with a brush, but on the larger 

 ranches, the most economical system is to make a thin wash that will 

 go through a spray nozzle and apply it by means of a power spray 

 pump. (See formula below.*) 



The Renewal of Badly-Injured Young Trees. Young lemon and 

 orange trees suffered various degrees of injury, but were much more 

 generally and severely injured than older trees. Severe cases of sun- 



* Formula for California Whitewash: Take 30 pounds of quick lime, 4 pounds 

 of tallow, 5 pounds of salt, and mix together, slake slowly and blend. Dilute with 

 enough water to make mixture flow well. 



