APPEARAX( 1 ES MISTAKES FOR BITTER PIT. 



23 



was made across the discoloured patches, there was a browning of the flesh beneath corresponding 

 to the surface discolouration, and extending inwardly in a crescent form to about one-eighth of 

 an inch. 



After testing the effects of various chemical substances applied to the skin of the apple, 

 I cannot emphasize it too strongly that all this production of external spots and smears has really 

 nothing to do with Bitter Pit. This disease originates from within, and the action of an external 

 agent on the skin is something totally different. 



LOCAL POISONING. 



The action of various poisons on the sensitive cells of the apple is now receiving the attention 

 of various investigators, and it is an interesting bio-chemical problem to determine the nature and 

 extent of the injury. Since arsenical poisons are now so extensively used in checking the Codlin 

 moth, their effect upon the fruit has naturally been brought under notice, and, so far as these 

 investigations dealt with the action of poisons on plant tissues, the results have been of great 

 scientific value. But when spraying with such compounds was propounded as the cause of 

 Bitter Pit in apples, then a new turn was given to the question, and evidence had to be adduced 

 for or against the theory. Dr. Jean White (95) brought forward this theory in 1911, in a paper 

 read before the Royal Society of Victoria, entitled " Bitter Pit in Apples," and it may be briefly 

 stated, in her own words—" The results of my observations, and of the experiments performed, 

 without one single exception so far, seem to indicate that the complaint popularly known as Bitter 

 Pit is, strictly speaking, not a disease at all, but rather a symptom of slow local poisoning, and that 

 in the cases actually examined so far, it appears to be due to the poisonous compounds sprayed on 

 to the surface of the fruits for the eradication of pests, more especially insect pests." Bitter Pit 

 was generally considered to be due to internal causes, and not to external agencies, but, apart from 

 that, there were at least three fatal objections to the theory from the practical stand-point. First, 

 I had plucked apples affected with Bitter Pit from trees which had never been sprayed with 

 arsenical compounds. Second, I had received badly pitted apples from Western Australia, where 

 the Codlin moth was practically unknown, and where, consequently, no spraying had been done. 

 Third, there was reliable proof in official publications in South Australia that Bitter Pit existed 

 there before spraying was thought of. Under these circumstances, I did not deem it necessary 

 to pursue the subject further, but, by special request, I have carried out definite experiments to 

 see if Bitter Pit was produced in the absence of spraying, and some of them are on the lines laid 

 down by Dr. White herself in the paper referred to. " As I am anxious to have this theory proved 

 or disproved as soon as possible, I should like to suggest that fruit-growers in the different States 

 should test it in their own orchards. A good plan would be to leave one central tree unsprayed, 

 and also those forming a kind of circle round it. In this manner the danger of spray material 

 being deposited upon the surface of the fruit on the central tree would be minimized in an orchard 

 which was otherwise sprayed." 



EXPERIMENTAL EVIDENCE. 



In an orchard at Deepdene, where the Cleopatra apple-trees were being cut down and 

 re-grafted on account of Bitter Pit, I had twelve trees of this variety reserved, in order, to test the 

 effect of non-spraying. They were in a corner of the orchard, and care was taken, when the other 

 trees were being sprayed, that none of the spray was carried in that direction. At the end of the 

 season the result was that the twelve trees produced 23£ lbs. of fruit, every apple being badly 

 affected with Black Spot so as to be unmarketable, and twelve apples with Bitter Pit. 

 (Fig. 122.) 



