CORKY-PIT IN APPLES

Evening Post, Volume CXIX, Issue 110, 11 May 1935, Page 14

CORKY-PIT IN APPLES

BIPORTANT DISCOVERS CHECKING THE DISEASE I

w Since 1912 a disease of unknoitfni origin- has been present in the Nelson district. The condition' is character' ised by the presence- of numerous brown, corky areas in the flesh of tjie fruit, especially in the region of tfce core. To this disease has been applied provisionally the name corky-pit,, as jit most aptly describes the symptoms, jit v is also known r locally as poverty-pit, cork, corky-core, brown-heart, crinkle, drought-spot, or bitter-pit. Reports fit investigators in America and Australia indicate that there are similar diseases iu^ those countries, but, at present |it ■ is^not yet possible to associate these with the-New Zealand condition- \ Although corky-pit has been known in. the Nelson district for twenty-thrjw years; it assumed economic importance only in certain seasons, notably those of 1923-24, 1925-26, and again during the past four years. ~.'■■. [ 'During the winter of 1933 a p*e» liminary field survey, of •the 'CorKy* pit position was made'tnrough the Nel« son district. From information th!u» secured it appeared, possible that the disease might be due to mineral de» ■ficiency. In the spring* of 1934 wejr« commenced numerous field investigations, which ■■ included ,a series of Injection experiments, the purpose fit which was to determine'whether the disease was influenced- by supplying the tree with small, amounts of various mineral salts. Salts of the follow* ing were tested: Aluminium, barium, boron, calcium, copper, iodine, ircin, magnesium, manganese, molybdenum, nitrogen, sodium, .totanium, uranium, vanadium;, and zinc. The officer in charge of these experiments, Mr. J, D. Atkinson, tabulates the results he,obtained iathe last "number of f the "New Zealand Journal • of ScienceI,and Technology."- Sum.marised, these results show that fruit from trees treated with boracic acid remained'free from -corky-pit,, or eke • with only a very low percentage 'pt infection. Fruit from trees subjected j-to -other treatments were severely | affected by the disease. As the .'experiments suggest that corky-pit is n>aI terially influenced by the addition ~'ot boron, further investigation wiUyba , made. 'If corky-pit 'can be abolished from the list of diseases from-which \he Dominion's apples are liable :to 'suffer, a very great advantage will accrue to the fruit'trade,'especially-in its export aspect. j , •