17- 



All that is needed to perforin the starch tests are (1) a 

 chart with instructions; (2) some iodine and potassium iodide 

 crystals; (3) a shallow dish; and (4) a pocketknife. A chart is 

 available, entitled "Evaluating apple maturity. Using the 

 starch-iodine test." It can be obtained free from Dr. E.G. 

 Lougheed, Horticultural Science Department, University of Guelph, 

 Guelph, Ontario, Canada NIG 2W1. The chart also contains 

 instructions for testing apples. 



The chemicals can be obtained from a pharmacist, who may 

 have to order them for you. Although they are expensive, small 

 quantities go a long way. The chart described above includes a 

 recipe for making up the chemicals, but a simpler recipe has been 

 suggested by Dr. M.E. Saltveit, Jr., formerly at North Carolina 

 State University. It is as follows: "First dissolve 1 level 

 teaspoon of potassium iodide crystals in approximately 1/8 cup 

 clean water in a 1-quart container. Gently swirl the container 

 until the crystals dissolve. Next, add 1/4 teaspoon of iodine 

 and swirl the container until the iodine dissolves. Finally, di- 

 lute this solution with clean water to make one quart. 



This solution is sensitive to light and should be kept in a 

 dark container, such as a glass jar wrapped in aluminum foil. 

 Fresh solution should be made every season." 



The above chart is designed for use on Mcintosh, and the 

 brochure contains an accompanying chart for use with Delicious. 

 North Carolina also has a brochure available with charts for De- 

 licious, Golden Delicious, and Law Rome. ("Determining the matu- 

 rity of North Carolina apples. The starch- iodine staining 

 technique." Publication AG-282). It ws prepared by M.E. Salt- 

 veit, Jr. and Susan A. Hale, Dept. of Horticultural Science, 

 North Carolina State University, Raleigh, NC 27650. 



We strongly urge growers to try the starch- iodine test for 

 apple maturity, and to see for themselves the clear changes that 

 are portrayed by the tests. We believe that the tests will pro- 

 vide information that will make it easier for growers to make 

 wise decisions during a very stressful period. 



POMO LOGICAL PARAGRAPH 



Storage temperature for Mcintosh in CA . The correct temperature 

 for holding Mcintosh in CA is 36-38-F. Growers operating their 

 rooms at less than 36 -F are increasing the risk of low temperature 

 injury, as occurred during the 1982-1983 storage season. Symp- 

 toms of low temperature injury this past storage season were a 

 brownish-gray discoloration around the stem-end of the apple 

 and/or internal browning of the flesh near the core of the apple. 



