to be related to the difTerences in cropping between 

 these treatments. Neither fertilizer affected leaf or 

 fruit mineral nutrient content, fruit size, or fruit 

 firmness at harvest (data not presented). 



Russeting is a rough brown netting over the 

 surface of the fruit that occurs when the fruit epider- 

 mis is killed. Ciolden Delicious is an economically 

 important cultivar that is predisposed to russeting, 

 while Delicious is much less sensitive to russeting. 

 Russeting results in loss of grade when fruit are 

 packed and must be kept to a minimum if an orchard 

 is to remain profitable. Fish hydrolysate increased 

 fruit russeting on both cultivars (Table 1). The 

 conductivity of the fish hydrolysate fertilizer was 

 45.6 mmhos/cm, the equivalent of a 29,000 ppm 

 solution of KCl. It is probably this salt that reduced 



fruit set and caused the severe russeting. Regard- 

 less of the cause, fish hydrolysate reduced fruit set 

 and damaged the fruit and should not be foliarly 

 applied to apple. 



Literature Cited 



DeMoranvUle, C. 1990. Fish hydrolysate fertilizer : 

 its potential role in commercial cranberry produc- 

 tion. HortScience 25:626 (abstract). 



Stiles, W.C. and W.S.Reid. 1991. Orchard Nutrition 

 Management. Cornell Coop. Ext. Bui. 219. pp. 18-19. 



Weis, S.A. and W.J. Bramlage. 1992. Using fish 

 waste hydrolysates as a fertilizer for apples and 

 blueberries. Fruit Notes 57(3):15-19. 



•Im %t^ «£• •!# 9^0 



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Comparative Effects of Margosan-0 

 (Neem Extract) and Imidan on Plum 

 Curculio and Apple Maggot 



Ronald J. Prokopy and Margaret Christie 

 Department of Entomology, University of Massachusetts 



John Bemis 



Hutchins Farm, Concord 



We are continually on the lookout for safe new 

 pesticides that can control some of our key apple 

 pests, such as plum curculio and apple maggot. 

 Extracts of seeds and other parts of neem trees have 

 been used for centuries, even millennia, to control a 

 wide variety of insects in India and other parts of 

 Asia. These extracts appear to be remarkably safe 

 for human consumption as well as environmentally 

 safe. They are known to control insects by acting as 

 insect repellents, antifeedants, or toxicants or by 

 disrupting the growth of insects. Recently, W.R. 

 Grace Company began distributing an extract of 

 neem plants called Margosan-0 for use in green- 

 houses, commercial nurseries, forests, and homes. 



Although no extract of neem, including 

 Margosan-O, is yet registered for use on crops for 

 human consumption, we decided to evaluate its 

 eflFectiveness against plum curculio and apple mag- 

 got on apple trees at Hutchins Farm in Concord, MA 

 in 1992. Hutchins Farm grows produce organically 

 and annually contends with moderate to high popu- 

 lations of plum curculio and apple maggot. 



Methods Used 



Against plum curculio, a treatment of 

 Margosan-0 at one gallon per 100 gallons was ap- 

 plied with a mist blower at 300 gallons of water per 



18 



Fruit Notes, Spring, 1993 



