North American Fruit Explorers mailing list at ibiblio

["Stephen Sadler" <Docshiva@Docshiva.org>]

Does curculio affect apples?  That seems an extremely difficult pest to deal with. 

 

You’re right about the benefits of having an orchard that is hospitable to beneficial.  Another important principle of organic gardening/orcharding is soil health.  Both those can decrease the need for sprays.  You’re right, too, that just because something is permissible doesn’t mean it’s used; any grower would want to keep cost effectiveness in mind. 

Out here in the far West, organic apples and other produce are priced competitively with conventional.  There are clearly different challenges in different parts of the country, and California’s Central Valley may simply be a good location for organic farming; but I suspect it’s years of familiarity with the methods and good soil maintenance that allow organic growers to compete. 

 

~ Stephen

 

From: nafex-bounces@lists.ibiblio.org [mailto:nafex-bounces@lists.ibiblio.org] On Behalf Of Road's End Farm
Sent: Sunday, April 13, 2008 2:49 PM
To: dmnorton@royaloakfarmorchard.com; North American Fruit Explorers
Subject: Re: [NAFEX] Organic vs Standard Spray Programs

 

Hi Dennis,

I downloaded the actual study, which was linked to in the link you sent. I don't grow apples, so I'm not the best person to comment on this (again, I'd suggest you contact people actually growing organic apples in your state; if I remember a previous discussion on this correctly I found several by googling); but I did notice the following:

First of all, this is not actually a comparison of an organically maintained orchard to a conventionally maintained orchard. The entire orchard was conventionally maintained in the use of fertilizers and herbicides. A number of trees within the block were then, for one year only, given a partially organic spray program as far as insecticides and thinning were concerned (even some of the "organic" insecticide sprays were substances not approved for organic production), while other trees within the same orchard were conventionally sprayed with insecticides and thinners.

Organic growers spent years arguing with Cornell about such "trials" in their vegetable plots.
Cornell finally agreed, and set up a separate organically managed farm. (I don't know whether they have any apples there or not.) The setup used in the study you quoted is the proper setup for experiments involving single-item variables; but organic management is not a single-item variable, it's a whole-field technique, and not just because organic growers are being nitpicky. Much of organic pest management is provided by naturally occurring beneficial organisms. The field as a whole needs to be hospitable to beneficials, and it can take several years for the populations to build up. Beneficials can be affected by soil conditions as well as by the presence or absence of sprays applied above ground in the general area, and so may be affected by growing techniques that do not involve obvious insecticides. Attractiveness of fruit to pests can also be affected by fertilization and other growing techniques.

Another couple of points, less major than the above, but they did occur to me:

-- The size difference in organic fruit was attributed by the study to the use of a thinning spray. I don't know how many organic growers actually use this spray to thin. This would have affected the yield results. (They also may have used too much of it, as they say the organic thinning spray reduced the number of fruit per tree to fewer than the number on the conventionally thinned trees.)

-- I don't know how many organic apple growers actually use this many sprays overall. Because something is listed as permissible doesn't mean that all growers are using it. (Of course, I also don't know whether most conventional apple growers actually use this many sprays, either.) If growers who do have high levels of beneficial insects in practice use fewer sprays, this would affect their cost comparisons. (I bring this up because my experience with vegetable crops is that most organic growers use far less in the way of insecticides than someone looking at a list of possible-use materials might conclude; and because I have seen comparisons of cost or environmental impact which assumed that it was common for organic growers to use repeated applications of materials that in fact many didn't use at all, and most of those who did used less often. Again, I don't do apples, and don't know how the situation compares.)

-- There were clearly varietal differences in results, though I couldn't figure out from the study to what extent this affected the overall results, as varietal differences, as near as I could tell, were given for organic and conventional treatments combined, rather than separately. Choosing the right varieties for the specific farm is an important part of organic technique. There are certainly varieties that can't be successfully grown organically, in any given climate; a fair answer to the question of whether apples can be grown organically in the Northeast, and if so at what cost, would require specifying what varietes were being discussed.

As I understand it, apples are one of the hardest crops to grow organically in this area. However, I don't think this particular study actually proves much of anything on the subject.

--Rivka
Finger Lakes NY; zone 5 mostly