Organic Apple Production at NSO

(by Ike Kerschner, spring 2018)

I have been fascinated by the possibility of growing fruit organically for decades. 35 years ago, the main chemicals used in fruit production were organophosphates and broad spectrum fungicides, so I felt growing organically would be a gentler means of fruit production. I learned quickly, back in the early 90s when we started NSO, that growing organically wasn’t so easy. As a funds-challenged 27-year-old, I decided I didn’t have the resources of time or money to risk a commitment to organic production.

Since then, I have learned, experimented, and grown a lot of mindfully-sprayed fruit, trying to strike a sensible balance between organic ideals and practices with the need for conventional chemical intervention.

Available conventional chemicals have improved dramatically over the last decades, becoming in most cases safer for people and planet as well as targeting specific problems rather than everything all at once. Organic production still fascinated me, however, so starting in 2013 I felt the resources were available to make a serious effort at organic apple production here at NSO.

We planted a ⅕ acre block in an isolated location on the farm in the spring of 2014 with a wide range of varieties so I could learn which would perform best under my organic production practices.  

In 2016 we had a few fruits from the block, and last year (2017), we had enough to start selling them. Due to limited availability, we decided to focus marketing the organic apples at the West Chester Growers’ Market only. In this way, we could offer a weekly supply of various varieties and see what the customer response was. In the foreseeable future, we will continue to sell the organic apples (in addition to our regular, IPM-grown, apples) to customers at the West Chester Growers’ Market, rather than sending lesser amounts to other markets. At West Chester, the organic apples are labelled as well as displayed separately from the rest of the fruit for sale.

We found last year that, as anticipated, those customers who felt strongly about buying organic gravitated solely to the organic apples. But most customers ended up buying a mix of organic and our regular (IPM) fruit...especially as we offered different varieties in organic vs. IPM.


Deciding upon which varieties to grow organically was made keeping the following factors in mind:

1. The variety should have good fresh-eating quality (we are, after all, growing to eat it and not just look at)

2. The variety should have good disease resistance. In the Mid-Atlantic climate there are a number of diseases and insects that can decimate an apple crop. But there is very little in the way of useful insect resistance in modern apple varieties.

There are four main diseases of apples in the Mid-Atlantic region (known as “the big 4”): scab, rust, powdery mildew (PM), and fire blight(FB). There is also one disease complex (the summer fruit rots, white rot, black rot and bitter rot), and a group of minor diseases that are incidentally controlled when the main diseases are controlled but which may emerge as major problems when disease management systems are changed, and there are some minor so-called cosmetic diseases (namely sooty blotch and flyspeck). I say so-called because although they are traditionally considered ‘cosmetic’ diseases (and only, therefore, impacting the appearance of the fruit), these diseases actually can interfere with photosynthesis, can cause apples to dehydrate rapidly in storage, and, if severe, can impart a moldy flavor to the fruit.

An often overlooked impact of disease management is that it helps the tree retain healthier foliage longer which aids photosynthesis which is, of course, where the goodies that make apples so delicious come from. So a good disease management program on organically grown apples is imperative. Even when planting disease-resistant varieties, a significant intervention with organically-approved fungicides is required to produce profitable high eating quality crops of organic apples.


What follows is varieties we have grown, are newly planted, and also those which have already been discarded from the organic apple block:

1. The heirloom group: Mostly older varieties which have proved their merit over time by providing fruit on southern hill farms with little management. This group also contains some modern varieties which do not have single gene scab resistance, although they are tolerant of scab (not super-susceptible) and they have varying levels of resistance to other diseases.

In approximate order of ripening, from earliest to latest, we planted the following heirloom group varieties:

Thompson Early
Beverly Hills
William’s Favorite (removed as it was mosaic virus infected, and had very poor fruit quality)
Bevan’s Favorite
Aunt Rachel (removed as it was too large, and of poor fruit quality)
Early Blaze
Mollies Delicious
Kandil Kitaika (removed...inedible crab apple)
Clivia (removed due to very poor fruit quality)
Grimes Golden
Royal Limbertwig (removed due to cracking and rotting, plus XL fruit size)
Hardy Cumberland
Winter Blush (removed due to poor fruit quality and the fruit drops as it ripens)
King David
Gala Supreme
Brushy Mountain Limbertwig
Prairie Spy
Kinnard’s Choice
Lyon (removed due to soft texture and overall so-so fruit quality)
Myer’s Royal Limbertwig
Black Twig
Arkansas Mammoth Black

2. The modern group: Developed in the last 50 years, including newer varieties from breeding programs which were selecting for disease resistance. They all have single gene scab resistance and varying levels of other resistances. Some perform well in low-spray/organic production systems and others not so well.

In approximate order of ripening, from earliest to latest, we planted the following modern group varieties:

William’s Pride (removed due to bitter pit and chalky flesh characteristic)
Resi (removed due to generally poor fruit quality)
Nova Ez Gro (removed due to generally poor fruit quality)
Belmac (removed due to so-so fruit quality and susceptibility to summer rots)
Sugar Snap
Eclipse (removed for rough appearance and so-so fruit quality)


3. The following varieties from our own on-site breeding program (except Margil) were added to the planting in spring of 2017 or fall of 2017:

(FB resistance has not been tested but has not been observed unless noted)

Superba- resistance to the big 4
Diadem- resistance to the big 4, but susceptible to some summer rots
Bellatrix- presumed resistance to big 4, and very susceptible to phytophthora
Capella- believed scab and rust resistant, very susceptible to PM
Margil- scab tolerant
Polaris- believed resistant to the big 4, but may have some rust and burr knot susceptibility
Tabit- resistance to the big 4, but may have some rust and PM susceptibility
Wasat- excellent resistance to all diseases in our area except sooty blotch, flyspeck, and marssonina blotch
Rasalas- resistances not yet determined
Fafnir- resistances not yet determined, very susceptible to PM
Peacock- resists scab, PM, and leaf spot, but susceptible to rust and FB
Electra- susceptible to scab, rust and burr knots


How is the project going overall? I still have a lot to learn to improve the amount of marketable fruit, although it is going better than I had expected. However, it does need to get better in order for it to remain a viable option.