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Articles on Holistic Orcharding

The Kaolin Clay Strategy for Orchards

Thorough coverage with the refined kaolin clay keeps fruit-eating pests at bay -- photo: Michael Phillips.
Thorough coverage with the refined kaolin clay
keeps fruit-eating pests at bay.

Surround kaolin clay spray has given organic orchardists an effective tool for an array of petal fall pests that destroy fruit when it's the size of a marble. Yet, as always, a good thing can be overdone. Understanding the nuance and the timing of this barrier spray strategy makes a reasonable harvest possible.

Good Research

Work done in the 1920's and 1930's with pottery-grade kaolin proved unsatisfactory, as plant health suffered and insects still maneuvered through the large (relatively-speaking) clay particles. Enter in soil scientist Mike Glenn of the USDA Appalachian Fruit Research Station with an idea to use refined kaolin for orchard disease control. A drastic reduction in insect damage at petal fall was noted as a result. Horticultural benefits have followed from there. Disease control remains elusive, as the formulation is not hydrophobic.

Surround: A Corporate Product

A super-magnetic centrifuge in Georgia is used to refine the impurities out of raw kaolin and then filter the clay particles to a critical 1.4 microns in size. Only corporate money can achieve this, and that makes for a patented product that costs what it costs. Take note: Pottery grade kaolin will not work like Surround has been designed to work.

Kaolin particles make life less than pleasant for fruit pests like this pear psylla. (photo: Michael Glenn, USDA Appalachian Fruit Research Station)
Kaolin particles make life less than pleasant for fruit pests like this pear psylla. (photo: Michael Glenn, USDA Appalachian Fruit Research Station)

The Petal Fall Complex (Timing)

Orchardists in the East face three devastating pests at about the time the blossom petals begin to fall from the trees en masse. European Apple Sawfly begins laying its eggs while pollinating the white apple flowers: The successive instar stages of its young wipe out 3 to 4 fruitlets per larvae. Plum curculio (long called the Achille's heel of organic orcharding) waits for warm evenings when females begin laying 4 to 5 eggs per day and both males and females make feeding stings. Codling moth egg hatch begins about ten days after petal fall, completing this triad of potential devastation. Full coverage of Surround needs to be built up at initial petal fall for best results with all three insects.

The larva of obliquebanded leafrollers (OBLR) feed on developing apples and tender leaves alike. (photo source: West Virginia University Fruit Web). more insights:
The Lepidoptera Complex

Three Coat Effectiveness

Surround serves in one of two ways as an insect repellant. Just imagine your eye and ear openings filled with irritating clay particles, and your reproductive parts literally clogged . . . surely you'd want to boogie from such a place! This is the experience of insects like curculio that crawl about the twigs and leaf surface seeking fruitlets. Flying insects don't get quite the same experience, flitting about to lay an egg here and there. Upon landing on a kaolin-coated tree, the codling moth female senses a wrong environment and continues on.

This next point cannot be over emphasized: Surround proves effective only once 3 uniform applications have been made. There's enough clay at this point to actually stop the early instar stages of sawfly larvae from going much beyond the winding scar trail of its first apple. One coat of clay is simply not enough coverage to actually deter the insect's normal inclinations. Make back-to-back applications to get to this launching point of successful orcharding. Coverage then needs to be maintained weekly for approximately four weeks. Heavy rain may necessitate additional applications.

Grow your orchard library at our Bookshelf Grow your orchard library at our Bookshelf.

Spray Rates

Label instructions recommend a rate of 25# to 50# of Surround per acre per application. Whether you mix this in 50 gallons of water or 200 gallons of water is determined by sprayer type and the size of the trees on your acre. Coverage needs to be applied to the point of runoff and allowed to dry. A sticker-spreader isn't necessary, and in fact, experiments with vegetable oils to improve kaolin's holding power have decreased efficacy. These particles have been engineered specifically to come off readily onto the crawling insect! The coverage provided by a hand-held wand spray rig is often superior to an air-blast sprayer simply because you take more time per tree to achieve a full coat. Home orchardists with a backpack sprayer can figure on using 1/4 to 1/2# per gallon of water, gauging the coverage more by point of run-off than by a hypothetical amount per acre. Surround stirs best into the water as opposed to pouring water into the dry powder. Agitation in the spray tank should keep sediment from clogging the pump . . . backpackers may need to jump about a bit!

Surround Apple: Western growers use Surround primarily to prevent sunburn.
Western growers use Surround
primarily to prevent sunburn.

Enhanced Photosynthesis

Lessening of sunburn, increased fruit size and better color, and even improved return bloom are among the claims made for Surround. But all these benefits aren't necessarily going to come about in northern zones with shorter growing seasons.


Prolonged kaolin coverage is harsh on mite predators. Overdo this spray strategy and you'll likely induce a red mite flare-up, which will necessitate returning to using dormant oil sprays prior to quarter-inch green. Don't be tempted to continue kaolin coverage for second-generation moths and apple maggot fly! This petal fall tool falls out of balance as regards beneficials if coverage is maintained too long. Plus then the problem of residues at harvest time is a major, major headache.

Adapted illustration by John Bunker, FEDCO Trees -- click for Holistic Orchard Research home page Check out the latest in Holistic Orchard Research

Trap Tree Rationale

Some orchardists have observed that curculio seems to wait out the coverage. That four weeks should perhaps be six or more weeks of coverage. The problem arises when we ponder the options for curculio. A complete whiteout of their environment leaves little choice but to wait for improved opportunity. Surround repels; it doesn't kill. A wise orchardist will select a trap tree or two, or leave some unsprayed wild trees in the proximity. We truly need to learn that there's a place for all species on this good earth if we want to reach that next plateau of sound thinking. Which doesn't mean plummeting curc larvae can't be met by a waiting chicken flock pecking away down on the ground!

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Explore even more nuance in our grower discussion forum.


Gardens Alive sells 5# quantities of Surround labeled for home use at about three times the going trade price. Be smart with your money and get the 25# bag: kaolin keeps for years, so even if you have only a tree or two to protect, you're supplied for several seasons. Seven Springs Farm in Virginia has the best mail order price going: See Northeastern growers should check with Organic Grower Supplies in Maine: all the FEDCO cooperatives offers substantial discounts based on order volume. United Ag Products also distributes Surround in its regional warehouses serving commercial orchard areas.


Organic Orcharding Articles

bar stripe
bar stripe is a Holistic Orchard Network: Together we can Grow Organic Apples as part of the local foods movement. btm

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