Bagging Little Green Apples

A post on: www.botanicalgarden.ubc.ca/blog/bagging-little-green-apples

Submitted by katie on Wed, 08/26/2015 – 12:38

Earlier this summer we caught up with Richard Hallman, one of our workshop instructors to ask him about his work and why he was bagging apples. If you are interested in learning more about Tree Fruit Horticulture Richard is teaching Fall Fruit Tree Pest & Disease Control on September 26, 2015.

In Richard’s own words: 

The most destructive and frustrating insect pest of apples and pears in the Vancouver area are Codling Moth and Apple Maggot, the worms in our fruit. The Codling Moth adult is a moth that was introduced to BC from Europe in the early 1900’s. Apple Maggot adult is a fly that moved across the border from Washington State in 2006. Organic management of these two insects is difficult and often unsuccessful.

Codling Moth adults started emerging in the Vancouver area during the last half of May this year and Apple Maggot adults are now emerging as well. One of the most successful ways to prevent damage from these insects in home gardens is the use of exclusion bags and the UBC Botanical Garden is using a few this year on trial. Usually a small mesh bag is pulled over the small fruit and firmly tied to the stem. The first image attached to this post is of a bag newly installed. These bags protect the fruit from the insects and they expand with the fruit providing season long protection (see the second image). Installing these bags is a lot of work, a manageable job if your trees are small.

An alternative to using these mesh bags is to use Japanese Apple Bags to protect the fruit. These are double bags, an inside bag of rice paper and a outside bag of heavy paper. These bags were developed in Japan to improve the appearance of the fruit. These bags are only used on apples that ripen in late September to early October and are red at harvest. Chlorophyll (the green color) usually develops in apple fruit exposed to sunlight, inside these bags the apples are white or pale yellow. About 10 days before harvest the bag is taken off the fruit and a dark colored graphic is attached, then the rice paper bag is put back over the fruit to prevent sunburn. This late in the year there is not enough time for chlorophyll to develop so when anthocyanins (the red color) start to develop stimulated by cooling temperatures the color that results is a bright red rather than the usual dark red. At harvest the rice paper bag and the graphic are removed and you have a insect free bright red apple with a custom graphic. The above images are of a project using these bags in the Creston Valley.

Richard Hallman is the UBC Botanical Garden Fruit Tree Expert in Residence

 

Tree of 40 Fruits

Over the last few months the “Tree of 40 Fruits” has been trending all over the internet and traditional media. Here is the Smithsonian Magazine article about this tree and the person who developed it, Sam Van Aken. Here is Sam Van Aken’s own page and here is a YouTube Video about it. There have been lots of stories about this tree some simply amazed and some calling it a hoax. It is not a hoax, The techniques that Sam Van Aken used to create the many “Trees of 40 Fruits” that he has made are the same techniques that nurseries and orchardists use to create the tree fruit planted in gardens and orchards around the world. His trees are based on the graft compatibility of most types of plums, apricots, peaches, nectarines and almonds. He has done a nice job of researching blossom colors and the relative dates when each cultivar grafted on his trees to design a tree with many colors of blossoms that should bloom for a few weeks in most climatic zones. And then there is the multi colored fruit and prolonged harvest from early summer into the fall. Great job well done!

Espalier Fruit Trees – Forms

UBC Espalier Apple

UBC Espalier Apple Summer

The classic espalier form is the Horizontal Espalier (also call the T-Espalier or Horizontal Palmette or Cordon Ferraguti). Many people I have met think this is what “Espalier” means. This is not the easiest espalier form to create, especially if you are looking for perfect geometric form with each set of horizontal branches being attached exactly opposite each other. Temperate fruit trees do not

Horizontal Espalier UBC Botanical Garden winter

Horizontal Espalier UBC Botanical Garden winter

have buds growing opposite one another, the skill of the espalierist is demonstrated by how close to directly opposite these branches are. Pears and apples are most commonly grown in this form. Plums, cherries, apricots and many other trees can be growing as Horizontal Espaliers. This tree is in the UBC Botanical Garden.

The University of British Columbia Espalier Fruit Tree Collection

The term espalier originally meant a two dimensional tree trained flat against a wall. The term has changed in most countries around the world to include a wide range of two and three dimensional forms. Espalier training of fruit trees fascinates me. My backyard is full of fruit trees and bush fruits trained to grow in a wide range of patterns. Recently I started working with the University of British Columbia Botanical Garden to

UBC Espalier Apple Trees

UBC Espalier Apple Trees

rebuild their espalier fruit tree collection. At one time this collection was world class, recently canker infected apple trees resulted in many tree being removed. Plans are developing to rebuild this collection with trees that are suitable for our West Coast (NA) climate and can be espaliered. Follow my posts over the next few months to follow the redevelopment of the collection back to amazing. UBC Apple Trees in summer.

Summer Heat and Bitter Pit

The unusually hot summer temperatures that we have been experiencing on the West

Sunburn of Apple Fruit

Sunburn of Apple Fruit

Coast is stressing our fruit trees. I have seen sunburn on leaves and fruit similar to the type of damage that is common in the hot dry areas of the interior. When temperatures rise to 35+ degrees C this type of damage happens quickly to exposed fruit and older leaves.

Of more concern for apples is the development of Bitter Pit. This is a temporary Calcium deficiency induced my drought. The BC Ministry of Agriculture has an excellent information page about this

Severe Bitter Pit of Apples

Severe Bitter Pit of Apples

problem: Bitter Pit. The way to avoid this problem is to provide your trees with consistent adequate soil moisture. The damage is usually concentrated on the calyx end of the fruit and it will be worse in very large fruit and on young fast growing trees. Excess pruning and applications of too much nitrogen will aggravate this problem.

If you have one of these problems and willing to share please send me some images.