The first sign of branch canker and dieback is reddish sap that dries to a white powder. If you grow avocados or pears, you should know what else to look for and how to respond.
 
Formerly known as Dothiorella canker, this fungal disease is caused by several different fungi. Most are in the Diplodia genus, along with Kalmusia variispora, Eutypa lata, and Neofusicoccum parvum.
 
Symptoms of branch canker and dieback
 
Identifying the problem is your first step in saving your trees. Unfortunately, I couldn’t find any usable images. Symptoms of branch canker and dieback include the following:
 

• Branch cankers
• Cracked, discolored, or sunken bark
• Dead spurs
• Dieback above the graft union
• Leaf flagging
• Leaf scorch
• Pruning wound lesions
• Reddish brown to brown inner bark
• Shoot blight
• Stem end fruit rot
• Swollen graft unions

 
Leaf flagging refers to leaves that die quickly but remain attached to the tree.
 
If you cut off an infected branch, you will see a wedge-shaped canker that reaches the xylem. In branch canker and dieback, these discolored areas can penetrate deeply into the wood, allowing fungal spores to spread into other parts of the tree. Phytophthora trunk cankers are more shallow. That said, many trees can live with branch canker and dieback, while Phytophthora trunk canker is a more serious disease.
 
Older trees may be able to withstand a branch canker and dieback infection, but young trees often cannot. If the disease girdles the main trunk, it can kill mature trees.
 
Branch canker and dieback often takes hold after a tree has been damaged by fire blight, sunburn, or sloppy pruning. Clean cuts and sharp tools help keep your trees healthy. Trees suffering from nutrient deficiencies, drought, improper irrigation, and insect and mite feeding are also more likely to become infected. Fungal spores travel on breezes and in rain and irrigation splashes.
 
Managing branch canker and dieback
 
Good cultural practices, sanitation, and investing in certified pest- and disease-free bare root stock and other plants are the best ways to prevent branch canker and dieback. Once the disease occurs, use the following tips to minimize its effects:
 

• Prune out infected twigs and branches, cleaning your cutting tools with disinfectant between each cut to prevent further infection.
• Discard infected plant material in the trash.
• Only work with your trees when they are dry.
• Do not allow sprinkler spray to hit tree trunks.

 
Get outside and take a closer look at your trees. The more familiar you are with them, the more quickly you can spot and respond to problems.
 
Walking among trees, out in nature, is a good way to take care of yourself, too.

Tayberry description
 
Tayberries (Rubus fruticosus x R. idaeus) are cone-shaped accessory fruits that grow on shrubs. Some varieties are thornless, while others are nearly thornless. Those thorns are tiny and sharp, so it is a good idea to wear gloves when working your tayberry canes.

Tayberry fruits can be up to 1½ inches (4 cm) long and are available from early to late summer. These fruits tend to be red and very soft, so pick gently. Tayberries are like blackberries in that the torus or core stays with the plant when the fruit is picked.
 
Tayberry roots and crowns are perennial. Canes grow 6 to 7 feet (1.8 to 2.1 m) long. Like other brambles, first-year canes (primocanes) do not produce fruit. The second-year canes, they become productive floricanes. Once a cane has produced fruit, it is done and should be removed. This is an excellent way to reduce the chance of disease. It makes harvesting easier, too.
 
How to grow tayberries
 
Tayberries need full sun and good drainage. They grow best in loose soil, rich in organic matter. (Don’t they all?) Tayberries grown in soggy areas will have problems, but you will want to be able to irrigate your tayberries during the growing season to get the most out of your plants. It’s a juggling act, but worth the effort.
 
Also, your tayberries will be more productive and easier to manage if they are trellised. This improves air flow, reducing fungal disease, and makes it harder for pests to hide.
 
Bramble fruits grow best in soil with a pH of 5.8 to 6.2. Before planting, getting your soil tested to see what is present and what needs to be added. Generally speaking, bramble fruits need 2.5 pounds (1.1 k) of nitrogen, phosphorus, and potassium per 1000 square feet. A little extra potassium in late summer will help plants get through the winter and have a strong start in spring. As always, it depends on what is already in your soil so get it tested.
 
You may also want to plant a cover crop, such as buckwheat, millet, oats, or rye to prepare the soil and set the stage for tayberry success. A top dressing of aged manure or compost can supercharge the soil and help your tayberries thrive.
 
Once your planting site is ready, canes are best installed in mid-October. Be sure to invest in certified pest- and disease-free tayberry crowns.
 
Tayberry pests and diseases
 
Aphids, Japanese beetles, sawflies, and spider mites are common pests of tayberries.
 
Being a hybrid, tayberries are disease-resistant, especially to late yellow rust, but anthracnose, leaf spot, root rot, and orange rust can still cause problems.
 
Tayberries should not be grown  where members of the nightshade family have been grown in the last four years due to a higher likelihood of Verticillium root rot. Your tayberries will be healthier if they are at least 600 feet (180 m) away from wild bramble plants. This reduces the chance of viral diseases spreading to your crop.
 
These plants can tolerate temperatures as low as -15°F (-26°C) and are hardy to USDA Planting Zone 6.
 
Harvest your tayberries as soon as they are ripe to keep your plants producing. If you have more than you can use fresh, you can always cook them down into preserves or try your hand at making tayberry wine or beer.