Every fruit grower wants a bountiful harvest, but plant diseases can quickly turn that dream into a nightmare. Fire blight, caused by the bacteria Erwinia amylovora, is a serious threat to apple (Malus spp.) and pear (Pyrus spp.) trees worldwide. In this fifth blog entry, David Haddad (Horticulturist and business owner) dives into everything apple and pear growers need to know about Fire Blight, from its history and spread to identification, treatment, and prevention methods.
A Growing Threat to Plant Health
Erwinia amylovora was the first bacterium to ever be described as a “causal agent” of a plant disease, Fire Blight. The bacteria and disease had been identified previously, separately, but the connection had never been made. This bacteria has been targeting the Rosaceae (Rose) plant family, in particular apple and pear trees, since its discovery and classification in the late 1800s. First reported in North America in 1883, with the UK reporting its first outbreak in 1957. However, its reach has expanded dramatically from 15 countries in the world reporting cases in 1977 to 46 today.
Beyond Apples and Pears
While apple and pear trees are the primary targets, fire blight can also infect loquat, quince, hawthorn, raspberries, and some common UK ornamentals such as Cotoneaster and Pyracantha.
Importance of Staying Vigilant
As highlighted in my third entry in this blog series, rising global temperatures caused by Climate Change is making it easier for the bacteria to thrive in previously unaffected areas. In the US, Michigan and Washington states remain hotspots for Fire Blight, while Europe and the UK see outbreaks during warmer, wetter months.
It’s important to be vigilant, especially if you have a variety of plants in your garden or orchard. Every plant, tree or crop has a set of needs to ensure optimal growth; an unhealthy or unhappy plant is susceptible to disease. If you are a novice fruit grower, make use of online resources to learn more about what diseases your plants/trees may be susceptible to – every disease develops and presents differently.
Identifying the Erwinia Enemy
Early detection is crucial for managing Fire Blight.
- Browning: New growth, flowers, and the tips of shoots will turn brown and begin to curl.
- Die-off: Infected branches and entire sections of the tree can die and turn brown, as if scorched by fire.
- Oozing: Sticky secretions may appear on leaves, stems, flowers and/or fruit.
E.amylovora bacteria are able to survive in the bark of cankers (dead sections grown over wounds in the tree) through the winter, and “come alive” again in the Spring. Wet winters and regular irrigation can unintentionally help to keep the bacteria alive during winter.
Diagnosis Made Easy
Gone are the days of relying solely on visual cues or waiting for confirmation from the lab, with the Pocket Diagnostic® Erwinia amylovora lateral flow test (available online for £23 for 4 tests) you can diagnose a Fire Blight infection in minutes. These portable easy-to-use kits, are provided with all necessary components allowing testing to be completed within the field, with no training required.
Early detection empowers you with fast decision-making, allowing immediate implementation of recommended treatment & isolation protocols to be initiated.
Combating Fire Blight
Treatment options are limited, but there are treatment protocols being used to help isolate and kill the bacteria:
- Pruning (recommended): Remove and destroy infected branches using sterilized tools. This helps prevent further spread. Be very careful when disposing of the infected plant material, and never use infected material to make compost.
- Antibiotics: Commercial growers may use targeted antibiotic treatments on infected areas of the trees. Preventative copper and antibiotic sprays are used to control the population of bacteria on the surface of the plant, and in-turn can help prevent infection through wounds.
- Heat Treatment: Heat treatment (thermotherapy) can be used on cuttings for propagation to eliminate potential infections. Plants can carry (and pass on) the bacteria for a while without showing any symptoms.
Prevention is Key
The best defence is a good offense. Here are some proactive measures you can take:
- Monitor Regularly: Inspect your trees frequently for signs of disease. A quick test from Pocket Diagnostic® can confirm your suspicions.
- Choose Resistant Varieties: Select apple and pear varieties known for their resistance to disease. Sadly, the classic British apple varieties such as the Pippin and Russet are dying out due to a rapidly changing climate and being replaced with Japan’s Fuji apple and New Zealand’s Gala apple.
- Cultural Practices: Proper pruning techniques, good air circulation between trees and foliage, and avoiding excessive fertilization can all help reduce the risk of infection.
- Hygiene: Sterilize pruning tools between cuts to prevent spreading the bacteria.
Remember, a healthy fruit harvest starts with healthy trees!
Embrace Technology for Improved Plant Health
New technology like rapid testing is bridging the gap for everyone who cultivates greenery, from seasoned gardeners to urban farmers. Take Fire Blight, a nasty bacterial culprit caused by E.amylovora. Previously, pinpointing such diseases might have felt like a mystery with access to laboratories needed, but with the Pocket Diagnostic® rapid test range, understanding plant enemies like E.amylovora becomes accessible, and less of a mystery. These rapid tests are user-friendly, affordable, and require no prior training. Invest in these innovative tools to empower yourself with on-the-spot diagnoses. By embracing technology like rapid testing, you can optimize your crop yield and protect your precious plants from preventable losses. Learn more about how rapid testing can help protect your crops at www.pocketdiagnostic.com
We’re All in This Together
There’s a common misconception that understanding and managing plant diseases is solely the domain of large-scale farmers and scientists. The reality is that plant diseases can easily spread from garden to garden – and country to country – posing a threat to everyone’s harvest. By educating ourselves about the signs of Fire Blight and having the tools for detection readily available, we can all play a part in controlling its spread. After all, a fruitful harvest often hinges on early detection of disease. Don’t let Fire Blight steal your harvest – knowledge is the best weapon in this battle!