Plant Diseases

No matter how many hours we spend lovingly tending to our plants and gardens, we can’t always protect them. We’ve covered aphids, we’ve covered invasive plants, we’ve even covered weeds that may or may not wreak havoc in the garden, but now we’re delving into the murky world of disease. From time to time, the tell-tale signs will affect the plants of even the most vigilant of gardeners, but it doesn’t have to be all doom and gloom… although sometimes it most certainly will be. Whilst a few simple measures can prevent most diseases reaching our beloved borders, caught early, those that could potentially be more stubborn can be eradicated easily; others, however, can mean the end of some plants and swift removal to avoid transference to others, and there’s a chance the disease could spread to the soil and affect many more plants. A little knowledge really can go a long way to preventing a garden disaster.

        

Whether bacterial, fungal or viral, disease can be spread by us, so good garden hygiene will go a long way to preventing spreading it; washing and disinfecting gloves, hands and tools will help, particularly when handling plants that are diseased, but no matter how thorough we may be, we have no control over the insects that visit our gardens, where infected seeds come from or go to or, indeed, the weather – humidity, cloud and dry conditions are ideal for disease to thrive. Buying disease-resistant plant varieties, wherever possible, is the first step to preventing outbreaks, along with inspecting new plants for symptoms before allowing then into your garden. Be sure to plant new purchases or seedlings far enough apart to allow air to circulate, enabling leaves to dry quicker and preventing the very conditions disease is looking for; staking and regular pruning will also help. Water can play a big part in the control of disease, so along with room for plants to breathe, watering roots will prevent leaves getting wet, giving less opportunity for certain diseases to take hold, and doing so in the mornings will help with water-retention; a mulch around the base will assist further – less watering, less chance for disease. Weak or stressed plants could be more at risk, so following growing instructions is absolutely necessary to ensure enough – but not too much – sunlight, water and feed. Well-draining soil is also a must and appropriate fertilisers will add crucial nutrients to the soil. If disease still makes an appearance, removing and destroying infected leaves and branches – or even the entire plant – quickly will prevent any others becoming infected; compost piles are not the ideal place for diseased plants; removing and destroying means exactly that. Insecticides may be a crucial weapon, but they may be harmful to essential pollinators, children and pets, so care should always be taken; recipes for homemade insecticides that include natural ingredients like garlic, chilli powder or vegetable oil can be found online.

      

Now we know what to do, here are some of the most common plant diseases:

Black Spot
Whilst this particular disease can affect many plants, it’s often found on Roses. The first signs are dark spots on the leaves, but left untreated, it’ll turn them yellow before they fall off. The plant may weaken, making it more vulnerable, and its flowers can also be affected. As the fungus thrives in wet conditions, keeping water away from the leaves – watering the roots, adding a mulch – will help curb its control. It’ll remain in the plant throughout the winter, so removing leaves and stems affected will have a big impact on its survival.

    

Mosaic Virus
Many soft fruit and vegetables can be affected by the Mosaic Virus, including potatoes. It’s recognisable by yellow or green patterns on leaves and possibly leaves that are cupped, curled or distorted in other ways; there may also be stunted growth and a poor harvest. There is no cure, unfortunately, so removal of and destroying the plants affected are the only options available, and with the virus potentially surviving in the ground for many years, it would be best to avoid planting in that particular patch for a while.

    

Powdery Mildew
Another fungus, Powdery Mildew appears as a white, powdery dust on plants, and it, too, flourishes with humidity; dry conditions, however, won’t necessarily eradicate it. It can affect many plants, including fruit and vegetables, taking advantage of those tightly packed together with poor circulation, so adequate spacing between plants is key to preventing it taking hold. Water at the roots, again, and any part of the plant affected should be removed and destroyed.

  

Rust
There are several species of this fungus that affect different plants and trees, but unlike other diseases, it’s less harmful; its effects are mostly aesthetic. Appearing as orangey-red or brown spots, it can affect fruit trees and plants. Removing affected parts of the plant should be enough to stop its spread, and as it’s another that likes to overwinter on its host, doing so before the winter should prevent its return.

    

Grey Mold
A sooty fungus that develops on dead or dying plants, it can spread to healthy plants in wet conditions. Again, both flowers and fruit can be affected, but spread can be prevented by removing and destroying the dead parts of affected plants, taking care to avoid spreading spores by mulching the soil.

    

There are many more diseases that can affect your garden, and many more still that are plant-specific, so it’s not possible to cover them all in a single blog post, but if you have any concerns about any plant, speak to one of our experts and deal with it as soon as possible. Early action is key to happy plants and a happy gardener, and we all just want to be happy, don’t we?