Plant diseases 101: pest identification, solutions, and prevention

Is your garden starting to show strangely shaped leaves and discoloured plants? Sounds like you have a case of a fungus or disease. Our pest control experts are here to arm you with knowledge on common plant diseases, and solutions. Explore our guide and let’s tackle those pests!

Disarm plant diseases like a pro

Depending on your province, or whether you are experiencing colder or warmer seasons, your garden may be more prone to certain plant diseases than others. This has to do with rainfall and moisture content in your soil. We have provided some of the more likely common diseases, their symptoms, and product solutions you can use. Be sure to reference our directions on how to safely and correctly use each product. You can find this information on our product pages online and in each product insert.

Common fungi found in the garden

Black spot

You can identify this disease by the black spots with yellow borders on older leaves. The yellowing leaves will eventually fall off. To treat this disease, continue weekly spraying until the fungus is controlled — we advise preventative solutions.

Our solution: Efekto Virikop, Efekto Funginex, Efekto Rosecare 3, Efekto Rosecare® Plus

Bacterial blight

Often beginning as small, angular, ‘water-soaked’ spots. As plant tissue dies, leaves turn yellow and then brown. The spots darken, circled by yellowish-green halos. This type of disease occurs on leaves in the mid to upper canopy but is sometimes found on ground plants.

Our solution: Efekto Virikop

Bacterial spot

You can identify this disease by its sometimes water-soaked circular areas. Spots may initially be yellow-green, but then they darken into a brownish-red as they age. In some severe cases, leaves yellow and die. It mostly affects pepper and tomato (members of the nightshade family). 

Our solution: Efekto Virikop

Brown patch

This lawn disease causes grass blades to pull loose easily from the runners, ultimately causing the lawn to die in circular areas. It first begins as small spots in the lawn, then spreads into larger circles or free forms, weakening the turf but rarely killing the grass.

Our solution: Efekto Lawn Fungicide 500 EC

Dollar Spot

This disease mainly occurs on higher mown turf. The name comes from the sunken, bleached, straw-like circular patches that are up to 5 cm in diameter on turfgrass. It is most active during conditions with moist, warm days and cool nights.

Our solution: Efekto Lawn Fungicide 500 EC

Downy mildew

Noticing the upper portion of leaves beginning to discolour, while the bottom portions develop white or grey mould? These symptoms stem from fungus-like organisms. Downy mildew often occurs during wet weather and affects many garden plants and edibles (namely impatiens, pansies, grapevines, lettuce, broccoli and cauliflower). 

Our solution: Efekto Virikop

Leaf curl

You can tell right away if your plant has leaf curl. Leaves will emerge twisted from the bud. Then when leaves start to develop, they become increasingly distorted, turning thick and rubbery, changing from green to red and purple, until a whitish bloom covers each leaf. Leaves then dry, turn black and fall off. This disease affects peach, nectarine and almond trees (some stone fruit orchards).

Our solution: Efekto Virikop

Powdery mildew

A greyish-white powdery growth that develops on younger parts of plants. In the long term, it will cause stunting and shrivelling of leaves.

Our solution: Efekto Funginex, Efekto Lawn Fungicide 500EC, Efekto Kumulus WG, Efekto Eco Fungimite, Efekto Rosecare 3, Efekto Rosecare® Plus

Root rot diseases

Poorly drained soil or prolonged wet weather can lead to the development of root rot diseases.  When the soil becomes waterlogged, weakened roots are more susceptible to soil fungus — another cause of root rot. The fungus may be present but dormant in the soil and the spores can come to life, attacking roots. They eventually rot and die. Citrus and avocado trees can be particularly susceptible. Symptoms include stunted or poor growth; small, pale leaves; wilted, yellowed, or browned leaves; branch dieback; and thinning in the canopy. On some plant species, the fungus grows from the roots in the inner bark causing cankers or sunken dead areas.

Our solution: Efekto Virikop (apply it onto the stems of trees and soil when the diseases appear).


Seeing red to brown raised spots, usually on the undersides of leaves? Rust disease is caused by a fungal parasite (lives on plants to survive). This disease occurs usually in mild, moist conditions. Rust spreads by spores from infected plants to healthy plants. Look for white, slightly raised spots on the undersides of leaves and stems to monitor for signs of developing rust. Rust also causes premature defoliation — affecting mostly beans, strawberries and roses.

Our solution: Efekto Funginex, Efekto Kumulus WG, Efekto Virikop, Efekto Eco Fungimite, Efekto Rosecare 3, Efekto Rosecare® Plus


This sneaky disease first appears as pale, yellow spots on leaves. Then these spots turn into dark, olive-coloured spots on leaves, fruit, tubers and occasionally stems. Flip leaves over and sometimes there will be a velvet-like, fungal growth. Affected leaves may also twist, pucker, turn yellow, and then drop prematurely. Scab often affects apples, crabapples, cereals, cucumbers, peaches, pecans, and potatoes.

Our solution: Efekto Virikop

Expert recommended solutions

In addition to the recommended solutions above, we have a whole range of specially made products designed to assist your pest control needs. 

Efekto Funginex

A fungicide that controls cases of powdery mildew, black spot and rust on various garden plants, as well as powdery mildew and rust on several edible veggies.

Efekto Eco Fungimite

A combination low toxicity solution designed to control fungus and some mites and thrips in various home garden veggies only. It is a great preventative and curative solution.

Efekto Kumulus WG

A granular solution designed to treat fungus and certain mites and thrips on various listed veggies. We also recommend this solution for pernicious scale on dormant roses. This solution can be used on veggies such as avocado, papaya, citrus, apples, pears, peaches, plums, apricots, grapevines, beans, tomatoes, cucurbits, peas, garden plants and roses.

Efekto Lawn Fungicide 500EC

A solution for certain lawn fungus diseases like dollar spot and powdery mildew.

Efekto Rosecare® Plus

A dynamic three-in-one solution designed to control insect pests, fungus and arachnids specifically on outdoor roses (all types) and garden plants (shrubs, flowering annuals, and perennials).

Efekto Steriseal

To prevent fungus from spreading, use this prune wound paste on roses, grapevines, shrubs and fruit trees after pruning activities.

Efekto Virikop

A combination protective solution made to control fungus and bacteria on listed fruit, vegetables, flowers and garden plants.

Efekto G49 Wetter

A handy solution that increases the wetting and spreading properties of spray solutions. It enhances the activity of various pesticides by spreading and sticking to leaf surfaces, reducing the surface tension of spray droplets.

Will leaf damage disappear?

No, not immediately. Once spots have formed, they cannot be removed. By using these products you will ensure fungal diseases are stopped and new growth is protected. The damaged leaves will eventually fall off and be replaced with new disease-free leaves.

Pro tip:

Wait for the leaves to dry completely to avoid the fungicide from being washed away – Avoid spraying for at least 24 hours after or just before rainfall to ensure the product is effective.

Remember to keep children and pets away from any treated areas until dry.

Dash out plant diseases with the experts

For more help on problems like plant diseases in and around your garden, explore our blog posts or contact our experts.