Prevention is always better.
Harmful insects and diseases usually attack weak unhealthy plants. As soon as you see signs of pests
or diseases check whether the plants are being fed and watered correctly and are growing in suitable
conditions for their needs.
If there are any problems even when conditions seem to be optimal, seek expert advice. Remember pesticides
can be harmful to humans and friendly insects if used incorrectly.
Identifying Common Pests & Diseases
Root and Crown Rot: The problem is most often detected in flowerbeds that have been planted with same
species year after year. The plants that are more vulnerable to this disease are Pansy, Petunia, Snapdragon
The crown base or lower stem of infected plants normally rot at or near soil line, as the disease progress
the entire plant usually turn yellow or wilting followed by complete death of the plants.
Crop rotation is recommended for the management of Phytophthora, but do not alternate planting with
the above plants, e.g. do not pull out Pansy and plant Petunia or Snapdragon, but use plants like
Marigolds, Zinnia, Poppies, Calendula, etc.
Improve soil drainage - the disease is associated with heavy clay soils.
Allow the top 1/2 to 1 inch of soil to dry out before next watering.
It is also important to raise flat planting areas so that the water will drain off rapidly and
not saturates soils.
Black Root: Black Root is the fungal disease that usually starts at root tips and through root
hair. This disease is a problem on pansies during the late summer months when temperatures are high.
The symptoms with seedlings are stunting and a pale green to yellow discoloration of leaves.
Crop rotation is recommended for the management of black root disease. Avoid planting pansies during
late summer hot months.
Snails & Slugs
Causes holes in the leaves of young plants and can chew right through the stems of newly planted seedlings.
Put down snail bait immediately after planting and re-apply until plants are older and well established.
These green-grey caterpillar live in the soil and only appear at night when they eat the stems of young
seedlings at or just under the ground, which causes the seedlings to wilt and fall over.
Sprinkle granular cutworm bait over before planting.
Small sucking insects usually found on new growth. They come in shades of green, red or brown and they
all have fat little pear shaped bodies. They feed by piercing plants and sucking the juice of plant sap
result in leaves being distored, curled and failing to develop. They also secrete a sticky substance
called honeydew that often results in the colonization of an ugly sooty black fungus.
Spray with a suitable insecticide for sucking insects.
Red spider mites
Can be identified as minute red dots on the underside of leaves and is a problem in hot dry conditions.
Leaves turn mottled yellow and fall off prematurely.
Water the undersides of plants and avoid stressed plants due to lack of water and food. Spray with a
The white powdery deposit found on leaves, stems and buds of plants such as poppies, dalia, verbena and zinnias.
Don't water late afternoon or at night. Make sure sun loving plants are planted in full sun and shade loving plants get enough light.
Or spray with a suitable fungicide.
The red or brown powdery substance found on the undersides of the leaves of plants such as snapdragons
calendula and dianthus. Rust takes nutrition from the plant. Bad infestation may result in total lost of leaves and sometims complete death of plants.
Avoid watering late afternoon or at night and spray with a suitable fungicide.
Such as Chafer Beetle are medium sized brown or greyish beetle, which are only active at night, by the day
hide away. They make large holes on the leaves and or petals sometime leaving only main veins. They are strongly
attracted to light and may become a nuisance in the house during early summer evenings.
Pick off by hand where possible or spray with a suitable insecticide for chewing insects.
These are wingless, oval pinkish or greyish blue covered with white waxy powder.
They excrete copious quantity of honeydew over their host plants on which black sooty moulds develop.
They generally avoid sunlight and become abundant on plants with dense foilage or plants growing in the shade.
Hose down with a strong jet of water or spray with suitable insecticide. Ensure the ants are controlled because they may spread infestation. Or spray with suitable fungicide.