Plants & Flowers – Common Pests, Diseases and Problems

Whether you grow your own plants, or purchase fresh flowers for your home, there are a few common defects and diseases that you should be watching for.

aphidsAphids: These pesky little bugs are familiar to most gardeners. They are usually the same green as  the plants they feed on, but are sometimes orange, yellow or even black. Aphids will excrete any excess nutrients and sugars, then ants will collect this extract. It is said if you can get rid of the ants, you will probably solve your aphid problem. There are chemicals available, but a soapy mixture seems to work well without harming the environment. Just make sure you spray the soil around the plant, as aphids will jump off when you are spraying (in an effort to save themselves) and will climb back up on the plant later when your back is turned!

Leaf-miner: An insect, which lays eggs in the foliage and when hatched, the larvae travels through and feeds inside the leaves, leaving a discoloured track. Upon maturity, the pupae falls to the ground and hatches into adult flies and begins another life cycle.

caterpillarsCaterpillars: There a few different types of caterpillars that like to eat leaves, stems, the growing tips and other parts of our plants. To get rid of these find yourself a pesticide that contains B. thuringensis toxin. The B.t. toxin is not harmful to humans, only caterpillars and it is very effective. Usually only one application is needed, but if you have a serious infestation try a repeat application one week after the first. Just read the labels at your local garden center to find one with B. thuringensis toxin.

Botrytis: This is a non-specific air-borne fungal disease that can affect all flower, fruit and vegetable tissues. It loves cool temperatures (<15 C) and must have water to germinate its spores. It shows as raised pin-point spots initially. Botrytis develops into blotches of tan-coloured spots and finally will show as hairy mould if allowed to develop unchecked. Botrytis fungus is a saprophyte and also a parasite. When saprophytic, it feeds on dead decaying tissue; when parasitic, it feeds on living tissue. To avoid this problem, keep your flowers dry. If flowers show the initial signs of Botrytis on the outer petals, peel off those petals to prevent the disease from growing and spreading.

Rust: An airborne fungus that induces blisters containing brown powdery spores on epidermis of stems and foilage.

Fusarium: A root rotting soil borne fungus that lives in the soil and kills carnation plants. There are eight strains of Fusarium.

Heterosporium: An airborne fungus that causes brown spots on the calyx, stems or leaves.

Ethylene Gas: This effects cut flowers in the home. Ethylene is a colourless, odourless gas formed during the normal maturation process of developing fruit, flowers and vegetables. It can be deadly even in minute quantities for short periods of time. Ethylene damage shows as sleepiness in the blooms, that is, the petals tend to curl inward and the flowers feel soft. Avoid Ethylene contaminated situations because once the flowers have breather the Ehtylene gas, there is no way to revive them. Ethylene gas is released by fruits, flowers, vegetables, some woods and cigarette smoke. It is the worst killer of carnations. Keep your vases of fresh flowers away from these “releaser’s” to extend their life in the vase.

Cut flower problems

Discoloration: Caused by cold weather. Results in red carnations and roses turning blue; white getting blue flecks, and reds getting white flecks. Age can also cause fading of colour.

Blown Head: A bloom which is excessively open.

Bull Head: A bloom which has a misshapen head.

Pinking: Pink coloration of flowers in the center of blossom and/or on the outer petals – is the effect of cold weather. An extreme example is a brown center in bloom.

Shattering: Caused by rot at the point where the flower petals attaches to the coccyx. Petals fall out on touch. Also caused by shock.

Single: A bloom with an excessively low petal count. Roses need a certain number of petals to open.

Slab Side: A lopsided blossom. Caused if cut too soon.

Sleepy Appearance: Edges of petals curling in and petals discoloured – caused by ethylene gas or cold weather.

Yellow Foliage: Can be caused by heat, deficiency of nutrients in the soil, or age.


About Connor Lowry

I love flowers! I enjoy writing about them as well as gardening. Mostly I love finding new and unique flower gardening ideas I encourage you to post regularly on this blog, and send in guest blogs or ideas for new blogs as well. New and exciting blogs are always welcome I intend to post a lot of interesting facts and fun stuff about flowers, as well as info on many varieties of flowers.
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