Pests and Diseases
© Copyright Frikkie Marais. Used with permission.
APHID
Small delicate pear-shaped insects with soft bodies and long legs and antennae. Usually greenish or black, with or without transparent wings. Found in small colonies sucking sap of tender growths or flower buds. Often attended by ants. Transmitters of viral diseases.
Treatment:
Chlorpyrifos (Chlorpirifos, Dursban) as a full cover application when necessary.
Mercaptothion (Malathion, Malasol) as a full cover application when necessary.
LILY BORER
Black caterpillar with yellow bands. Feeds on leaves and tunnels into leaves, stalks and bulbs of various lilies and amaryllids.
Treatment:
Cypermethrin (Garden Ripcord) as a full cover application when pest is noticed.
Deltamethrin (Decis) as a full cover application when pest is noticed.
MEALY BUG
Small 3mm long oval-shaped light-pink bodied stationary insect covered by waxy threads with 2 long threads protruding. Found on tender growth. Heavy excretion of honeydew can cause growth of mould. Often attended by ants. Transmitters of viral diseases.
Treatment:
Chlorpirifos (Chlorpirifos, Dursban) as a full cover application when necessary.
Mercaptothion (Malathion, Malasol) as a full cover application when necessary.
Pyrethrin/Fatty acids (natural insecticide) as a full cover application when necessary.
RED SPIDER MITE
Minute reddish-brown “spiders” with four pairs of legs of equal length and oval body. Weave a web on the underside of leaves. Eggs creamy white. Cause yellowing and bronzing of the leaves.
Treatment:
Chlorphenapyr (spidermitespray) as a full cover-application.
Chlorpirifos (Chlorpirifos, Dursban) as a full cover application when necessary.
Tetradifon (Red spidercide) as a full cover application when pest is noticed. Kills eggs and sterilises females
SLUGS AND SNAILS
Greyish-brown slimy legless soft-bodied creature. With (snail) or without (slug) coiled shell. Leaves a shiny trail of viscid secretion. Feed on young succulent growth of a great variety of plants. Active only under damp conditions.
Treatment:
Metaldehyde Karbaryl (Snailbait) scatter bait around.
Methiocarb (Mesurol) scatter bait around.
Carbaryl/Metaldehyde (Snailflo) apply evenly as a drench over plants and pots
THRIPS
Minute insects with four long narrow fringed wings. Immature stages yellowish. Adults dark and very active, having the habit of turning up the abdomen. In order to feed they rasp the plant surface causing small silver blotches. Transmitters of viral diseases.
Treatment:
Mercaptothion (Malathion, Malasol) as a full cover application when necessary.
Gamma BHC (Bexadust) as a dustable powder over plants and affected areas.
WHITEFLY
Small four-winged insects. Wings and body covered by fine white powder. Larvae minute oval-shaped and covered with short white waxy filaments. Suck sap from underside of leaves.
Treatment:
Pyriproxyfen (Whitefly insecticide) apply as indicated
Cypermethrin (Garden Ripcord) as a full cover application when pest is noticed.
Deltamethrin (Decis) as a full cover application when pest is noticed.
SNOUT BEETLE
Brownish-black weevils, with the head elongated into a distinct snout. Feed mainly at night and damage leaves and bracts. Especially problematic in the Cape.
Treatment:
Mercaptothion (Malathion, Malasol) as a full cover application when necessary.
FUNGAL AND BACTERIAL DISEASES
Various pathogenic organisms externally present on the seed, plants or in the soil. They are the causes of diseases like seed rot, root rot, damping-off, rust, leaf spots and bacterial rot.
Treatment:
Copper oxychloride (Virikop) apply as a drench to soils 1.5l per square metre (for bacteria and fungus)
Furalaxyl (Fongarid) apply as a drench to seedlings and cuttings in pots or beds. (for fungus)
Zineb (Zineb) apply as directed. Controls various leaf spots. (for fungus)
VIRUS
Viruses are microscopic organisms consisting of pieces of nucleoprotein, which have to multiply in living tissue. Virus particles can be transmitted by seed, infected gardening equipment, soil and various insects
Treatment:
No treatment available
Suspected plants/propagating material should be destroyed.