By growing a plant in an environment that favors its survival, you should be able to avoid most pest and disease problem. Unfortunatly, sometimes our best efforts to give a plant a comfortable place to live are not enought. This page will hopefully help you if you encounter these problems.
Wilts/Root Rots: Can be caused by high rootzone temperatures or waterlogged, low oxygen conditions. Some wilts can be caused by specific pathogens like Pithium, Fusarium, Phytophthora ect. Treatment: Good growing temperature and avoiding excessive watering. Disease resistant varieties. Beneficial microbes. I like to use a mycorrhiza mix. Sterilizing growing pots, trays, tools usually with steam or 10% bleach solution. Chemical fungicides are available.
Leaf/Flower/Fruit Diseases: downy mildew, powdery mildew, black spot, rusts, anthracnose, botrytis. Usually caused and spread by wet foliage and humid conditions. Treatement: Good growing conditions. Keep foliage dry, water in the morning. Disease resistant varieties.
Fungicides:
- Copper Spray – Broad spectrum fungicide
- Neem Oil – has fungicidal and insecticidal properties
- Chlorothalonil – Broad spectrum fungicide
Viruses: Not much can be done if your plant has a virus. If it does have a virus, it is usually best to remove the plant and put it in the garbage or burn it. It can be difficult to tell if your plant has a virus or if there is some other problem. You may see a mosaic pattern on the leaves, leaf curl, stunted growth, necrotic spots. Control: buy healthy plants and disease-free seed, use resistant varieties, control insects that spread the virus.
Pests: caterpillars, scale, aphids, mites, thrips, beetles, white flies, worms, grasshoppers.
Pest control options:
- Hand removal – you can easily get rid of caterpillars by just removing them by hand.
- Spraying with water – giving a plant a vigorous spraying is a great way to remove spider mites and sometimes aphids.
- Bacillus Thuringiensis (BT) – the classic organic option for getting rid of a variety of caterpillars and worms. BT also kills mosquito larvae in standing water like rain barrels. Usually sold as donut shaped “dunks.”
- Horticultural Oil – another organic option that works on soft bodied insects. The mineral oil smothers and suffocates small insects.
- Neem Oil Extract (Azadirachtin) – Derived from the seeds for the neem tree, Azadirachtin is another organic broad spectrum insecticide. Low risk to pollinators, apply at dawn or dusk.
- Cyfluthrin – broad spectrum insecticide. Toxic to pollinators, avoid applying when plants are flowering. Apply at dawn or dusk when pollinators are least active.