Diagnosis
First, and most important, consult with a reliable resource to accurately diagnose the problem and discuss treatment options before acting. You can telephone or email us for a personal, detailed response. To help us serve you better, please complete this form. To help you self-assess the problem, see the NC Extension Gardener Diagnostic Table.
Is the problem the plant or the site? Consider whether the plant is fundamentally unsuited to the current location and should be moved or replaced. Note that because gardens are continually evolving, shade and tree roots can become issues over time. A plant that once thrived may now struggle.
Control vs. eradication
When assessing a disease, insect or weed problem, consider the long-term consequences of various treatment options. Eradication is not usually a practical goal and can require frequent use and/or high doses of chemicals. Because many garden chemicals are not specific in their effects, they create environmental imbalances that are more destructive than the immediate, but short-term, benefit. Try instead to achieve acceptable control with minimal environmental impact.
Prevention
Focus on prevention first. This is particularly important for diseases, because chemical control is not possible for most bacteria, nematodes, viruses or phytoplasma, and available fungicides usually are effective only for prevention.
| Genetics | Purchase resistant cultivars that are adapted to the growing conditions in your yard. |
|---|---|
| Siting | Avoid situations that encourage disease. For instance, don’t plant species that are sensitive to rust (members of the rose family like apples, quince, hawthorne, serviceberry) near junipers, which are the alternate host. |
| Spacing | Proper spacing eliminates competition for nutrients and permits good air circulation, helping foliage to dry quickly. |
| Variety | Avoid large groupings of the same plant, which create a hospitable environment for pests and diseases. |
| Culture | A healthy plant is more resistant. Improve your soil structure, check the pH, and fertilize as needed. |
| Mulch | Mulch reduces splashing of disease organisms onto foliage and improves plant vigor by conserving soil moisture and moderating soil temperature. |
garden chemicals
Use mechanical and cultural methods as well as chemicals. The wise gardener uses chemicals only as needed, when needed, and where needed.
Label instructions
For the safety of your plant, the environment, and your family and pets, treat only plants specifically listed on the label and only at the recommended concentration and dosing schedule. Too much can be toxic, while too little will be ineffective and can encourage the emergence of resistant organisms.
Granular herbicide
Broadcast application of granular herbicide does not effectively control weeds because little of the product contacts weed foliage. The majority falls to the surface and is eventually carried away in runoff. In addition, granules pose a significant hazard to birds, who often mistake them for food. Spot-application of liquid herbicide directly on the weed delivers the greatest benefit with the least risk and the lowest cost.
Timing
Pests, diseases, and weeds often are sensitive to chemical control only during a specific stage of their life cycle. Chemicals applied at other times have no beneficial effect but still create an environmental burden.
Product persistence
Products whose activity persists for long periods are more likely to pollute groundwater (through leaching) or surface water (through runoff).
Spills
Pick up granules that land on hard surfaces; don’t wash them into the drain.
Further reading
- How to responsibly apply yard chemicals
- NC Agricultural Chemicals Manual
- Earth-wise Guide to Products
toxicity ratings: human, aquatic, birds-bees-pets; soil mobility; persistence - Least Toxic Products by Problem
