IPM strives to minimize problems with insects, mites, weeds and diseases by assessing and focusing on the needs of plants and their proper maintenance. Insuring plants have adequate nutrients and a suitable growing environment above and below ground are the first steps in growing healthy plants. Healthy plants are naturally equipped with healthy immune systems that enable them to ward off disease and attack by pests. More and more studies are published each year showing the relationship between plant health and immune response. In the long term, the best method of managing landscape problems is in creating a landscape ecology that promotes healthy plants.
However, everyone does not have a perfect ecology with perfectly healthy soil and plants. Weather and other disturbances from outside our boundaries can negatively impact our home landscapes. Everyone can benefit from following the guidelines of Integrated Pest Management.
IPM is a four-step system of managing landscape problems by using the methods that are the least harmful to the environment. Through observation of the landscape, recognizing and assessing any problem, monitoring its effects and evaluating the amount of damage, you are able to more effectively manage the problem with minimal environmental harm. The fourth step, management of the problem, emphasizes using the least harmful management method before moving to the next level. The four management techniques or strategies are cultural, mechanical or physical, biological and chemical.
Insect pests first feast on unhealthy plants. The best management tool is to have healthy plants. Prevention of stress on plants is your first line of defense in preventing pathogen infection and pest infestation. Pathogens can be difficult to manage and damaging to the plant once present. Weed infestations are best caught early and managed by proper cultural practices.
Healthy plants are:
- More resistant to attack by insects and diseases.
- More likely to recover from environmental and other stresses.
- Better able to withstand injury.
Plant stress is a main contributor to plant disease, whether caused by a pathogen (infectious), or the environment. There are many stressors to plants, quite a few of them are caused by improper cultural practices, that is, bad gardening practices. Other problems are inherited with the purchase of the property or beyond any one gardener's control, drifting in from outside our landscape boundaries. These are some of the common stresses plants contend with:
- Air Pollution
- Chemical Injury -- Abuse and overuse of chemicals either directly or indirectly through drift, use of persistent synthetic chemicals (pyralids), chemical spills, application by gardeners, good intentions, pet dodo for example
- Soil Drainage Problems -- Imbalance in the movement of air and water through the soil, tight clay or caliche soils, loose sandy soil, hardpan
- Improper Plant Selection -- Inappropriate plant selection for landscape location, soil and climate conditions
- Improper Planting -- Planting too deep, too shallow, or wrong time of year
- Improper cultural practices -- this can include any improper maintenance practices or lack of maintenance, for example, improper pruning techniques
- Insects and Mites -- unbalanced and over populations of pests in the absence of normal biological controls (pest predators), weak immune system of plant
- Light Problems-- Not enough or too much sunlight. A maturing landscape or change in nearby structures can lead to light problems
- Moisture Extremes--Drought, violent downpours, hurricanes, flooding, hail damage
- Wind Extremes -- Excessive wind will stunt plant growth, air born particles will damage or kill plants, desiccation caused by wind
- Nutrient Deficiency and Imbalance -- Over fertilization, unamended poor and depleted soil, for some plants, too much soil amending, soil chemical imbalances
- Pesticide Toxicity -- Abuse and overuse of pesticides
- Root Injury -- Digging in close proximity that severs roots (injury caused by installing irrigation in existing landscapes, for example), machinery compaction of soil
- Salt Applications Nearby -- De-icing, salt buildup from fertilizers and irrigation water with a saline content over time
- Soil Compaction -- from machines, repeated walking, walking on wet soil
- Soil pH Extremes -- Planting plants that require an acidic soil in alkaline soil, and vice versa
- Temperature Extremes -- Such as frost, late spring and early autumn freezes, consistent above average heat, sudden temperature shifts
- Trunk Injury -- Leaving ropes, etc, tied to trunks and branches as they grow without adjusting for growth, girdling and scarring by weed trimmers, sun scald, improper pruning, other mechanical and accidental damage
Conditions for Disease
There are three factors necessary for the appearance of an infectious plant disease: a virulent pathogen, a susceptible host and an environment conducive to development of the pathogen. Disturbing any of these conditions decreases the likelihood of the infection occurring. To correct the problem, IPM depends on correctly identifying all the contributing components.
It's important to determine whether plant disease is caused by an environmental factors or is an infectious plant disease. A number of factors could be the cause of the disease. A plant could suffer from both environmental, improper horticultural practices, and infections plant causes. Favorably changing the environment or removing infectious causes will improve the plant's condition if caught in time.