Plant Health Care

Components of Plant Health Care

Some horticulturists feel IPM does not go far enough. IPM emphasizes pest management, while our concern is with healthy plants that are vigorous and attractive. The difference may seem minor, but it makes a big difference in the way we approach landscape plant management. If we focus on pests, we overlook many basic cultural problems afflicting plants. At the Washington State Univesity Puyallup Plant Diagnostic Laboratory, for example, half of the sick plants submitted for diagnosis are not suffering from insect pests or disease organisms. Instead, their problems result from cultural and environmental factors such as overwatering, drought stress, or winter damage.

In an attempt to develop a more holistic system that focuses on healthy landscapes, several terms have been suggested--integrated plant management, integrated landscape management, sustainable landscaping. One term that has received widespread acceptance in the tree care industry is plant health care (PHC).

PHC is as much a change in attitude as a change in technique. Not only does it emphasize plant health over pest management, it takes an ecosystem approach that emphasizes working with nature instead of fighting nature; it sees proper culture as the foundation of a healthy landscape. PHC is not a rejection of IPM. Basically, PHC has evolved from IPM, still incorporates all IPM principles, but goes beyond IPM.

The first step in implementing a PHC system is to identify and list all plants in your yard. How can you take care of your plants if you don't know what they are? Once you have a plant list, do some research to learn more about your plants: their cultural needs, likely pest problems, common environmental problems. During this research, you will uncover some key plants--those that are problem-prone and likely to require the most attention.

After identifying the plants in your garden, you can determine the key problems, both biotic (living organisms such as insects, fungi, slugs, and deer) and abiotic (non-living factors such as weather, fertility, irrigation). Key problems are the ones most likely to impact plant health and require your attention. For example, rhododendrons are often diagnosed as suffering from root weevils or poorly drained soil. Learn more about these key problems if you grow rhododendrons. For pests, learn to identify various stages of the life cycle, recognize symptoms of damage, and know which management options are both effective and environmentally sound.

The next step is to study your landscape ecosystem. Your garden truly is an ecosystem with complex interrelationships among flora, fauna, soil, weather, and other factors. Be aware of climatic factors, such as minimum temperatures, the amount of sun received by various parts of your garden, prevailing winds, and seasonal patterns of precipitation. Understand soils and drainage patterns. This information is essential, because healthy gardens result from carefully matching plants to the habitats in your yard.

Landscapes are dynamic. Monitor them constantly to keep up with both seasonal and longterm changes. A key to any PHC program is frequent monitoring, at least every two weeks during the growing season and perhaps once a month during the winter. When monitoring, pay particular attention to signs of plant stress (yellow or wilted leaves, dead twigs, etc.), and be on the lookout for developing pest problems. Concentrate your monitoring on key plants and key problems.

With knowledge of your plants, potential problems, and the landscape ecosystem, you have the tools to optimize plant health. A healthy landscape starts with smart planning. Select pest resistant plant species, match plants to the existing climatic and soil conditions ("right plant, right place"), and include a diversity of plant species to limit infestations. Then employ good cultural practices: Improve soil conditions by using organic matter and mulches, practice correct planting methods, and pay careful attention to watering, fertilizing, and pruning (too much of the last three may be just as bad as too little). Sound cultural practices are the basis of a PHC program. They benefit any landscape, whether new or well-established.

If we promote total plant health, we avoid many problems (preventative medicine). Cultural and environmental problems are minimized, and healthy plants are better able to withstand insect or disease damage.

When monitoring indicates that pests require attention, PHC employs an IPM approach to manage them.

Note: Pesticide applications or alternative strategies based on calendar dates are seldom used in PHC or IPM since they are often ineffective. The development of many disease and insect pests is closely linked to plant phenology--for example, the timing of budbreak or bloom. Since these events can occur at different times each year, pesticides and many of the possible alternatives must be applied to correspond to critical periods in the plant's development if they are to work. Properly timed applications maximize their effectiveness and reduce their potential impact on the environment.

 

Next

Back

&