Chapter 21

Integrated Pest Management for Greenhouse Crops

Accurately Identifying Pests

The first step in any pest management program is to accurately identify the pest, whether you are dealing with an insect, weed, plant disease, or vertebrate animal. This step is essential in determining appropriate and effective IPM decisions. Pesticides and other pest management strategies may be effective for one pest may not be appropriate for another. Some pests cause similar damage. In addition, poor plant growth and damage is not always caused by pests; sometimes these problems are due to environmental and cultural conditions that cannot be remedied with pesticides. If problems are incorrectly diagnosed, inappropriate chemical treatments could be used that will be ineffective and add unnecessary pesticide loads to the environment. Once the pest has been accurately identified and confirmed that it is causing damage, become familiar with its life cycle, habitat requirements, time and location of occurrence, and reproductive habits. Pests may leave signs of their presence or symptoms of characteristic damage on hosts and can help in pest identification. Pest symptoms include such things as insect feeding indicators, discoloration from diseases, or reduced plant growth due to competition with weeds for nutrients. Pest signs are parts of the pest itself or other evidence of their presence. The more you know about a pest, the easier and more successful pest management becomes.

Identifying Insects

Identification is critical to distinguish between insect pests and beneficials. Insect identification is based on morphological features such as the structure of mouthparts, wings, legs, antennae, etc. The type of damage observed in the plant and where the pest is located on the plant will also help determine which pests are present. Many pests have chewing mouthparts and eat plant tissue.

Identifying Pathogens

Several types of microorganisms can cause a reduction in plant health including fungi, bacteria, virus, and nematodes. Identification of these organisms in the greenhouse is usually very difficult, and lab identification is often required. Diseases and disorders of plants occur when normal plant function is disrupted. For this reason, pathogens can easily be confused with environmental (non-organism related) stresses. Although symptoms between a disease and an environmental stress are often indistinguishable, they can often be separated by the pattern in which they are distributed within the greenhouse.

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