Identifying the Cause of Crop Damage
Part 2, Section 1: Pest Management
Pest Management
Activities Involved in an IPM Program
Identifying the Cause of Crop Damage
Identifying crop damage is only the first step in pest management. Once damage is recognized, the reason for the damage must be determined. This is a critical step, because an improper diagnosis can be very expensive. For instance, misdiagnosing a boron deficiency as potato leafhopper damage will result in an unnecessary insecticide application plus the final cost of applying boron to the field, along with any lost yield due to the deficiency because it was not corrected at the appropriate time.
The reason for crop damage is not always obvious. Herbicide, disease, and insect damage can look much alike to the untrained observer. Poor plant emergence can be caused by diseases, insects, soil compaction, herbicides, or improper planting depth. Wilting plants can be caused by insects, diseases, or drought stress. In some cases, damage to a crop can occur before any visual symptoms are obvious. This is true, for example, with the potato leafhopper. By the time alfalfa leaves begin to turn yellow, the plant has been stunted and the protein content has been lowered. For this reason, field monitoring by an experienced person is essential for minimizing damage.
For an untrained person, determining the cause of crop injury can be frustrating. Therefore, an untrained person should seek help when faced with such a problem. Expertise can be found at the local Penn State Cooperative Extension office, private consulting firms, a crop management association, or a local ag dealer. Sometimes, a neighbor may be helpful in identifying causes of crop damage. Remember, however, the quality of advice can vary greatly.
If you need assistance, the first place to check is your local extension office. If staff cannot help with the problem, they will know where you can obtain assistance.
