How to diagnose flower and plant pest damage? Practical methods to help you judge accurately

Methods for diagnosing flower and plant pests can be divided into two categories: first, the direct diagnosis method, which identifies pests by their morphological characteristics at each stage; this method is relatively intuitive and simple; second, the indirect diagnosis method, which diagnoses by pest residues or the damage characteristics of the flowers and plants.

Pest residues include pest derivatives (such as egg shells, pupal cases, molted skins, residual body hairs, and dead pest carcasses) and pest excreta (such as feces, honeydew substances, silk webs, and foamy substances).

When diagnosing damage symptoms on the aboveground parts of plants, be sure to distinguish between diseases and pest damage. In particular, when the roots of flower and plant plants are damaged by pests, the aboveground leaves also show symptoms of yellowing or wilt resembling those caused by nematodes and viruses. At this time, be sure to take the plant roots and observe whether there are insect bite wounds and pest bodies present. For round lesions on plant leaves, also pay attention to whether they may be caused by pest damage. A simple method is to hold the damaged leaf toward sunlight and look through the damaged spot; if the tissue in the spot area is transparent and has no leaf mesophyll, it is very likely caused by pests. This does not rule out the possibility that pest damage occurred first, providing a wound for subsequent pathogen invasion, which is the so-called compound infection.