Scouting Methods & Options:
There are essentially three options available when scouting your greenhouse crops for insect/mite pests. 1- No scouting performed with pesticides being applied on a calendar timetable. 2- Simply scouting for pest existence with pesticides applied when presence is observed. 3- Scouting crop and making pesticide application decisions based on pest counts and action thresholds. The third option is part of an integrated pest management (IPM) approach that has been promoted throughout the green industry the past few decades.
Greenhouse pest populations are measured by trapping or direct plant inspection, and both involve determining pest numbers. Counting pests and using action thresholds requires time and knowledge, but results in less pesticide use, reduced potential for insect resistance, and can improve plant quality. It is important to remember that trapping (e.g., yellow, or blue sticky cards) improves the efficiency when scouting your greenhouse but does not replace the actual inspection of individual crop plants (Fig. 1 & Fig. 2). This is particularly the case when scouting for aphids and mites.
Fig.1. Yellow or blue colored sticky traps are used to capture flying insect pests in the greenhouse. The blue traps attract the western flower thrips more effectively. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)
Fig. 2. The optivisor (3x) at top of photo works best when counting or viewing the insects captured on sticky traps. The other magnifiers shown (5x, 16x, 20x) are used to more closely view pests on crop plants. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)
