Colored Sticky Traps for Catching Thrips in Orchid Crops
These thrips are an important quarantine pest. The presence of thrips on cut flowers grown for export can mean that the importing country rejects the shipment, or insists on a disinfestation treatment.
Populations of thrips should be monitored routinely, as the basis for integrated pest control. Thrips are monitored either by visual inspection of a sample of plants, or by the use of sticky traps.
Adaptability of the Technology
In the case of Dendrobium orchids, the optimum sampling size for monitoring thrips is 40 inflorescences (flower heads) for each 1,600 square meters. In general, fields of orchids in Thailand are so large are (1.5 - 30 hectares) that monitoring for thrips by sampling plants is difficult.
Sticky traps are a low-cost technology used by farmers to detect pests in many crops, as the basis for timely and effective pest control (Fig. 2). The farmers can use recycled materials to make the trap cards.
Explanation of the Technology
White and bright blue are the best colors for sticky traps used to capture T. palmi on orchids. Sticky traps hand-made by local people using white PVC board are as effective in trapping thrips as the commercially imported sticky traps (Fig. 3).
The traps should be at a height of 20 - 60 cm above the base of the plants. If they are placed at this height, they will catch more thrips than if they are placed at ground level.
For monitoring purpose, in order to see whether thrips are present, one or two sticky traps should be set out every 220 square meters of orchid plants
(Fig. 4). Research has shown that this will give the number of thrips with a margin of error of 30%. However, for mass trapping, over a large area, sticky traps should be placed at a density of 100 traps per 1,600 square meters.
The economic threshold level at which pesticides should be applied is 10 thrips per 40 inflorescences per 1,600 square meters. If the thrips population is at or above this level, insecticides should be sprayed.
Using sticky trips to monitor populations and tell the farmer when insectides are needed reduces the use of insecticide sprays by 50%, compared to farmers' standard practice of spraying at regular intervals.
Note: This technology has been successfully applied in the production of Dendrobium orchids in Nakhom Pathon Province and around Bangkok in Thailand.
Index of Images
Figure 1 A Dendrobium Orchid
Figure 2 Field of Dendrobium Orchids Shaded by Netting, with White Sticky Traps
Figure 3 Tending Orchids. Note the White Sticky Trap Above the Worker's Head
Figure 4 Orchids in Shade House with Sticky Traps
Download the PDF. of this document, 261,715 bytes (256 KB).
