The use of pheromone-based or semiochemical lures and devices for the detection
of insect pest population and monitoring in agriculture is a common practice. In many
countries the use of these devices is exempt from registration requirements based
on regulatory thresholds set by the relevant authorities, however, not in South Africa.
The question arises whether the pheromones or semiochemicals dispensed through
such devices, influence the naturally occurring compounds observed and whether a
concern of toxicity and ecotoxicity is justified. A tomato field was selected in a commercial
growing area of South Africa and a novel five-component lure, T.V.
PheroLure®, was identified from a local manufacturer, Insect Science (Pty) Ltd. The
T.V. PheroLure® consists of a Volatile Organic Compound (VOC) blend which is
placed in a polyethylene bulb. Tomato VOCs were collected before, during and after
the application of the T.V. PheroLure® which was used in combination with a yellow
bucket funnel trap. The VOCs were collected at different heights (0 cm, 30 cm and
60 cm) of the tomato plants, from planting until harvest (22 weeks) and surrounding
tomato fields without the T.V. PheroLure®. The results obtained indicated that: (i)
the T.V. PheroLure® had no significant influence on the natural VOCs observed in
the tomato field and (ii) that the height of sampling had no influence on VOCs observed.
This study also indicated that apart from a slight increased contribution of
limonene, there was no significant influence observed from the T.V. PheroLure®
compounds on the natural background VOCs found in the tomato field. Therefore,
it could be argued that the natural phenology of the plant has a greater influence on
the VOCs observed than T.V. PheroLure® and that the concern of toxicity and ecotoxicity is unjustified when using these devices for monitoring purposes only. / Environmental Sciences / M. Sc. (Environmental Science)
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:unisa/oai:uir.unisa.ac.za:10500/27479 |
| Date | 01 1900 |
| Creators | Van Tonder, Aletta Johanna |
| Contributors | Nortje, G. P., Botha, B. M. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | 1 online resource (xi, 56 leaves) : black and white illustrations, color maps, color graphs, color photographs, application/pdf |
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