Horticoop researches relationship between bark substrate and Lyprauta in orchid cultures
Right from the moment that orchid growers were confronted with the Lyprauta issue, they began to voice their suspicion that the infestation originated in deliveries of bark substrate. So far, however, no Lyprauta larvae have been detected during inspections of uncultured substrate. In practice, Lyprauta has become an increasing problem due to changes in growing conditions, as well as the restrictions on the use of some pest control agents.
Working group
Following recent tests on growers' premises, Horticoop set up a working group – which includes a number of growers – to establish whether the Lyprauta larvae did in fact originate from bark substrate, as had been suggested by the results of the tests. The working group first established a protocol, and on the basis of this protocol, tests were conducted to establish the presence or absence of Lyprauta in bark substrate with reasonable certainty. The second activity was to pinpoint the risk of contamination within the chain. Thirdly, the work party conducted research into methods for the decontamination of bark substrate. A brief explanation of these activities can be found below.
Tests
On the basis of the research protocol, researchers from the University of Wageningen (WUR) and the breeders Anthura conducted research into the presence of Lyprauta in substrates. Three types of sample were inspected: processed raw bark (steamed at source), non-processed raw bark and commercial substrate. Lyprauta larvae were not detected in any of the test samples offered for inspection. To enhance the reliability of the test results, testing will be repeated during a period when the presence of Lyprauta in nurseries is more likely.
Risks of contamination
The working group analysed the bark chain and made an assessment of each link for the risk of Lyprauta contamination. This process clearly mapped out which links in the chain require special attention. This assessment has made it clear that risks are greatest during bark storage at customer premises and during the cultivation process itself.
Decontamination
Anticipating the results of research into the presence of Lyprauta larvae in bark substrate, the working group also conducted a study into the most effective ways of decontaminating bark substrate. Several methods were considered, including UV light, freezing and heating by steaming or radio waves. Currently, steaming at the source would seem to be the best decontamination option. It should be pointed out, however, that decontamination takes place not to eliminate Lyprauta larvae, but also with a view to the possible presence of other pests and diseases. This is all the more important since awareness of fytosanitary aspects has increased in recent years, and Horticoop is intent on the optimal management of its part of the chain as well the elimination of potential risks.
Steps & measures
Based on the results of research conducted so far, Horticoop has defined the following course of action.
1. Checking for the occurrence of Lyprauta larvae in bark will be repeated during a period of the year when the presence of Lyprauta is more likely in nurseries.
2. Monitoring the presence, if any, of Lyprauta larvae in bark will be integrated into the Slingerland Potgrond quality assurance system.
3. Horticoop intends to decontaminate all bark at source, using a steaming method, as from January 1, 2015. The aim of this measure is not to prevent possible contamination with Lyprauta, but primarily to deal with all fytosanitary aspects. It is not likely that this measure will reduce the occurrence of Lyprauta larvae on nursery premises.
4. Consultation with the Lyprauta working group will continue.
5. Horticoop will aim to identify — in collaboration with growers — ways to reduce the problem of Lyprauta in nurseries
For more information:
Horticoop
[email protected]
www.horticoop.nl
