Selection of refuges for Nesidiocoris tenuis and Orius laevigatus . Virus reservoir risk assessment

Preliminary results have identified Mentha suaveolens Ehrhard and Dittrichia viscosa (L.) Greuter as promising candidates to be used as refuges for enhancing the activity of predators on protected crops. The first one as a refuge of the flower bug Orius laevigatus and the second as a refuge of the mirid bug Nesidiocoris tenuis, in the southeast of Spain. Augmentative releases of O. laevigatus and N. tenuis are commonly used on protected peppers and tomatoes, respectively, under IPM programs. However, establishment of these natural enemies is sometimes too slow to avoid pest problems in this area. Samplings of the native vegetal species surrounding the greenhouses were conducted to identify the natural host species of these predators. A risk assessment of the identified refuges as possible hosts of pests and viruses that can damage the crops was also completed. Results showed that M. suaveolens and D. viscosa host high populations of O. laevigatus and N. tenuis, respectively. No viruses were detected on both refuges and none were able to be infected, neither by mechanical inoculation nor by whitefly transmission.