Preventive control of aphids in ornamental plants with complementary parasitoids.

Biological control of aphids can be achieved with parasitoids. A parasitoid is a wasp able to parasitize aphids in a host-specific way. These natural enemies of aphids are used in organic or integrated pest management strategies. In order to apply the matching parasitoid against a given aphid species, the aphid has to be detected in the crop and subsequently identified. By the time the aphids are spotted by the grower and then identified by himself or a specialist, it is usually more difficult to gain control over an increasing aphid population. Viridaxis developed a new concept of aphid control, based not on the species identified but on the crop treated. There was a need for a product controlling the largest possible spectrum of aphid species susceptibly present in ornamental crops. As the first step of development, an inventory of the aphid species attacking ornamental crops was made in various regions. A unique cocktail of parasitoids species (OrnaProtect) controlling all these aphids was then developed. OrnaProtect contains six different species of natural aphid enemies, and is able to control all commonly appearing aphids attacking ornamental crops. The fact of mixing different species not only covers the entire spectrum of aphids, but also contributes to prolonged hatching. To reinforce this long lasting emergence, mummies of different ages are mixed, older mummies (stored at low temperature) emerging earlier after release than young mummies. With that prolonged hatching dynamics, a release every two weeks assures a permanent presence of fresh adult parasitoids in the crop. The ready-to-use units of OrnaProtect contain an integrated feeding point which contributes to longevity and efficiency of the parasitoids. Its application in the crop is much faster than even any chemical treatment. Here, we show the results of trials made with OrnaProtect in 2011 on several crops (Hydrangea macrophylla, Solanum jasminoides, Argyranthemum frutescens and Osteospermum ecklonis). OrnaProtect controlled the aphids in all trials. In one trial, aphids were already present at the time of first release and a localized treatment on about ten plants, compatible with beneficial insects, was applied. After that, an excellent control of the aphids was achieved by the parasitoids. In the other trials, when used in a really preventive way (no aphid at the time of first release, the aphid population was immediately controlled and all plants could be sold as first quality plant without any insecticide treatment.

CerBeruS: a system supporting the sequential screening process

This paper describes the general design and application of CerBeruS, a computer-based system for supporting the process of sequential screening. CerBeruS stands for cluster-based selection, with cluster analysis forming the pivotal part of the system. CerBeruS uses the Ward's clustering method for partitioning the data set to be screened into smaller, more homogeneous subsets. One representative is picked from each subset and suggested as a screening candidate. Although the number of compounds submitted to screening is most often driven by the capacity of the assay, CerBeruS provides a statistical measure that computes the optimal number of clusters in the data set. This measure forms a point of reference for all screening experiments. Different hierarchies of subsets are stored in an Oracle database. Information about the size and content of a cluster can be retrieved from this database via a Visual Basic application. How these components work together in the CerBeruS system is demonstrated on a large data set. In addition, we show that, using the statistical measure, one can find an optimal trade-off between screening effort and number of hits.