CONSTANT PRESENCE OF COMPLEMENTARY PARASITOIDS FOR PREVENTIVE CONTROL OF APHIDS IN ORNAMENTAL PLANTS

Viridaxis is a Belgian company which developed a new, plantless way of mass-rearing aphid parasitoids. Due to its innovative and unique technology, Viridaxis has been able to produce one new selected parasitoid species every year.
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 variety 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 designed.
Here, we show the results of trials made with OrnaProtect in 2010-2011 on several crops (Hydrangea, Cyclamen, Gerbera, Begonia, etc.).
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. Here, we show that it is possible to reinforce this long lasting emergence by mixing mummies of different ages, older mummies (stored at low temperature) emerging earlier after release than young mummies. We describe how the mix was optimized by studying the impact of storage at 7°C on the survival and emergence dynamics of 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.