Diamondback moth, Plutella xylostella (L.) causes enormous damage to all important cruciferous vegetables, including cabbage, cauliflower, broccoli, radish, mustard, kale, and others. The pest's damage is especially serious in the tropics where host plants and ideal temperatures for insect development and multiplication exist throughout the year.

Diamondback moth (DBM) is native to Europe. In Europe, DBM causes little damage and control measures are rarely required. This is because about 40 "natural enemy" species attack DBM larvae and pupae, thereby keeping the pest population well below the level where it can cause damage. In the tropics, none of these parasites occur naturally. As a result, DBM populations multiply fast, forcing farmers to use insecticides, the quickest way to check the pest population.

Now, as a result of frequent application, DBM has developed resistance to practically all insecticides, including some strains of Bacillus thuringiensis and other biological insecticides. Moreover, the extensive use of insecticides has increased the cost of production, destroyed biodiversity, placed the health of farmers and consumers at greater risk, and contaminated soil and water.

It is logical that the biological forces that keep this pest under control in Europe be employed elsewhere. This requires the importation and introduction of European parasites into areas where they do not exist.

Indeed, introduction of one such European parasite, Diadegma semiclausum (Hellen), has reduced to a tolerable level the DBM damage in Australia and New Zealand, as well as in the highlands of Indonesia, Laos, Malaysia, Philippines, Taiwan, and Vietnam. In these areas, the use of insecticides in combating crucifer pests has dropped significantly and new marketing opportunities for farmers have emerged.

At the Asian Vegetable Research and Development Center, we emphasize the importance of biological control as part of integrated pest management (IPM) strategies to combat DBM. For the past dozen years we have been importing, rearing, and introducting these parasites in interested countries where they do not exist. We have encouraged national program scientists and other researchers to do the same. To this end, we have trained scientists in developing countries to rear and multiply these beneficial parasites.

This tutorial will explain protocols for mass rearing of five parasites: Diadegma semiclausum, Cotesia plutellae (Kurdjumov), Microplitis plutellae (Muesebeck), Oomyzus sokolowskii (Kurdjumov), and Diadromus collaris (Gravenhorst), so that interested individuals can rear and use these beneficial insects. All of the parasites are available at AVRDC free of cost to interested scientists willing to satisfy the quarantine requirements of the importing countries.

We thank the Swiss Agency for Development and Cooperation (SDC) for their generous support through SDC's Mekong Regional Project to the Asian Regional Center-AVRDC, which made the production of this tutorial possible.