The Diamondback Moth (DBM) control relies almost exclusively on chemical insecticides. In the Federal District (Brazil) it is unknown how growers use those agrochemicals to control the pest. In this work, farmers from two production areas were interviewed and described how they had used insecticides. The results showed that 12 commercial products, belonging to five different chemical groups were used; from this total, five were not registered for brassica usage. Thirty-eight per cent of the farmers sprayed their crops once a week, whereas 21% sprayed twice. This procedure was considered inadequate to control the pest and increases the production cost. Fifty-three per cent of the farmers used only one commercial insecticide which contributes to rapid selection of resistant populations. On the other hand, thirty-four per cent of the growers used two types of commercial insecticides in rotation. In some cases, rotation was carried out with insecticides belonging to different chemical groups, which is recommended; in other cases, different commercial products, with the same active ingredient, were used. This practice is not effective because it doesn't delay the selection of resistant populations. Some growers did not observe the post application waiting period before harvest which means that some crops could have high levels of insecticide residues. In summary it was observed that growers have little information about technical performance of insecticides and little access to research results. Solutions for that problems are discussed.
Plutella xylostella; cabbage; cauliflower; chemical control
