Two experiments were carried out to evaluate the impact of sprinkler irrigation on Diamondback moth injuries on cabbage plants (cv. Kenzan). The first experiment, composed by two trials, was carried out at Embrapa Hortaliças. In the first trial, larvae of third and forth stages were transferred to 16 plants with open leaves, 40 days after sowing and on 16 'Kenzan' plants beginning to form head. After 24 hours, pots with cabbage plants were transferred to the field, where half of them were irrigated using sprinkler irrigation system for 30 minutes per day, receiving depth of water of 23 mm. The other half of the pots were the control treatment. On the second trial, carried out at the same way, larvae of the first and second stage were transferred to 40 cabbage plants. The second experiment was carried out at Fazenda Água Limpa, University of Brasília. The experimental design was completely randomized with three treatments (clorfluazuron weekly applied - 400 ml/ha; clorfluazuron applied at crop economic threshold and control, without clorfluazuron) in 10 replicates, total of 30 plots with 24 plants each. It was applied 400 mm of water during crop cycle. The weekly clorfluazuron applications and the weekly crop economic threshold evaluation began 36 days after transplanting. Grades were attributed to eight plants per plot during harvest according to the degree of injuries observed: 01= no damage; 02= few damages; 03= leaves with many injuries; 04= plant totally damaged. Sprinkler irrigation has influence on Diamondback moth control by removing 52% of the larvae when first and second stage larvae were used. No statistically significant difference was observed between the grades of the plants that received clorfluazuron weekly and the plants that received it at crop economic threshold and between the latter treatment and the control.
Plutella xylostella; irrigation; integrated pest management
