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Several field trials were conducted to determi­neaction the threshold for the greenhouse whitefly, Trlaleurodes vaporariorum (Westwood), a key pest of snap beans in the Sumapaz Province of Colombia. In two initial trials, chemical control of the whitefly was exerted at different levels of attack defined by means of a visual scale based on the phenology of the insect and damage symptoms. Differential attack levels thus obtained resulted in differential yield responses. The regression of attack levels on yield was: y = 26.7 - 1.43x (r = -0.956**). Economic analysis of the data indicated that the action threshold for whitefly control occurred at the level of attack 3, that is when first instar nymphs appear on the lower third of the plant. In two additional trials, control at level 3 was compared with control at level 5 (honeydew formation) in combination with different fungicidal regimes for disease control. Results confirmed that whitefly control at level 3 could be recommended within the integrated Pest Management scheme proposed for snap beans in the Sumapaz Province.

CARDONA, C., RODRÍGUEZ, A., & PRADA, P. C. (1993). ACTION THRESHOLD FOR THE CONTROL OF THE WHITE FLY OF THE GREENHOUSES, Trialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae), IN GREEN BEANS. Revista Colombiana De Entomología, 19(1), 27–32. https://doi.org/10.25100/socolen.v19i1.10050