Resumen

MALTOS-BUENDIA, Jorge et al. Impact of malathion applications on beneficial insects and effects on Bemisia tabaci in cotton. Ecosistemas y recur. agropecuarios [online]. 2025, vol.12, n.3, e4576.  Epub 05-Dic-2025. ISSN 2007-901X.  https://doi.org/10.19136/era.a12n3.4576.

Applications of the ULV insecticide malathion to control the boll weevil Anthonomus grandis Boheman, eliminate some of the natural enemies, causing the resurgence of the whitefly Bemisia tabaci (Gennadius). This study evaluated the impact of malathion applications on the population density of natural enemies and the effects on the population of B. tabaci, in regions with different numbers of malathion applications. Sampling of natural enemies and whitefly was carried out by sweeps and leaf inspection, with a biweekly frequency, in cotton fields in Tamaulipas (30 applications), Durango (8 applications), Coahuila (2 applications) and Chihuahua (0 applications). Chihuahua had the highest abundance of natural enemies with 35 insects per 100 sweeps, followed by Coahuila with 24, Tamaulipas with 22 and Durango with 21. The highest density of whitefly was observed in Tamaulipas with an average of 4.3 adults and 0.9 nymphs/leaf, Durango with 4.1 adults and 0.5 nymphs/leaf, Coahuila with 1.6 adults and 0.1 nymphs/leaf; while Chihuahua had the lowest density with 0.2 adults and 0.1 nymphs/leaf. These results indicate that in the regions where the highest number of applications of ULV malathion are made, the diversity and population density of natural enemies was reduced by 50% and 37%, respectively, and the density of whitefly is increased (95%), which may be due to the lack of regulatory effect that natural enemies have on this pest.

Palabras llave : Whitefly; natural enemies; insecticide; pest; population density.

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