Resumen

CONTRERAS RUIZ, Claudia; ALVARADO ROSALES, Dionicio; CIBRIAN TOVAR, David  y  VALDOVINOS PONCE, Guadalupe. Chemical control with ethephon (2-chloroethylphosphonic acid) of the true mistletoe Struthanthus interruptus (Kunth) G. Don. Agrociencia [online]. 2018, vol.52, n.5, pp.741-755. ISSN 2521-9766.

True mistletoe Struthanthus interruptus affects numerous arboreal species in Mexico City, principally Populus deltoides, one of the most abundant. The infection causes physiological and structural alterations, and in some cases the death of the host, thus the permanence of a considerable number of trees is at risk. In addition to the pruning of branches, one option is chemical control with herbicides injected into the trunk of the host. Ethephon is a growth regulator used in the management of mistletoe with favorable results. The objective of the present study was to evaluate the application of three doses of ethephon (2-chloroethylphosphonic acid) and sterile distilled water (control) injected into the trunk of trees of P. deltoides as a chemical control measure of the true mistletoe S. interruptus. The hypothesis was that the injection of ethephon causes the early detachment of the leaves of mistletoe. The experimental design was completely randomized with seven replications. The treatments with ethephon were low (2 mL), medium (3 mL) and high (4mL) doses, and a control (2 mL) per centimeter of normal diameter of the tree injected into the trunk. The experimental unit was the shrubby clump of the true mistletoe S. interruptus present in a tree of P. deltoides and the total experimental units were 28. The response variable was defoliation of the mistletoe (%) evaluated at 165 d after the applications (April and August). The data were analyzed through an ANOVA with the GLM procedure, and the means were compared with the LSD test (≤ 0.05) using SAS (version 9.5). The ethephon caused the reduction of 31 to 56 % with respect to the initial foliage density. The differences between treatments with ethephon and the control were significant (p ≤ 0.05). The high dose caused greater defoliation among the treatments, (56.29 %), followed by the medium (31.14 %) and low (31.00 %) dose, which were not statistically different. The dynamic of defoliation varied in the time of evaluation; the treatment with sterile distilled water caused a gradual effect during the experiment. The low, medium and high dose with ethephon showed a very similar dynamic, but the highest dose showed its greatest effect on day 28, and the others on day 56.

Palabras llave : true mistletoe; Populus; Struthanthus interruptus.

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