DIATOMS GROUND IMPACT OVER Arcethobium globosum Hawksworth & Wiens subsp. grandicaule OF Pinus pseudostrobus Lindl.

Abstract

The study was carried out in a naturally regeneration stand of Pinus pseudostrobus infested with dwarf mistletoe in the Indigenous Community of Nuevo San Juan Parangaricutiro, Michoacán. The objective was to assess the impact of 2-chloroethylphosphonate (Etephon®) and a diatomaceous earth based commercialproduct,MuérdagoKiller®,forthecontrolofArceuthobiumglobosumssp.grandicaule.Arandomizedblockexperimentaldesignwasusedwith5 treatments and 6 replicates. Significant differences were observed among the treatments after 30 and 45 days of applying the treatments (Pr>F = <.0001). In the control sample, after 30 days, the same degree of infection of 2.08 was found compared to the previous evaluation. In the other treatments the infection scores were 0.42, 0.5, 0.6 and 0.6 for treatments 4, 2, 1 and 3, referring to Etephon® at a dose of 2500 ppm and Muérdago Killer® at a dose of 10, 7.5 and 15% respectively. After 45 days the infection values were 0.0, 0.08, 0.17 and 0.17 for treatments 4, 3, 1 and 2, referring to Etephon® at a dose of 2500 ppm and Muérdago Killer® at 15, 7.5 and 10% respectively. It was concluded that treatments applied to the foliage of P. pseudostrobus provided an equivalent suppression on the aerial portion of Arceuthobium globosum ssp. grandicaule using Muérdago Killer® at a dose of 7.5, 10 and 15% to that of Etephon® at 2,500 ppm, foliar death appeared after 15 days and the abscission of the entire aerial portion after 45. The most effective use of Muérdago Killer® was the 7.5% solution in 200 L of water. None of the treatments caused phytotoxic symptoms to the host plant.