Maltol protects against infection of lodgepole pine seedlings by western gall rust

Abstract

Uptake and translocation of maltol into 6-week-old Pinusconforta (Engelm.) var. latifolia seedlings was followed by means of gas chromatography. Maltol concentrations of 6.0–7.3 mg/g seedling dry weight (46–55 μg/seedling) were observed over the first 3 days following a single application of 50 mg maltol/seedling. A split-plot design was used to determine if maltol could reduce seedling infection by Endocronartiumharknessii. Whole plots consisted of two inoculum levels (7 or 30 mg of spores per tray of seedlings) and subplots consisted of four levels of maltol (0, 2, 10, or 40 mg/mL) applied 2 days before inoculation to one-half tray of seedlings at the rate of 5 mL/cavity. The highest concentration consistently and significantly reduced seedling infection relative to the untreated control, although it also caused some phytotoxicity.