A sprayable formulation of 1-methylcyclopropene (1-MCP; AgroFresh, Spring House, PA) was applied to ‘Scarletspur Delicious’ and ‘Cameo’ apples in the orchard 1 to 3 weeks before harvest and compared in different postharvest studies with the commercial postharvest 1-MCP fruit treatment (SmartFresh; AgroFresh) and with aminoethoxyvinylglycine (AVG; ReTain; Valent BioSciences, Walnut Creek, CA). Treated apples were held in air storage for 50 to 60 d or in controlled-atmosphere storage for 120 to 125 or 215 to 225 d. With increased concentration, sprayable 1-MCP treatments were effective at controlling flesh firmness loss and internal ethylene concentration (IEC) up to 225 d of storage as well as during a 7-d poststorage shelf life simulation at room temperature. Application closer to harvest improved the effect of sprayable 1-MCP on control of flesh firmness loss and IEC. Concentrations of sprayable 1-MCP above 90 mg a.i./L produced similar fruit effects to 1-MCP. Treatment with 1-MCP showed little effect on soluble solids concentration (SSC), titratable acidity (TA), or skin or flesh color in ‘Delicious’ but slightly increased SSC and TA in ‘Cameo’ apples. AVG applied 4 weeks before commercial harvest controlled IEC nearly as well as either sprayable 1-MCP or 1-MCP during storage, but AVG-treated fruit allowed to ripen for 7 d at room temperature after storage lost much more flesh firmness regardless of storage regime. Sprayable 1-MCP also reduced starch hydrolysis, IEC and fruit drop at harvest. Sprayable 1-MCP may offer new opportunities for effective preharvest management of apple fruit condition, storability, and poststorage fruit quality.

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Plants in the genus Monarda produce complex essential oils that contain antifungal compounds. The objectives of this research were to identify selections of monarda that reduce Rhizoctonia damping-off of tomato, and to determine relationships between essential oil composition of 13 monarda herbages (dried and ground leaves) and disease suppression. Herbages were grouped into five chemotypes, based on essential oil composition and effective concentrations for reducing growth by 50% for Rhizoctonia solani. Replicated and repeated disease control assays were conducted with monarda herbages in greenhouse medium, with or without Rhizoctonia. Percent survival, seedling height, and stem diameter were evaluated at 8 weeks. Survival, seedling height, and stem diameter in herbage-only treatments were not different from the control (no-herbage, no-pathogen) for most herbage treatments. In the pathogen control (no-herbage + Rhizoctonia), seedling survival was 10% that of the control. In pathogen-infested media, seedling survival ranged from 65 to 80% for treatments with thymol chemotypes and 55 to 65% for carvacrol chemotypes. Effective control of Rhizoctonia damping-off was correlated with phenolic monoterpenes; herbages classified as carvacrol chemotypes effectively protected tomato seedlings from Rhizoctonia damping-off disease without phytotoxicity. This study provides evidence that monarda herbages have potential as growing media amendments for control of Rhizoctonia damping-off disease.

Frequency of Douglas-fir bark beetle, Dendroctonus pseudotsugae Hopkins (Coleoptera: Scolytidae), attack on western larch (Lark occidentalis Nutt.) was negatively correlated with 3-carene content of the xylem oleoresin. Concentrations of all oleoresin volatiles from stem cores of standing trees were higher in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) than in western larch with the single exception of 3-carene. Successful brood production by the Douglas-fir bark beetle in standing trees of Douglas-fir but not western larch may therefore be explained, at least in part, by the high 3-carene content of western larch. Other differences between the species that might affect susceptibility to beetle attack include thinner phloem, higher phloem moisture content and larger diameter vertical resin ducts in western larch compared with Douglas-fir. Live standing western larch had no oleoresin exudation pressure, suggesting that this trait is not associated with resistance to attack by the Douglas-fir bark beetle in this species.

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. Paclobutrazol, triapenthenol (RSW0411), and BAS 111 were applied to 4-week-old Delicious apple seedlings (Malus domestica Borkh .) as a root drench at 0 .1, 1 .0, and 10 .0 mg per plant . Paclobutrazol eliminated shoot extension growth for 8 weeks at all three rates . RSW0411 controlled shoot elongation only at the highest rate . BAS 111 produced the widest response, with shoot growth ranging from 38% to 93% of controls for the highest and lowest rates, respectively . Generally, leaf area decreased and leaf density increased with increasing rates of all chemicals . Root weight of plants treated with paclobutrazol nearly doubled but increased only slightly with RSW0411 and BAS 111 . Chemical analysis of the leaf tissue 8 weeks after treatment showed paclobutrazol levels highest, followed by RSW0411 and BAS 111 .

Abstract. Seasonal levels of indole-3-acetic acid (IAA) present in buds, meristematic tissues, and leaves of 1-year-old shoots of two selections (vigorous and dwarf) of a F2 generation apple population with original "Goldspur" × "Redspur" parentage were determined using gas chromatography-selected ion monitoring-mass spectrometry (GC-SIM-MS) with a 13C-IAA internal standard. A comparison of IAA levels through one growing season was made in the shoots of two trees differing in growth. The levels of IAA in the leaves of the vigorous tree were higher in the early and late growing seasons, as compared to those in the dwarf tree. Levels of IAA in buds of the dwarf tree shoots were found to be higher than in those of the vigorous tree shoots.Over the past 30 years there has been a dramatic increase in the planting of dwarfed apple trees. Tree size is controlled by grafting genetically vigorous cultivars onto size-controlling clonal rootstocks. Recently, interest has been expressed in the production of genetically reduced-sized apple trees by breeding dwarf cultivars (Faust and Zagaja 1984). The mechanism responsible for dwarfing of these trees is not yet understood. The existing knowledge concerning the role of auxins (IAA) in the dwarfing of the grafted apple tree has been summarized by Lockard and Schneider (1981). Some studies of growth Substances in genetically dwarfed trees have been done, including the measurement of auxin-like substances for two growing seasons by the Avena curVature bioassay in shoots and vascular tissues of apple hybrids having different

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