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  • Author or Editor: R. S. Young x
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Abstract

A change in orchard culture caused a significant reduction in activity of pine voles (Microtus pinetorum Le Conte). Cultivations in May, July, and November were not as effective as 2 cultivations plus 2 residual herbicide treatments (July and November). A single cultivation in November caused a small but significant reduction in vole activity but the effect was short lived. A heavy annual residual herbicide treatment in July caused a small but significant reduction in vole activity. No cultural treatment resulted in adequate control by December of 3 consecutive years and toxic hand placed baits were required each year to reduce populations.

Open Access
Authors: and

Triclopyr was applied once or twice in consecutive years to Virginia creeper [Parthenocissus quinquefolia (L.) Planch.] that was growing along the ground beneath the peach [Prunus persica (L.) Batsch.] tree canopy. All rate (0 to 1.1 kg·ha-1) and month combinations controlled Virginia creeper during the season of application. A single application of triclopyr at 1.1 kg·ha-1 was insufficient for control beyond 1 year. Satisfactory control of Virginia creeper was obtained with two applications of triclopyr at 1.1 kg·ha-1 made in either August or September. Chemical name used: [(3,5,6-trichloro-2-pyridinyl)oxy]acetic acid (triclopyr).

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Abstract

Chilling sensitivity of ‘Fuerte’ and ‘Hass’ avocados (Persea americana Mill.) is a function of the stage of the climacteric. The least sensitive stage is postclimacteric where fruit can be kept at 2°C for 6 to 7 weeks. ‘Hass’ avocados on the climacteric rise and at the climacteric peak were most sensitive to chilling and showed injury after 19 days of treatment at 2°. Postclimacteric fruit could be transferred to 2° at 36 to 48 hours after the climacteric peak. The time preclimacteric fruit could be held at 2° varied during the picking season but could be as long as 30 days.

Open Access
Authors: and

Abstract

Pine vole, Microtus pinetorum LeConte, activity in an apple orchard was reduced by cultivation of a 4 m-wide strip down the tree row. Bare-ground-culture using a single annual application of Simazine plus Amitrol (1964-71) or Paraquat (1972-73) herbicide for 10 years reduced pine vole activity.

Open Access
Authors: and

Abstract

Hand placement of 2-Diphenylacetyl-1,3-indandone (Diphacinone, DPN) and [(chloro-4-phenyl)-1-phenyl-1] acetyl-2-dioxo-1-3-indane (Chlorophacinone, CPN) baits applied in 2 applications at ca 30 day intervals at 11.2 kg/ha (10 lbs/A) each were effective in the control of pine voles (Microtus pinetorum LeConte) in apple orchards. In a cultural experiment designed to control pine voles, one Diphacinone preparation gave near 100% control with one application in plots previously cultivated and treated with residual herbicide in July and November.

Open Access
Authors: and

Abstract

Avocado fruit (Persea americana Mill. ‘Fuerte’) were stored in air with or without C2H4 treatment (100 ppm) at 6°, 9°, 12°, 14°, 16°, 20°, 24°, 27°, 30°, and 34°C. During the storage period, respiration was measured by an automated continuous gas flow system. Fruit stored in air for more than 20 days at 6° developed chilling injury as indicated by gray discoloration of the mesocarp tissue. At high temperatures (30°, 34°), avocado fruit ripened abnormally, showed considerable surface pitting, and had poor flavor. When fruit were stored with 100 ppm C2H4, tissue discoloration was severe below 12°, which implied that chilling sensitivity of avocado fruit increased with C2H4 treatment. Fruit, whether stored with C2H4 or not, showed breaking points around the same temperature region on an Arrhenius plot, suggesting possible involvement of other mechanisms in addition to phase changes of membrane lipid components.

Open Access
Authors: and

Abstract

Fruit growth of avocado (Persea americana Mill.) fruit measured by the increase in length, diameter, and volume was initially rapid, but later slowed to a linear growth. Linear extrapolation to zero from growth rate in the descending portion gave a definite point indicating that physiological maturity had occurred. In many cases, this physiological maturity date correlated well with horticultural maturity date determined by taste-panel analysis.

Open Access

Abstract

The Tm-2a gene and probably the Tm-2 gene, both of which confer resistance to tobacco mosaic virus (TMV), were used to develop fresh-market type red tomato (Lycopersicon esculentum Mill.) lines. Crosses were made between lines carrying these genes and susceptible fresh-market type tomato cultivars. Progenies were screened for resistance to TMV by inoculating with 5 known Ohio strains and inheritance was studied at 17° and 28°C. The highest level of resistance to all virus strains was obtained when the 2 resistant genes were combined in a single cross.

Open Access

Apple cuticular wax is the primary environmental interface between the fruit and pathogens or protectant chemicals. Analyses have shown quantitative and qualitative differences in wax of apple cultivars grown in various environments. Of the twelve major wax components, seven exhibited significant variations between Golden Delicious(GD) and Red Delicious(RD) cultivars in all three years. Of these seven components, two compounds occur in greater concentrations in RD than in GD cultivars, one which elutes soon after hexacosanol comprises 10 to 15 % of the RD wax composition verses less than 0.5 % in GD. The other compound comprised 5% of the RD wax verses 1-2% in GD. The other five compounds were found in greater concentrations in GD than RD cultivars. Tetracosanol and another early eluting unknown compound each make up 1 to 3.5 % of GD wax composition while appearing in only trace amounts in RD cultivars. Hexacosanol and a third later eluting unknown each constitute 2 % of GD while concentrations in RD were consistently 1 % or less. Ursolic acid, appears as two isomers, the first isomer constituted 12 to 16 % of GD wax and only 8 to 9 % of RD cultivars. Nonacosane and the major isomer of ursolic add constituted 50 to 70% of the total wax of each cultivar and were not significantly different.

Free access

Mature zygotic embryos dissected from ginseng (Panax ginseng C.A. Meyer) seeds were cultured on Murashige and Skoog (MS) medium containing various concentrations of 2,4-D and kinetin. Somatic embryos were induced directly from cotyledonary tissue and from intervening callus. The frequency of somatic embryo induction was up to 55% of zygotic embryo explants. Upon transfer onto half-strength MS medium supplemented with 1 mg BA/liter and 1 mg GA3/liter, most somatic embryos developed into plantlets. More than 50% of the plantlets flowered after 4 weeks of culture, and some developed immature fruits in vitro. These results indicate that adulthood of ginseng root explants is not a prerequisite for flowering of plantlets regenerated through somatic embryogenesis. Chemical names used: (2,4 -dichlorophenoxy) acetic acid (2,4-D); N-(2-furanylmethyl) -1H-purin-6-amine(kinetin); N-(phenylmethyl) -1H-purin-6-amine (BA); gibberellic acid (GA3).

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