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  • Author or Editor: J. P. Sterrett x
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Abstract

Herbicides were introduced into the vascular systems of 20-and 22-year-old Chinese elm (Ulmus parvifolia Jacq.), pin oak (Quercus palustris Muenchh.), and 20-year-old white ash (Fraxinus americana L.) with a syringe-type pressure injector. Concentrations of triclopyr [[(3,5,6,-trichloro-2-pyridinyl)oxy]acetic acid] triethylamine salt ranging from 90 to 360 g/liter were as effective on all species with 2 injection sites per tree as the combination of picloram (4-amino-3,5,6-trichloropicolinic acid) triisopropanolamine salt + 2,4-D [(2,4-dichlorophenoxy) acetic acid) triisopropanolamine salt at dosages ranging from 8 g/liter + 30 g/liter to 32 g/liter + 120 g/liter. Over 80% kill of Chinese elm tops occurred within 2 months after injection, whereas maximum kill of white ash and pin oak did not occur until the following growing season.

Open Access
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Abstract

Paclobutrazol [(2RS,3RS)-1-(4-chlorophenyI)-4,4-dimethyl-2-(1,2,4-triazol-1-yl-)pentan-3-ol)] was injected into bean plants (Phaseolus vulgaris L. ‘Black Valentine’), California privet seedlings (Ligustrium ovalifolium Hassk.), saplings of red maple (Acer rubrum L.), yellow poplar (Liriodendron tulipifera L.), white ash (Fraxinus americana L.), American sycamore (Platanus occidentalis L.), and one-year-old trees of ‘Golden-Delicious’ apple (Malus domestica Borkh), to evaluate growth inhibition response. Also, the extent of translocation and metabolism of injected 14C — paclobutrazol was determined in apple. The height growth, weight, and leaf size of bean plants decreased as the dose of paclobutrazol increased from 0.01 to 1,000 μg/plant. Sprout growth from stumps of privet was reduced as the dose of paclobutrazol increased from 1 μg to 1000 μg/tree. The shoot growth of sapling trees in the field was controlled for at least 2 months with doses of paclobutrazol ranging from 5 mg to 40 mg per tree. When obvious inhibition occurred in apple trees (27 days after injection), 23% of the 14C-activity had been translocated acropetally to the apical shoots. A high percentage of 14C-activity detected was paclobutrazol; 90% of the 14C-activity found in the xylem and phloem and over 85% in the shoot tissue chromatographed with paclobutrazol.

Open Access

Abstract

A pressure injection method was used with abscisic acid (ABA) and 6-benzylamino purine (BA) to control bud break of one-year-old trees of ‘Yellow Delicious’ apple (Malus domestica Borkh). When dormant trees were injected with 3 ml of 250 ppm (wt/vol) ABA, 58% of buds were inhibited after 28 days compared to 31% of the buds of the controls; injections of 3 ml of 200 ppm (wt/vol) BA above the ABA-injection site, induced 52% of the inhibited buds to open. Radioassays of apple stems collected 11 and 9 days after injection, respectively, with 14C-ABA or 14C-BA indicated highly significant increases in radioactivity in the phloem, buds and new shoots compared to radioassays taken immediately after injection.

Open Access

Abstract

Flurprimidol was injected into several species to evaluate effects on growth. Height growth was inhibited 85% in bean (Phaseolus vulgaris L. ‘Black Valentine’) and 90% in California privet (Ligustrium ovalifolium Hassk.) by the lowest flurprimidol doses (125 and 625 μg/plant, respectively). Shoot growth was further suppressed as doses increased. Gibberellic acid reversed the inhibitory effect of flurprimidol on privet. In June, height growth of field-grown yellow-poplar (Liriodendron tulipifera L.) and American sycamore (Platanus occidentalis L.) was uniformly reduced 35% by all flurprimidol doses. By late July, height growth increment decreased linearly as flurprimidol increased from 5 to 40 mg/tree. Thirty-five days after injection of 2.5 mg 14C-labeled flurprimidol in 1-year-old apple (Malus domestica Borkh.), 10% had moved into the new shoots, 1.5% into the scion phloem, and 80% remained near the injection site. A high percentage of the 14C activity was unmetabolized flurprimidol; 95% of the 14C activity in the xylem, 86% in the phloem, and 75% in the shoot. Although it is not highly mobile, flurprimidol effectively inhibits shoot growth, apparently inhibiting gibberellin synthesis. Chemical names used: α-(1-methylethyl)-α-[4-(trifluoro-methoxy)phenyl]-5-pyrimidinemethanol (flurprimidol).

Open Access

Abstract

Low levels of 7-oxabicyclo(2,2,1)heptane-2,3-dicarboxylic acid (endothall), ranging from 37.5 to 300 ppm, combined with 1000 ppm of (2-chloroethyl)phosphonic acid (ethephon) and sprayed on pin oak (Quercus palustris Muenchh.) seedling sprouts in the greenhouse caused temporary defoliation during the initial stages of leaf development. Defoliation was 75 to 86% with a 75 ppm endothall/1000 ppm ethephon combination applied during the first 27 days of leaf expansion. In field trials a 75 ppm/1000 ppm, endothall/ethephon combination defoliated 85% of 17 year-old pin oak trees in the expanding leaf stage. Shoot damage was negligible and foliar density of field trees reached 90% of control 10 weeks after defoliation.

Open Access

Abstract

A miniature pressure injector (mini-injector) was designed specificially to introduce solutions into the vascular system of seedlings and branches of woody plants for research purposes. The mini-injector consists of modified Vise-Grip locking pliers, a stainless steel tapered barrel and disposable syringe. Azo sulfamide dye was successfully injected into 4 species of container-grown fruit trees and 12 species of shade trees. Injections were more consistently effective in June, August, and October than in April. Diffuse-porous species were generally more receptive to injection, especially before bud break, than ring-porous species.

Open Access

Abstract

7-Oxabicyclo (2.2.1) heptane, 2-3-dicarboxylic acid (endothall) alone was not an effective chemical abscissor of bean leaves (Phaseolus vulgaris L. cv. Red Kidney) until a concn of 30 to 40 mg/liter was attained, but in the presence of 800 mg/liter (2-chloroethyl)phosphonic acid (ethephon) abscission began at 5 mg/liter endothall. Low pH (1.5) significantly lowered the break strength of abscission zone explants of leaves sprayed with ethephon and endothall compared to pH 6.0, and endogenous ethylene production from endothall alone was higher at pH 1.5 than pH 6.0.

Open Access

Abstract

Six species of seedling trees were foliar-treated in greenhouse experiments with 7 - ox ab icyclo(2,2,l)heptane-2,3-dicarboxylic acid (endothall) mixed with (2 chloroethyl) phosphonic acid (ethephon). A range of 75 to 100% abscission was obtained within 14 days with little or. no damage except on Chinese elm (Ulmus parvifolia Jacq.).

Open Access

Abstract

To explain the synergistic interaction on abscission between 7-oxabicyclo(2,2,l)heptane-2,3-dicarboxylic acid (endothall) and (2-chloroethyl)phosphonic acid (ethephon), absorption and translocation of foliarly-applied 14C-ethephon alone or together with endothall were determined with (Phaseolus vulgaris L. cv. Red Kidney) plants using liquid scintillation, autoradiography, and gas chromatography. More l4C-ethephon remained in the treated leaf when applied in combination with endothall than when applied alone. These results suggest that the synergistic interaction between endothall and. ethephon can be attributed to transport inhibition thereby increasing the availability of ethylene for the abscission process.

Open Access

Field cage experiments were conducted in Ithaca, N.Y. in 2001 to determine the yield effect of potato leafhopper (Empoasca fabae) infestations on early-stage beans (Phaseolus vulgaris). Yields of `Hystyle' snap beans and `Montcalm' dry kidney beans were significantly reduced when infested by potato leafhopper at the cotyledon, two-leaf, and four-leaf stages. For snap beans, no differences in yield response from potato leafhopper were observed among the three plant growth stages. For dry beans, there was a difference in yield response between cotyledon and four-leaf-stage plants. Dynamic economic injury levels for potato leafhopper on early-stage beans are suggested.

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