Search Results
Abstract
Three-year-old peach trees [Prunus persica (L) Batsch. cv. Elberta] growing on old peach land where a high incidence of bacterial canker was suspected in previous plantings, were pruned or pruned and inoculated with Pseudomonas syringae van Hall in October, December, February, or April. All trees pruned and inoculated in October or December were either dead or dying by May. P. syringae was recovered from all of the October-inoculated and from 86% and 71% of the December- and February-inoculated trees, respectively. Also, 43% mortality occurred in February-pruned and inoculated trees. Uninoculated but early-pruned trees showed severe short life or decline symptoms with 43% mortality following October and December pruning. On the other hand, April-pruned trees, whether inoculated or not, showed less short life or decline symptoms than early-pruned trees and no deaths occurred in April-pruned and inoculated trees.
Abstract
The ultrastructure of floral abscission zone cells of Phaseolus vulgaris L. cv. Dark Red Kidney was studied in order to relate changes in fine structure to known changes in morphology and physiology of the foliar abscission zone of Phaseolus and to the fine structure of floral abscission zones of other plants. Major structural changes in cell walls are similar in abscission zones of senescing leaves and post-anthesis flowers but the rapidity of cellular changes is greatly accelerated in the latter. Inclusions typically found in floral abscission zone cells of Solanaceous plants are not present in Phaseolus floral abscission zone cells. Cellular changes are evaluated in terms of their potential relationship to the abscission process.
Abstract
Oryzalin, simazine, and metolachlor alone and in combination were evaluated for weed control in field-grown Korean boxwood (Buxus microphylla Siebold & Zucc. ‘Koreana’) and Photinia (Photinia × fraseri) at Belle Mina, Ala., over a 3-year production period. Treatments were applied twice during each growing season. Greatest control of the annual grass and broadleaf weed species was with oryzalin tank-mixed simazine at rates of either 2.2 + 0.8 or 3.4 + 1.1 kg a.i. per ha−1, respectively. These treatments were not injurious to either species and consistently resulted in the highest growth indices. No injury was detected when additional liners of boxwood were planted in the treated plots at the termination of the experiment. Chemical names used: 4-(dipropylamino)-3,5-dinitrobenzenesulfonamide (oryzalin); 6-chloro-N,N’-diethyl-1,3,5-triazine-2,4-diamine (simazine); and 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide (metolachlor).
Abstract
A method of obtaining systematic records of the growth arising at each node on grape vines (Vitis vinifera L. or interspecific hybrids including this species and various American species of Vitis) is described and illustrated. Derived variables which can be calculated from these records are listed and a code is given which enables construction of tables of the derived variables by computer.