Search Results
Abstract
In fungicide tests using recommended rates of fungicide on peach [Prunus persica (L.) Batsch], benomyl in a full season schedule was significantly better than captan against scab and brown rot in 3 out of 4 tests. A 6 application schedule, omitting several cover sprays, was never significantly better than the full captan schedule in the same tests. Bloom sprays did not result in improved brown rot control in 5 tests.
Abstract
Peach seedlings [Prunus persica (L) Batsch] were grown in liquid culture with 0,1,4, 7 and 10 Mg/ml Fe++. After 6 months, the plants were inoculated with Pseudomonas syringae van Hall, the causal agent for bacterial canker, or water, and cankers were measured over a 5 month period. Plants not receiving iron were chlorotic and smaller than those grown in 1,4, 7 μg/ml of iron. Ten μg/ml of Fe++ reduced plant weight when compared to the 1 μg/ml rate. Plants receiving no Fe++ developed the longest bacterial cankers. No significant differences in canker length occurred between treatments containing Fe. In the 0 and 1 μg/ml rate, P. syringae was recovered farther from the inoculation site and after a longer time following inoculation than in other rates of Fe++. P. syringae was not recovered from water inoculated seedlings. The possible relationship of these findings to peach tree short-life is discussed.
Abstract
Twenty-seven cultivars of peach [Prunus persica (L.) Batsch] and 4 seedling clones were evaluated over a 3 year period for susceptibility to gummosis disease caused by Botryosphaeria dothidea (Moug. ex Fr.) ces. & de Not. ‘Harbrite’ was highly resistant while ‘Pekin’, ‘Harmony’, ‘Redskin’, ‘Harken’ and ‘White English’, a seedling clone, exhibited some degree of resistance. All other cultivars were susceptible.
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
‘Spalding’ pear (Pyrus sp. Nak) has been released to provide a good quality pear cultivar for home planting in the Piedmont area of the southeast where fire blight is a major problem.
Seedlessness is an important breeding objective of most citrus scion improvement programs, but production of quality seedless triploid citrus via interploid crosses has historically been limited by the low quality of available tetraploid parents. Production of tetraploid hybrid parents from elite diploid scion cultivars via protoplast fusion is now a practical strategy, and numerous hybrids can be produced on a timely basis from a wide range of parents. Such hybrids can be used as pollen parents in interploid crosses to generate improved seedless triploid fresh fruit cultivars. Herein we report the production of 15 such hybrids from 17 different parents, including sweet orange [Citrus sinensis (L.) Osbeck], mandarin/tangerine (C. reticulata Blanco), grapefruit (C. paradisi Macf.), pummelo [C. grandis (L.) Osbeck], tangor (C. reticulata × C. sinensis), and tangelo (C. reticulata × C. paradisi) germplasm. All hybrids were confirmed by cytological and RAPD analyses, and have been budded to selected rootstocks to expedite flowering.