Experimental Transmission of Citrus Blight

摘要: eight healthy 6-yr-old Pineapple sweet Tucker, D. P. H., Lee, R. F., Timmer, L. W., Albrigo, G., and Brlansky, H. 1984. orange trees on rough lemon rootstock Experimental transmission of citrus blight. Plant Disease 68:979-980. from a grove in Lake Alfred unaffected by blight were pruned transplanted Eight mature, blight-affected (Citrus sinensis) (C. as described. These receptor jambhiri) to an area low incidence. Healthy bearing planted adjacent the donor with age same cultivar next each tree several roots healthy, blighted donors splice-grafted together. An trunks about 1.2 m those equal number control was row. After 3 yr, had donors. Five 10 1-2 cm significantly higher concentrations zinc trunk phloem than controls. 4 seven diameter typical visual symptoms blight, similar wood, lower water uptake, amorphous plugs vessels trunk. Only one corresponding tree. additional developed these symptoms. This is first report experimental similarly row 4.5 Citrus vascular wilt disease under field conditions. Lima unknown cause. Losses Borducchi (6) also graft-transmitted ungrafted controls for root-grafted have been severe, reaching 'zinc accumulation factor" young receptors. 500,000 per year Florida, sources, but At various times during experiment, loss rates individual groves high did not show decline diagnostic techniques used 10-20% (11). Progress Transmission evaluate status donor, research has slow because factor confirmed other studies receptor, trees. Canopy does develop less 5-8 yr (13). In all previous work, no rated scale 0 = old induced artificially 1 mild (leaves small experimentally (10). early or reproduced known deficiency, internodes Rhoads (7) concluded that mature short, slight little thinning nonparasitic disorder after failure It generally agreed foliage), 2 moderate small, graft-transmit propagate disease. malady nontransmissible often flaccid, Even more thoroughly Most concentrated canopy sparse some twig characterized tests became available, bud propagations seedlings propagation reconstitutions reconstituting new Table 1. Diagnostic characteristics sprouted buds affected failed reproduce (9,13). this paper, we present evidence experiment. Feldman Hanks (3) reported reduction can be transmitted experiof root growth mentally Characteristic Date Valuea