Citrus Research Report 1997http://hdl.handle.net/10150/2132102024-03-29T08:47:02Z2024-03-29T08:47:02ZPreliminary Results Regarding the Effects of Foliar Applied Roundup on Lemon Physiology and YieldMcCloskey, William B.Wright, Glenn C.http://hdl.handle.net/10150/2205672020-04-02T09:43:07Z1997-11-01T00:00:00ZPreliminary Results Regarding the Effects of Foliar Applied Roundup on Lemon Physiology and Yield
McCloskey, William B.; Wright, Glenn C.
Wright, Glenn
The effect of Roundup on lemon trees was evaluated by repeatedly spraying 0.5, 0.75, 1, 1.25, and 1.5 lb a.i/acre on the bottom 20 to 24 inches of the tree canopies. Leaf injury symptoms, flower and fruit counts, and yield data were collected The Roundup applications caused significant leaf injury in the sprayed area of the canopies and there was significant defoliation of branches at the higher Roundup rates. In 1996, flower and fruitier counts were not affected by the Roundup applications. However, flower and fruitier counts in 1997 in the sprayed zone of the canopy were significantly reduced by Roundup and the effect increased with increasing Roundup rate. The 1996 yield data indicated that the Roundup applications did not significantly affect lemon yield, however, the effect of Roundup on the 1997 flower and fruitier counts suggests that there may be a yield effect in 1997. The preliminary data suggest that accidental drift of Roundup on to lemon trees when spraying weeds on the orchard floor has no short-term effect on grove productivity but this conclusion must be substantiated by further data collection.
1997-11-01T00:00:00ZEffects of Long-Term Preemergence Herbicide Use on Growth and Yield of CitrusMcCloskey, William B.Maurer, Michaelhttp://hdl.handle.net/10150/2205242020-04-02T10:24:13Z1997-11-01T00:00:00ZEffects of Long-Term Preemergence Herbicide Use on Growth and Yield of Citrus
McCloskey, William B.; Maurer, Michael
Wright, Glenn
The effects of several preemergence herbicides at various rates were tested on bearing Redblush' grapefruit trees and non-bearing Navel orange trees. Some of the preemergence herbicides caused foliar injury symptoms on the trees including Hyvar X Diuron, and Krovar I although they did not cause significant yield reductions in the short time period of this experiment. Several herbicides including Solicam, Surflan, and Prowl did not cause foliar injury or reduce yield and provided good weed control for various lengths of time. The Prowl treatments provided the longest period of weed control in the experiment on bearing grapefruit trees.
1997-11-01T00:00:00ZContributions of Beneficial Soil Fungi to Drought Stress Tolerance of Young CitrusFidelibus, MatthewMartin, ChrisStutz, Jeanhttp://hdl.handle.net/10150/2205662020-04-02T08:59:59Z1997-11-01T00:00:00ZContributions of Beneficial Soil Fungi to Drought Stress Tolerance of Young Citrus
Fidelibus, Matthew; Martin, Chris; Stutz, Jean
Wright, Glenn
Four arbuscular mycorrhizal (AM) fungal isolates (Glomus sp.) from disparate edaphic conditions were screened for effects on whole -plant transpiration of juvenile 'Volkamer' lemon (Citrus volkameriana Ten. and Pasq.) plants of similar shoot mass and canopy leaf area. Mycorrhizal and non -mycorrhizal plants were grown in 8 -liter containers for 2.5 months under well- watered conditions before subjection to three consecutive soil drying episodes of increased severity (soil moisture tensions of -0.02 [still moist], -0.06 [moderately dry], and -0.08[dry] MPa respectively). Whole plant transpiration measurements were made on the last day of each soil drying episode and measurements were repeated on the first and second days after re- watering, when soil profiles were moist. The percent root length colonized by AM fungi differed among isolates. Three AM fungal isolates, Glomus sp. 25A, Glomus mosseae (Nicol. & Gerde.) Gerde. & Trappe 114C, and Glomus intraradices Schenck & Smith FL 208-3 increased root length and subsequently increased lemon plant water use. Conversely, plants inoculated with Glomus mosseae 51C did not enhance lemon plant root length nor improve plant water use compared with nonmycorrhizal control plants. Inoculating citrus with AM fungi that promote root extension may reduce plant water deficit stress under field conditions.
1997-11-01T00:00:00ZMolecular Basis of Rootstock-Scion Incompatibility in Macrophylla Decline May Reveal Useful Information for Screening Compatible Rootstock-Scion CombinationsTaylor, Kathryn C.http://hdl.handle.net/10150/2205652020-04-02T08:59:59Z1997-11-01T00:00:00ZMolecular Basis of Rootstock-Scion Incompatibility in Macrophylla Decline May Reveal Useful Information for Screening Compatible Rootstock-Scion Combinations
Taylor, Kathryn C.
Wright, Glenn
Several differentially expressed markers of compatibility or incompatibility were isolated and are being molecularly characterized One marker is present in young Eureka on Macrophylla trees and on Macrophylla decline affected, Eureka on Macrophylla trees, while absent on healthy, Eureka on Macrophylla trees of the same combination. A second marker appears similar to a gene that encodes a Zn-binding homeodomain of a DNA binding protein in plant cells. This particular marker was found in the leaves of healthy trees, but absent in Macrophylla decline trees, which are known to be Zn deficient. Thirty-five markers are being characterized in all.
1997-11-01T00:00:00Z