http://hdl.handle.net/10150/197331 2026-05-20T05:15:21Z http://hdl.handle.net/10150/226098 Rejuvenation of Neglected, Mature "Wichita" Pecan Trees By Corrective Pruning Gibson, Richard; Kilby, Michael Wright, Glenn; Kilby, Mike An attempt was made in 1997 to rejuvenate neglected, mature 'Wichita' pecan trees in a commercial Pinal County grove by applying two types of heading back pruning cuts. The treatments were applied during the dormant season prior to the growing season. The trees were pruned using proven horticultural techniques which included dehorning (cutting main scaffolds to within 2 feet of the trunk) and cutting main scaffolds by 50%. After four years of data, the trees receiving no pruning treatments are producing as well or better than trees to which the pruning treatments were applied. The data suggests that a return to normal irrigation and fertilization practices alone will return neglected, water-stressed trees to normal productivity as early as trees that have been headed-back. 2002-02-01T00:00:00Z http://hdl.handle.net/10150/226097 Effect of fungicide treatments on incidence of powdery mildew of pecan and on pecan nut quality Olsen, M.; Rasmussen, S.; Nischwitz, C. Wright, Glenn; Kilby, Mike Powdery mildew of pecan, caused by Microsphaera ulni, was observed on pecan shucks by the latter part of June 2000 in a commercial pecan orchard near Sahuarita, Arizona. Results of 1999 studies indicated that infection does not reduce nut quality. In order to determine effects of fungicide treatments and to substantiate results from 1999, preventive applications of micronized sulfur and azoxystrobin were initiated on June 8, 2000 in selected clusters in both Wichita and Western varieties. Trials were established in plots that had a high incidence of powdery mildew in 1999. Whole nut weights, kernel weights, or color ratings were not significantly different among clusters of nuts that were treated with fungicides and untreated nuts that were infected with powdery mildew. Percent disease incidence was 100% in untreated clusters, 0% in clusters treated with azoxystrobin every two weeks, and 5.3% (Wichita) and 8.8% (Western) in clusters treated with sulfur three times early in the season. Results indicate that disease did not affect nut weight or quality and that early preventive fungicide treatments are effective in controlling infections. 2002-02-01T00:00:00Z http://hdl.handle.net/10150/226096 Results of Scion and Rootstock Trials for Citrus in Arizona - 2000 Wright, Glenn C.; Peña, Marco A. Wright, Glenn; Kilby, Mike Five rootstocks, 'Carrizo' citrange, Citrus macrophylla, Rough lemon, Swingle citrumelo and Citrus volkameriana were selected for evaluation using 'Limoneira 8A Lisbon' as the scion. 1994-2000 results indicate that trees on C. macrophylla and C. volkameriana are superior to those on other rootstocks in both growth and yield. C. macrophylla is outperforming C. volkameriana. Rough lemon is intermediate, and 'Swingle' and Carrizo’ are performing poorly. For 2000-01, rough lemon trees performed similarly to C. macrophylla and C. volkameriana. In a similar trial, Four 'Lisbon' lemon selections, 'Frost Nucellar', 'Corona Foothills', 'Limoneira 8A' and 'Prior' were selected for evaluation on Citrus volkameriana rootstock. 1994-2001 results indicate that the 'Limoneira 8A Lisbon' and 'Corona Foothills Lisbon' are superior in yield and fruit earliness. Results from another lemon cultivar trial suggest that 'Cavers Lisbon', 'Limonero Fino 49' and 'Villafranca' lemons may be good candidates for plantings as well. Results from three other lemon scion trials, a navel orange cultivar trial and a 'Valencia' orange trial, and a 'Fallglo' mandarin trial are presented as well. 2002-02-01T00:00:00Z http://hdl.handle.net/10150/226074 Organic Lemon Production Zerkoune, Mohammed; Wright, Glenn; Kernz, David; McCloskey, William Wright, Glenn; Kilby, Mike This experiment was initiated in March 2000 to study the feasibility of growing organic lemon in the desert southwest of Arizona. A ten-acre field planted to lemons in 1998 was selected on Superstition sand at the Yuma Mesa Agricultural Research Center. The initial soil test in top 6 inches was 5 parts per million (ppm) NO₃⁻ and 4.9-PPM NaHCO₃⁻-extractable P. Soil pH was 8.7 in the top 6 inches. Seven treatments were applied in randomized complete block design repeated three times. The treatments were control, compost and clover, compost and perfecta, compost and steam, manure and clover, manure and perfecta and manure and steam Leaf tissue analysis indicated that nitrate level was significantly influenced by treatment. Organic insect control treatments for citrus thrips were as equally effective as the non-organic commercial standards. 2002-02-01T00:00:00Z