No description available.

No description available.

No description available.

No description available.

Using portable sap flow sensors, the onset and volume of sap moving up the branches of grapefruit (Citrus Paradisi Macfadyen) trees was monitored on an hourly basis. Reference evapotranspiration (ETo) data was obtained from The Arizona Meteorological Network (AZMET). Crop evapotranspiration (ETc) was estimated from soil moisture measurements using a neutron probe. The threshold temperature limits were delineated from an evaluation of the hourly sap flow responses to cold winter and extreme summer temperatures. The heat based crop curve was derived from a correlation of the crop coefficients with heat unit over one crop year. The heat based crop coefficients were found to be similar to crop coefficients derived by other researchers.

Four 'Lisbon' lemon selections from the University of Arizona Citrus Budwood Certification plot were selected for evaluation on Citrus rootstock 'Frost Nucellar', 'Corona Foothills', 'Limoneira 8A' and 'Prior' were selected because of their popularity among Arizona growers or because of the lack of information about their performance under Arizona climactic and edaphic conditions. Trees were planted in 1993. Early results indicate that the 'Limoneira 8A Lisbon' selection is outperforming the other selections in both growth and yield. In a similar trial, five rootstocks were selected for evaluation using 'Limoneira 8A Lisbon' as the scion. Carrizo citrange, Citrus macrophylla, Rough lemon, Swingle citrumelo and Citrus volkameriana were chosen. Trees were planted in 1993. Early results indicate that trees on C. volkameriana are superior to those on other rootstocks in both growth and yield.

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.

Twenty-five plants of each of ten blackberry cultivars from Arkansas and Texas were established at the Yuma Mesa Agriculture Center in spring 1994. All the Arkansas cultivars died. Of the Texas cultivars, 'Rosborough' and 'Womack' performed the best, followed by 'Grison' and 'Brazos'. Important cultural practices, harvesting practices and potential marketing strategies are discussed

Boron was applied as a foliar spray to pecan trees in a pecan orchard located in Cochise County. Single or repeated application prior to pollination did not affect nutlet set. Leaf analysis indicated that the boron levels in all trees were in the sufficient range for optimum growth and production.

Vivaparity, a significant quality- reducing condition found in pecans grown in warm, temperate climates, was evaluated by location of the pecan nut within the cluster in two varieties, "Wichita " and "Western Schley". Percentage vivaparity was not affected by position.