Foliar spraying was found to be an effective method to rapidly increase boron levels in most vegetative and reproductive tissues in grapevines. The reduction of fruit-set deficiency symptoms with a pre-bloom or bloom spray was immediate but not complete. Foliar sprays applied during the previous fall were more effective in reducing such symptoms than pre-bloom or bloom sprays. This may be due to the earlier incorporation of boron in reproductive tissues, especially dormant buds. Grapevine foliage is also more tolerant to boron postharvest in the fall, when 1 pound per acre of actual boron can be safely applied. Spring and summer sprays of boron should be limited to 1/2 pound per acre per application to avoid phytotoxicity.

Fertilizer use in California agriculture has been under recent scrutiny regarding its impacts on air, surface water and groundwater quality. In June 2007, we surveyed almond growers to assess their plant nutrition practices, identify opportunities for improvement, and target research and extension needs. The majority of respondents, particularly those with large almond acreages, used fertigation to apply nitrogen; applied nitrogen coincident with periods of maximal plant demand; and collected annual tissue samples for analysis. While the survey results suggested broad compliance with the best-available management practices and are likely to indicate good nutrient-use efficiency, they also suggested that growers are uncertain about current practices to monitor orchard nutrient status and would value additional information to enable greater precision in fertilization rates and timing.

”Large bug” damage to pistachio nuts varies by season, as well as among insect species and development stages, with larger bugs typically causing more damage than smaller bugs. We investigated pistachio damage by three large bug species (leaffooted bug, redshouldered stink bug and flat green stink bug) at different development stages and throughout the season, using field surveys and cage studies. Before fruit set occurs in June, most damaged nuts are dropped from the cluster without reducing fruit load. The midseason period (June to July) is the most critical because the damaged nuts remain in the cluster. After shell hardening, the kernel is largely protected from bug feeding.