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Several calls have come in from growers lately about yellow avocado and citrus trees. the yellowing is most common on the late summer flush leaves or can affect the whole canopy on young trees. In severe cases leaves fall.

Pollination ecologists have typically studied a focal plant species and one or a few closely related pollinator taxa, such as bumblebees, which fostered the view that plant-pollinator relationships are highly specialized.

I am amazed how such a simple procedure can go so wrong. For avocado and citrus growers, its time to think about planting in the spring. And every spring and summer I get called out to diagnose trees that are failing. It often turns out that the trees have been planted too deeply.

"We don't need to irrigate, it's winter." This is a commonly held idea, and many years it is true. Adequately timed rains will often meet the needs of avocado trees during the winter period, and in times like last year, even satisfy much of the spring requirement.

Jim Downer is the Environmental Horticulture Advisor in Ventura County Cooperative Extension As growers of thousands of ornamentals we understand that minerals absorbed mostly by roots as ions are essential for plant growth and development.