Archive Nut, Prune and Olive Programs

Back to Sites & Content

Newsletters

 

 Newsletter Articles:

May 2025Archived

 

Field picture submitted by Elizabeth Fichtner

 Links

 

Publications

Fruit Report: Page

Boron (B)

Boron deficiency of stone fruit is rare in the San Joaquin Valley (survey), even though B deficiency has been found in many vineyards in the area. Symptoms that have been observed include shoot dieback and the subsequent development of many side shoots.
View Page
Fruit Report: Page

Chemical Thinning

We have tested dozens of chemicals that have potential for thinning peaches, plums and nectarines. Most are caustic materials that "burn" off flowers when applied at the time of bloom.
View Page
Fruit Report: Page

Mechanical Thinning

We have tried several approaches to mechanically thin peach, plum and nectarine flowers or fruit. These include trunk shakers to remove flowers or fruit and a drum shaker that has vibrating rods inserted into the canopy to remove developing fruit.
View Page
Fruit Report: Page

Thinning Early

Generally, the earlier the thinning the better the improvement in fruit size and/or yield. Thus, we have demonstrated that blossom thinning can increase fruit value by as much as $2,000 per acre compared to fruitlet thinning (1997 KTFR Blossom Thinning Summary).
View Page
Fruit Report: Page

Arsenic (As)

Peach trees are very sensitive to arsenic toxicity. The disorder has been found in several peach and nectarine orchards in the San Joaquin Valley. The toxicity is often caused by past use of arsenic based pesticides and herbicides, especially where grape vineyards were previously planted.
View Page
Fruit Report: Page

Sand Tanks

In 1999 we obtained 60 large (11' x 8' x 4' deep) plastic tanks and buried them in the ground at Kearney. We filled them with clean sand and planted a Zee Lady peach, Grand Pearl nectarine and Fortune plum in each.
View Page
Fruit Report: Page

Calcium (Ca)

Calcium deficiency has never been identified in California peach orchards. Most soils in the San Joaquin Valley are abundantly supplied with Ca and leaf samples generally show levels well above the deficiency threshold (1.0%).
View Page
Fruit Report: Page

Zinc Studies with Seedlings

Using Nemaguard seedlings growing in sand, we conducted a series of experiments comparing different zinc formulations. The seedlings were grown with a nutrient solution containing no zinc until deficiency symptoms were observed.
View Page
Fruit Report: Page

Foliar Urea

We have conducted research to show that foliar urea sprays in the fall can contribute to the total nitrogen needs of a peach or nectarine tree.
View Page