A Need for Winter Irrigation?
Since mid-January the lack of rainfall has come to the forefront of our minds, and we have an updated precipitation picture as of late February 2020. Continue reading
Author Archives: Luke Milliron
Don’t tie so close! Plus, other walnut staking considerations
Seeing young walnut trees tied so tightly to a stake that they appear glued is not an unusual site. However, tying a young tree tightly to the stake can cause multiple problems. Continue reading
Preparing for Extreme Events: Flood
Flooding from unprecedented flows of the Sacramento and Feather Rivers in early 2017 through spring, resulted in extensive orchard damage. Although there is little you can do to prepare against the most extreme flooding, some practices can help to reduce damage. Continue reading
Get those Gophers!
Walk your orchard blocks to look for fresh horseshoe shape and plugged side hole of pocket gopher mounds. This postharvest period is a key time to manage your gopher problem and make sure you’re giving yourself a clean slate for 2020! Continue reading
Postharvest irrigation in a dry autumn?
It is important to consider irrigation of perennial tree crops leading up to dormancy to foster carbohydrate storage in the trees and to guard against the occurrence of freezing temperatures in dry orchards putting them at more risk to cold injury. Continue reading
Prune Rootstocks & Bacterial Canker Susceptibility
Survival is the number one priority of a new orchard planting. Bacterial canker plagues many young prune orchards and rootstock selection can make a major impact on bacterial canker susceptibility. Learn which rootstocks have 100% survival in a UC prune rootstock trial at a high bacterial canker pressure site. Continue reading
Hull split timing differences by rootstock?
You’re certainly familiar with the differences in almond hull split and subsequent harvest timing between different varieties. A typical case of this can be observed with early splitting and harvest of Nonpareil relative to other later varieties. However, you may not often think about differences in hull split influenced by rootstock. Continue reading
Yellowing/Collapsing Walnut Trees? Pt. 2 Yellowing Howard Problem
The yellowing Howard problem is one specific instance of waterlogging induced root death. Howard appears sensitive to problems following cool, wet springs. The key management solution to the yellowing Howard problem is irrigation management. Continue reading
Yellowing/Collapsing Walnut Trees? Pt. 1 Water Logging
A single yellowing walnut tree in an otherwise healthy orchard has been a frequent sighting when driving along the roadways of the Sacramento Valley this summer. These yellowing trees have also been common this summer. The most likely cause of this yellowing and tree collapse was waterlogging induced root death. Continue reading
Howard Nut Drop
During about the second or third week in June, many Howard walnut trees experienced nut drop of perhaps as many as 100 nuts per tree, with many trees losing no more than 60 nuts per tree. These nuts were full size with the shell beginning to harden. Cutting open an immediately dropped nut, you could see darkening of the inside watery kernel material. Several possible causes are explored in this article. Continue reading
Tighter Spacing and Greater Light Interception in Prunes
Luke Milliron, UCCE Farm Advisor, Butte, Tehama, and Glenn Counties; Franz Niederholzer, UCCE Farm Advisor, Colusa, and Sutter-Yuba Counties; Dani Lightle, UCCE Farm Advisor, Glenn, Butte, and Tehama Counties; Katherine Jarvis-Shean, UCCE Farm Advisor, Yolo, Solano, and Sacramento Counties Increased … Continue reading
Walnut Autumn Freeze Event and Spring Regrowth Update, 2018
A sudden autumn freeze event last November is the likely cause of widespread dieback observed in both young and mature orchards in the Sacramento and northern San Joaquin Valleys this spring. Following reports in April of walnut orchards not leafing out, our initial diagnosis was freeze damage. We advisors, specialists, and faculty agree that this initial diagnosis has been further supported after examining additional orchards and weather station sites. Continue reading
Spring Cankers in Prune
In prunes, some years are bacterial canker years, while every year is a Cytospora year. Going into this year, we knew the wet/cold conditions could mean that we were headed into a bacterial canker year. However, diagnosing the dieback we are seeing this spring has brought some surprises. Continue reading
Walnut Orchards Not Leafing Out
From the northern San Joaquin Valley to the northern Sacramento Valley, walnut growers are reporting a widespread and alarming issue of walnut trees not leafing out this spring. The initial hypothesis from researchers is that we are seeing frost damage from mid-November, however the symptoms on mature blocks are both more unusual and more severe than autumn freeze events in recent memory. Continue reading
It was a wet winter! How wet?
Storms throughout the winter and into early spring, have resulted in localized flooding in the Sacramento Valley and left standing water or shallow perched water table in many orchards in the region. This update shows the extent of above-average rainfall in different parts of the Sacramento Valley in January through March. Continue reading