Disease Archives - West Coast Nut





Disease



Managing and Controlling Canker Diseases in Almonds and Walnuts

By Cecilia Parsons Associate Editor

Options to control Botryospaeria (BOT) diseases in tree nut crops include good sanitation and cultural practices to reduce the amount of inoculum in the orchard. University of California plant pathologist Themis Michallides covered the range of BOT diseases that affect walnut, pistachio and almond trees and how growers can reduce infection at the South Valley Nut Conference in Tulare.   Panicle and Shoot Blight of Pistachio Panicle and Shoot Blight of pistachio was discovered in 1984 in a commercial orchard in northern California and has become a disease of major importance. Buds infected by B. dothidea either will not emerge or will emerge, but the flower or shoot eventually dies. Symptoms of the infection are dark lesions at the base of shoots, rachises and mid ribs of leaves. Later in the growing season, brown, blighted shoots and leaves are easily seen among healthy foliage. Buds are highly susceptible to infection...

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Distribution of Chlorosis in Almond Orchards

Distribution of Chlorosis in Almond Orchards

By: Elizabeth J. Fichtner, Farm Advisor, UCCE Tulare and Kings Counties;
and Mae Culumber, Farm Advisor, UCCE Fresno County,
and Bruce Lampinen, Extension Specialist, UC Davis

The first step in assessing the cause of canopy chlorosis and decline in an orchard is mapping the distribution of the symptoms. If a pattern of chlorosis is similar across irrigation lines, then the cause of the problem may be related to over—or under—watering. Two scenarios present themselves regularly during summer farm calls: a) terminal tree chlorosis, and b) within row tree chlorosis (Figures 1 and 2). Figure 1. A) Chlorosis of end tree indicates excessive water on last tree in row; B) Chlorosis of overall orchard with healthy tree at end of row indicates overwatering at orchard level, and appropriate water to end tree. (Photos: B. Lampinen   Terminal Tree Chlorosis   In some orchards, the terminal tree along the irrigation line may become chlorotic and decline in advance of mortality. If terminal tree chlorosis is a trend throughout the orchard, it is worth assessing the sprinkler distribution at...

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Best Management Practices for Fungal Disease in Almonds

Best Management Practices for Fungal Disease in Almonds

By Cecilia Parsons, Associate Editor

Fungal disease management in almonds requires year-round vigilance.   The overall process for integrated pest management of fungal diseases calls for knowledge about the life cycle of the disease, the crop and environmental triggers.   Emily Symmes, University of California Cooperative Extension (UCCE) Integrated Pest Management (IPM) advisor in the Sacramento Valley,  said actively assessing all stages of a fungal disease, monitoring and tracking weather patterns will help growers be proactive in disease management.   Speaking at the Mid Valley Nut Conference in Modesto, Symmes noted one more key components of a good IPM program is evaluation of fungicide treatments done over the past year.   Growers advised to have a ‘game plan’   “Make a note of what happened, what worked and what didn’t work in your IPM program to help you plan for next year,” she said.   Moisture and temperature are the drivers for fungal diseases. Rain...

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Everything you Need to Know About Thousand Cankers Disease of Walnuts

1,000 Cankers Disease: Everything You Need to Know For Walnuts

By Mohammad Yaghmour, Area Orchard Systems Advisor Kern Co
and Elizabeth Fichtner, UCANR Advisor Tulare and Kings Cos

The walnut tree (Juglans sp.) is well known for its valuable wood and timber quality and its nutritious nut.  Different native species of walnut are an important part of the ecological system in North America.  Eastern black walnut (Juglans nigra) is native to eastern North America from the northeast in Vermont and southern Ontario to Minnesota and south to Florida.  It also ranges east from the Atlantic coast to central Texas except the Mississippi River Valley and Delta.  Juglans nigra has an important economic value estimated at more than $500 billion for its wood and timber alone.  Among the other species that are considered native to the US with natural range are Arizona walnut (Juglans major), Texas walnut (Juglans microcarpa), and California black walnuts (Juglans californica and Juglans hindsii). In California, there are two native ranges of California back walnut species; Southern California black walnut (J. californica) and Northern California...

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Almond Disease and Control

Almond Disease and Control

By Julie R. Johnson, Contributing Writer

From planting to maturity and crop production, almonds trees can be host to a plethora of diseases, be it bacterial, fungal, viral, parasitic or phytoplasmal. These diseases and how to control them was the topic of Dr. Jim Adaskaveg's presentation during this year's North Valley Nut Conference hosted by West Coast Nut in conjunction with the UCCE Butte/Glenn Counties Almond and Walnut Day at Silver Dollar Fairgrounds in Chico. Adaskaveg, professor and plant pathologist with the Department of Plant Pathology, UC Riverside, who specializes in foliar disease of almonds and other tree crops, shared the springtime diseases of almond that can be problematic in a wet spring season are blossom blight, jacket rot, anthracnose, shot hole and bacterial spot. Late spring-summertime diseases include scab, alternaria, leaf spot, anthracnose, rust and hull rot. In an effort to control these and other almond diseases, Adaskaveg emphasized monitoring and risk assessment by determining...

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