Beating BOT Blight In Pistachios

Many of California’s pistachio growers were taken by surprise when an outbreak of Botryosphaeria blight, or BOT blight, struck their orchards this past season. Boytryosphaeria is spread primarily through moving water in orchards, and late rains in the state last year helped spread Botryosphaeria dothidea spores, initiating multiple infections, says Themis Michailides, a plant pathologist at the University of California’s Kearney Agricultural Center.

Researchers have discovered that more species of Botryosphaeriaceae fungi are involved in BOT blight than were initially thought. According to Michailides, these species are abundant among nut crops and other hosts in California, and they accumulate in the bark of older trees, even healthy branches. When dead clusters, cankers, buds, and shoots accumulate on the trees, pathogens can survive and produce spores in these cankers for six years or longer. If present, the disease can be spread via insect transmission, pollen, and pruning equipment, too.

Monitoring And Management

Michailides says growers should do a bud monitoring (BUDMON) (click here) test to determine how much Botryosphaeria, if any, is present in orchards before pistachio shoots and blooms emerge, usually in February or March. “And watch the weather carefully,” he adds. “If the prognosis is for rains that coincide with full bloom, growers will need to apply a bloom spray before the rains.” Michailides recommends monitoring leaf wetness and temperature to determine the best times and how much to spray.

Another option is overnight freezing incubation (ONFIT), which is usually done in June (click here).

Growers should remain vigilant and look out for symptoms like blighted shoots and clusters. Blackening of the main shoot and rachis of clusters is reason for concern. “Learn how to distinguish Botryosphaeria from Botrytis shoot and blossom blight,” Michailides says. “Beige or buff color powdery spores are present at the base of shoots in the case of Botrytis infections, while Botryosphaeria will have pycnidia inside the plant tissues.”

Topics:

Leave a Reply

One comment on “Beating BOT Blight In Pistachios

  1. […] Beating BOT Blight In Pistachios | Growing Produce – How To Manage Tomato Yellow Leaf Curl … 4 New Citrus Rootstocks To Grow On; … Many of California’s pistachio growers were taken by surprise when an outbreak of Botryosphaeria blight, or BOT blight, struck their orchards this past season. […]

Nuts Stories

CitrusEPA Launches Program To Reduce Pesticide Drift
October 22, 2014
The voluntary star-rating program aims to protect people, wildlife and the environment. Read More
CitrusAgriculture, Interior Departments Partner To Measure Conservation Impacts On Water Quality
October 22, 2014
Goal is to provide science-based information for watershed wellness. Read More
CitrusIt’s Time For Young Farming Leaders To Engage [Opinion]
October 21, 2014
Florida Grower editor Frank Giles says there are capable and talented youths in the ag field ready to step up and take the reins. Read More
CitrusBayer CropScience Launches New Award To Recognize Produce Industry Innovators
October 21, 2014
Award recognizes innovation that enhances the role of produce in creating better lives. Read More
CitrusReport: Major Food And Agriculture Employers Can’t Fill Vital Jobs
October 21, 2014
Current shortage of young farming professionals means ample employment opportunity for the next generation. Read More
NutsAlmond Growers To Promote Bee Health
October 16, 2014
Almond Board of California announces comprehensive Best Management Practices. Read More
NutsKeep In Mind Availability Of Soil Fumigants
October 15, 2014
Almond growers must be aware of restrictions pertaining to soil fumigants prior to replanting. Read More

The Latest

FruitsCalifornia Growers Sue State Over Drought
October 30, 2014
They claim the State Water Resources Control Board illegally denied water deliveries. Read More
FruitsHuge California Drought Meeting Planned
October 29, 2014
State, federal officials to meet as forecasts for the coming year look bleak. Read More
CitrusNOAA’s Winter Weather Outlook Runs Hot And Cold
October 27, 2014
Repeat of last year’s extreme cold and snow events east of the Rockies unlikely. Read More
CitrusEPA Launches Program To Reduce Pesticide Drift
October 22, 2014
The voluntary star-rating program aims to protect people, wildlife and the environment. Read More
CitrusAgriculture, Interior Departments Partner To Measure Co…
October 22, 2014
Goal is to provide science-based information for watershed wellness. Read More
CitrusIt’s Time For Young Farming Leaders To Engage [Op…
October 21, 2014
Florida Grower editor Frank Giles says there are capable and talented youths in the ag field ready to step up and take the reins. Read More
CitrusBayer CropScience Launches New Award To Recognize Produ…
October 21, 2014
Award recognizes innovation that enhances the role of produce in creating better lives. Read More
CitrusReport: Major Food And Agriculture Employers Can’t Fi…
October 21, 2014
Current shortage of young farming professionals means ample employment opportunity for the next generation. Read More
NutsAlmond Growers To Promote Bee Health
October 16, 2014
Almond Board of California announces comprehensive Best Management Practices. Read More
NutsKeep In Mind Availability Of Soil Fumigants
October 15, 2014
Almond growers must be aware of restrictions pertaining to soil fumigants prior to replanting. Read More
CitrusScientists Uproot Common “Superweed” Myths
October 15, 2014
A new fact sheet is available that explores the truth behind two fallacies.   Read More
CitrusFarm Bureau Urges Senate To Ditch Proposed Water Rule
October 8, 2014
Farm Bureau says the time is now to have the proposed water rule withdrawn. Read More
NutsGeorgia Universities Evaluating New Crop Monitoring Tec…
October 7, 2014
They receive USDA grant to work with company to measure effectiveness of Internet-based devices in growing pecans. Read More
Food SafetyCenter For Produce Safety To Fund 14 Projects
October 7, 2014
The objective of the new grant awards is to provide the industry with practical research that can be used at all levels of the supply chain. Read More
FruitsUSDA Expands Access To Credit To Help More Beginning A…
October 7, 2014
Changes increase eligibility and financing options. Read More
Citrus2014 Irrigation Show To Highlight Education
October 6, 2014
The conference, to be held in Phoenix, AZ, brings together all aspects of irrigation and water management: education, certification, networking, and innovative technologies. Read More
Farm ManagementSpecialty Crop Producers Score Nearly $118 Million In G…
October 2, 2014
Via 2014 Farm Bill, USDA seeks to bolster major driver in U.S. economy.   Read More
NutsNew Walnut Budding, Grafting, and Planting Video Releas…
October 1, 2014
Lake County nurseryman Alex Suchan, who has been grafting trees for two-thirds of a century, is the star. Read More