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) 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.

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
CitrusSyngenta Rejects Monsanto’s Buyout Bid
May 8, 2015
Company says $45 billion offer undervalues future prospects. Read More
NutsHow To Avoid Common Mistakes In Almond Scab
May 6, 2015
By the time the disease is visible in orchards, it could be too late. Read More
NutsTips To Manage Scab In Almonds
May 6, 2015
The right treatment at the right time can make all the difference in scab control. Read More
NutsWest Coast Port Slowdown Impacts Almond Shipments
May 6, 2015
The impact of export disruption could be felt for some time. Read More
NutsProgram Designed To Prevent Bee Colonies From Accidental Pesticide Exposure
May 5, 2015
During the past few decades, the loss of pollinators including honey bees, native bees, birds, bats, and butterflies has posed Read More
CitrusMediterranean Fruit Fly Found In JFK Airport
May 5, 2015
The Mediterranean fruit fly, one of the world’s most destructive pests, was recently intercepted by U.S. Customs and Border Protection Read More
CitrusHow You Can Survive The Mobilegeddon
May 4, 2015
The Mobilegeddon is upon us. No, this isn’t a time to prepare disaster bunkers, or buy canned food in bulk. Read More
The Latest
Fruits$10 Million Available For California Water Conservation…
May 19, 2015
Applications for the California Department of Food and Agriculture’s (CDFA) California State Water Efficiency and Enhancement Program (SWEEP) are now Read More
CitrusHouse Votes To Stop “Flawed” Waters Of The United State…
May 15, 2015
The U.S. House of Representatives approved this week bipartisan legislation that requires the withdrawal of the Waters of the United Read More
CitrusImportant Crop Insurance Deadline Nearing For Growers
May 12, 2015
Specialty crop, other producers need to certify conservation compliance by June 1. Read More
CitrusSyngenta Rejects Monsanto’s Buyout Bid
May 8, 2015
Company says $45 billion offer undervalues future prospects. Read More
NutsHow To Avoid Common Mistakes In Almond Scab
May 6, 2015
By the time the disease is visible in orchards, it could be too late. Read More
NutsTips To Manage Scab In Almonds
May 6, 2015
The right treatment at the right time can make all the difference in scab control. Read More
NutsWest Coast Port Slowdown Impacts Almond Shipments
May 6, 2015
The impact of export disruption could be felt for some time. Read More
NutsProgram Designed To Prevent Bee Colonies From Accidenta…
May 5, 2015
During the past few decades, the loss of pollinators including honey bees, native bees, birds, bats, and butterflies has posed Read More
CitrusMediterranean Fruit Fly Found In JFK Airport
May 5, 2015
The Mediterranean fruit fly, one of the world’s most destructive pests, was recently intercepted by U.S. Customs and Border Protection Read More
CitrusHow You Can Survive The Mobilegeddon
May 4, 2015
The Mobilegeddon is upon us. No, this isn’t a time to prepare disaster bunkers, or buy canned food in bulk. Read More
IrrigationCutting Growers’ Water Hurts All Of Us Who Eat [O…
April 29, 2015
There are no silver bullets when it comes to producing food; you need to have a certain amount of H2O. Read More
University of California-Davis
CitrusWorld’s Best Agriculture Colleges Ranking Revealed
April 29, 2015
Annual report card distinguishes which schools are excelling by subject area. Read More
IrrigationAlmond Growers Scramble To Cope With California Drought
April 28, 2015
Growers of the state’s top nut crop have become a target for residents upset over new urban water restrictions ordered by the governor because of a near absence of snowpack. Read More
CitrusCalifornia Drought Forum Slated For May 5
April 27, 2015
Public comments by growers, ranchers, and other stakeholders are encouraged by state officials. Read More
drought sign water crisis
Apples & PearsDiversification: A Response To Drought [Opinion]
April 27, 2015
With Governor Jerry Brown’s announcement of mandatory use reductions, the general public in California is getting a wake-up call on Read More
FruitsOverturned Truck Dumps Millions Of Bees On Highway
April 22, 2015
The truck with 448 hives was headed to a farm in Washington. Read More
CitrusRecord Number Of Organic Producers In U.S.
April 21, 2015
USDA’s Agricultural Marketing Services says domestic production has increased by 250% across all markets since 2002. Read More
FertilizerVerdesian Life Sciences Introduces New Phosphite-Free P…
April 21, 2015
Product designed as alternative for nut and stone fruit growers with concerns about MRLs. Read More