Subtropical Fruit Crops Research & Education
University of California
Subtropical Fruit Crops Research & Education

Posts Tagged: lemon

The Future of Citrus?

Growers of one of Florida's signature citrus crops, the grapefruit, may see more production and possibly less of the deadly citrus greening disease. Researchers have worked for four years, growing grapefruit under protective screens on a 1-acre experimental plot of trees at the University of Florida Institute of Food and Agricultural Sciences, and they're seeing encouraging results.

UF/IFAS scientists and a few commercial growers have used the system, known as “CUPS,” or “Citrus Under Protective Screens,” for a few years. They're trying to keep the dangerous Asian citrus psyllid away from citrus trees. Infected psyllids can transmit the deadly greening disease to citrus. So far, so good. They're noticing higher grapefruit yields and no psyllids or greening.

Florida grapefruit production has been drastically reduced by citrus greening, also known as Huanglongbing (HLB). In Florida, grapefruit production has gone down from 40.8 million boxes in 2003-2004 to 4.9 million boxes in 2018-2019, according to the USDA.

Arnold Schumann, a UF/IFAS soil and water sciences professor, leads the “CUPS” experiment at the UF/IFAS Citrus Research and Education Center in Lake Alfred, Florida.

And right now, he sees reason for optimism. Schumann is studying how well grapefruit grows in the 1.3-acre facility at the CREC.

Four years of data show grapefruit that exhibit no signs of greening, Schumann said. Researchers planted ‘Ray Ruby' grapefruit trees in August 2014. By December 2018, the trees had produced 2,100 boxes of grapefruits per acre, Schumann said. That's 525 boxes per acre per year on average, but Schumann notes that trees are less productive in the initial two years after planting. In years 3 and 4, the CUPS grapefruit yields were 797 and 892 boxes per acre, respectively. Currently the average yield for Florida grapefruit is about 166 boxes per acre per year, according to the USDA.

“HLB reduces profits for fresh citrus producers in many ways,” Schumann said “Production costs are higher due to increased needs to use pesticides and fertilizers, and fruit production is harmed by stunted tree growth, reduced fruit set and pre-harvest fruit drop, among other factors.”

The CUPS experiment at the Citrus REC has demonstrated that nearly all those harmful effects of HLB can be addressed, Schumann said.

“During the past five years, we have learned much about optimizing horticultural practices and pest and disease management for red grapefruit grown in CUPS,” he said.

Scientists focus on producing high yields with premium grades for the fresh fruit market.

“Our understanding of fresh fruit quality has been honed by our partnership with the Dundee Citrus Growers Association, which harvested and shipped our CUPS grapefruits and tangerines for the past two seasons,” Schumann said “Most importantly, fruit grown in CUPS should all be ready to sell, and our grapefruit and tangerine harvests have achieved 100 percent pack-out. For grapefruits, the fruit size is very important because it greatly affects the selling price.”

One reason for the good yield is the grapefruit's ability to adapt to the higher daytime temperatures under the protective covers, he said.

Other reasons for the increased productions include:

  • High-density planting.
  • A hydroponic system with trees growing in pots, instead of soil and inducing early, large blooms.
  • Drip fertigation – a combination of fertilizer and irrigation -- applied several times a day.

CUPS hydroponic grapefruit has all the important attributes for fresh fruit production: high yields of HLB-free fruit, large fruit size, consistent yields and early maturity, Schumann said.

“The experiments at the CREC focused on proving that the CUPS concept was viable,” Schumann said. “Trees were grown mostly in containers, using hydroponics and very high-planting densities.

A couple of Florida growers are using the CUPS method for grapefruit, although it's too soon to know their results, Schumann said.

Scientists are not yet recommending the intensive production system used at the CREC experiment for commercial CUPS, although one grower in Hardee County is already experimenting with hydroponics and container-grown grapefruits, tangerines and navels under cover, Schumann said.

“Our aim is to maximize fruit production and quality in commercial CUPS with trees grown in the ground at moderately high-planting densities,” he said. “We want to document the most successful methods in a CUPS production guide and to update it as we learn more.”

For more information:
Brad Buck
University of Florida
Ph: +1 (352) 294-3303
bradbuck@ufl.edu
www.ifas.ufl.edu

Photo: Honey Murcott mandarin trees grow in 7-gallon pots at 1,361 trees per acre in the Citrus Research and Education Center screen house. Photo credit: Schumann, 2017

Citrus CUPS
Citrus CUPS

Posted on Friday, May 3, 2019 at 6:30 AM
Tags: citrus (310), citrus under protective screens (1), cups (1), lemon (94), mandarin (66), orange (67)

How Wierd Can Lemons Get?

In a recent post about lemon shape being affected by high temperatures 

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=29443

a grower sent an image of what I thought was  a blurred view of something that was circled.  I responded saying that I couldn't make it out, and a better image should be sent.

The grower resent the image, but this time it was about the long yellow thing in the background that was being asked about.  The tree is planted next to a chile pepper plant and the question was whether the shape was affected by the chile proximity.

The grower had never seen anything like it before and I haven't either.  But rack it up to the high temperature wave during flowering and the rapid fruit growth period and hormones gone amuck.  if temperature extremes become more common, unusual fruit shapes will likely become more common.

 

Posted on Friday, March 22, 2019 at 7:43 AM
Tags: citrus (310), climate change (4), hormones (1), lemon (94)

Different Lemon Shape

Sometimes we don't see things that are not uncommon, but suddenly catch our eye.  A recent lemon harvest of a trial in the Central Valley turned up lots of fruit with enlarged nipples on the stylar end.  These are from a 'Limoneira 8A' rootstock trial.  Not all of of the fruit was like this, but all of the rootstocks had these fruit, so it wasn't a rootstock effect.

On asking around it turns out, this happens in other places, for example on Spanish fruit:

And on Australian fruit:

And even in many normal years and orchards there is some of this special fruit

During the 2018 spring bloom there were several heat waves that hit citrus growing areas.  Dr. Mary Lu Arpaia, UCR Fruit Specialist, surmises that high temperatures make for elongated fruit and quite likely impact cell division at the stylar end, as well.  So the more heat spells during bloom, it's likely that we will see more of this fruit shape.  It's still good to eat.

Posted on Wednesday, March 6, 2019 at 6:34 AM
Tags: citrus (310), climate change (4), heat (5), lemon (94)

ACP and HLB News

News from the Ventura County ACP-HLB Task Force

Winter 2019 area-wide treatment cycle has begun

This is a reminder that the Winter 2019 area-wide management (AWM) treatment window opened Jan.7. You are encouraged to file pesticide use reports (PURs) electronically through CalAgPermits, Agrian, or another system that allows treatments reports to be rapidly filed and recognized. Treatment reminders will be emailed (mailed for those without an email record) about 2-3 weeks prior to the treatment window. In some instances, our contact list may only have contact information for your farm manager, pest control advisor, or pest control operators. If you are not receiving emails, please contact one of your grower liaisons (see contact information below) to receive information about ACP, HLB and your citrus.

Website redesigned

The Citrus Pest & Disease Program (CPDPP) launched a redesign of its website to provide members of California's citrus industry easier access to the key maps, regulatory updates and events they need to stay informed on the fight against HLB in California. The website is at www.citrusinsider.org.

HLB confirmations continue to increase

At least 1,024 residential trees had been confirmed as infected with HLB as of January 2019. No HLB-positive trees have been found in commercial groves. The HLB quarantine boundaries and the latest tally of HLB confirmations, updated weekly, is available online at https://citrusinsider.org/maps-and-quarantines/.

Report neglected and abandoned citrus

Help prevent neglected and abandoned citrus from serving as a breeding ground for ACP and the spread of HLB by reporting its location County Agricultural Commissioner's office at (805) 388-4222. If your citrus is not worth the resources required to protect it from ACP and HLB, it may be a good time to consider removing the trees. Tree-removal assistance is offered to small growers through the California Citrus Mutual and Bayer's ACT NOW program. For more information contact Joel Reyes at  jreyes@cacitrusmutual.com or (559) 592-3790.

 

Calendar

UCR Citrus Day (Jan. 29)

This year's UC Riverside Citrus Day will be on Tuesday, Jan. 29. Agenda and registration information can be found by clicking here.

International Research Conference on HLB/Citrus Virologist Conference (March 10-15)

The joint International HLB and Citrus Virologist conference will be at the Riverside Convention Center in Riverside, CA. Registration and more information can be found here.

Citrus Pest and Disease Prevention Committee meeting (March 12)

The CPDPC is charged with advising the state on management of the Citrus Pest and Disease Prevention Program. The CPDPC and subcommittee meetings are open to the public, and options for participation include in person or by webinar and conference call. Click here to view and register for upcoming committee and subcommittee meetings. Attendance is free. 

 

esources

University of California ACP area-wide materials list and ACP monitoring protocols

Movement of bulk citrus materials list

Ventura County AWM maps and schedule

Citrus Pest and Disease Prevention Program

Ventura County ACP-HLB Task Force mailing list signup

 

Contact your grower liaisons if you have additional questions: 

 

Sandra Zwaal

szwaal2@gmail.com

(949) 636-7089

 

Cressida Silvers

cressidasb@gmail.com

(805) 284-3310

hlb defprmed citrus
hlb defprmed citrus

Posted on Friday, January 25, 2019 at 6:29 AM
Tags: acp (77), asian citrus psyllid (53), citrus (310), hlb (60), huanglongbing (61), lemon (94)

Rootey Tootey - Citrus Fruitey!!!

Grower and the Public are invited to see, taste and hear about the citrus fruits and trees that make an industry and an iconic fruit in this State.  There are two separate days, One for Growers and One for the general Public.  Note the two different days and Pick your  special day.

 

Citrus Growers - Current and Future

Date: December 14, 2018

Time: 9:00 AM - 12:00 PM

Contact: Jasmin Del Toro: 559-592-2408 ext 1151

Sponsor: Lindcove Research and Extension Center

LocationLindcove Research and Extension Center

Event Details

Citrus growers and other Ag professionals are invited to attend the Citrus Fruit Display and Tasting on Dec 14, 2018. You can discuss new low seeded citrus varieties with Dr. Mikeal Roose and ask UC advisors Craig Kallsen and Greg Douhan your citrus questions. In addition to taste-testing fruit, there will be a walking tour at 10:00 AM starting with a presentation of the Citrus Clonal Protection Program by Dr. Georgios Vidalakis, continuing on to the demonstration orchard with Dr. Tracy Kahn who will discuss varieties and a tour of the new lemon variety trial by Dr. Roose.

Directions: Take Highway198 east to Mehrten Drive (approximately 15 miles) and follow the signs to our Event. The University of California, Lindcove Research and Extension Center is located at 22963 Carson Avenue, Exeter, CA.The Conference Center is located at the end of Carson Avenue on the right. If you have any questions please contact Jasmin Del Toro at 559-592-2408  ext 1151 or jzdeltoro@ucanr.edu

 

 Grower day schedule of events 2018

 Public

Date: December 15, 2018

Time: 9:00 AM - 12:00 PM

Contact: Jasmin Del Toro: 559-592-2408 ext 1151

Sponsor: Lindcove Research and Extension Center

LocationLindcove Research and Extension Center

Event Details

The general public is invited to join us for a family friendly Citrus Tasting Event. You can see and taste more than 100 citrus varieties that are grown at Lindcove Research and Extension Center. Take a bag of fruit home for $10. Choose from Cara Caras, Navels, Mandarins, or assorted citrus from 4 bins located in front of the Conference Center. The Master Gardeners as well as UC Cooperative Extension Advisors will be happy to answer questions from home gardeners and citrus connoisseurs.

Directions: Take Highway198 east to Mehrten Drive (approximately 15 miles) and follow the signs to our Event. The University of Lindcove Research and Extension Center is located at 22963 Carson Avenue Exeter, CA. The Conference Center is located at the end of Carson Avenue. If you have any questions please contact Jasmin Del Toro at 559-592-2408 Ext 1151 or jzdeltoro@ucanr.edu

 Lindcove Fruit Display Tasting-home owners 2018

citrus cornucopia
citrus cornucopia

Posted on Monday, November 5, 2018 at 5:02 AM
Tags: citrus (310), demonstration (1), lemon (94), varieities (3)

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