Subtropical Fruit Crops Research & Education
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Subtropical Fruit Crops Research & Education

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Weird Chimeras, but Will it Sell?

Nobody messed with this fruit.  This is a real fruit from a real tree from a real backyard sent by a real person

 

The whole group of plants we lump under the taxonomic classification of citrus are really changeable. It's out of this changeability that we get new varieties.  Some of these can be quite fanciful, almost dream like fruit which is where the origin of the name chimera comes from.  Buddha's Hand is a pretty dream-like fruit.

 

 

These changes are a genetic mutation that occurs in a branch or twig, and if that tissue survives, it can produce new shoots (called sports or chimera) with characteristics different from the those of the mother tree.  These mutations can affect the color of the rind or pulp or the shape of the fruit. 

 

 

Leaves on these twigs can have a different shape or size have a variegated color. 

 

 

Mutations can cause the development of multiple buds, creating bunchy growth or “witches' broom.” 

 

 

A chimera can produce an improved crop: some of today's cultivars were propagated from chimeras, such as the variegated pink lemon.

 

 

Usually sports are of inferior quality and should be avoided as propagation material. Prune sports that obstruct normal growth or interfere with harvest. 

But some of them are so weird you just want to keep them around. This one showed up on one and only one tree branch in a lemon orchard. It looks like citrus scab, sort of, but on only one branch of one tree.

 

Some of the changes that you see in a tree can also be symptoms of a whole lot of other problems, like nutrients, Huanglongbing or herbicide damage.  Check out some of the symptoms:http://ipm.ucanr.edu/PMG/C107/m107bpfruitdis.html

Some chimeras are yet to be found out. This image of spiral tattooing showed up for several years ago in a Meyer lemon orchard. It was erratic and inconsistent in a tree, not typical of a chimera.  The orchard was finally removed because it wasn't making money.  Now it just seems like a dream and will never know if it was a true chimera.

 

 

 

Posted on Monday, April 8, 2019 at 7:26 AM

What Will Happen if HLB is Found Near You? Find Out April 16-18

The Citrus Pest & Disease Prevention Program is hosting informational meetings throughout California to inform citrus growers, packers and haulers about what to expect from CDFA's regulatory response if Huanglongbing is found within five miles of a commercial citrus business. Attendees will learn about the regulatory processes an HLB detection would trigger and have time to speak one-on-one with meeting presenters. These educational meetings, named “The State of HLB in California,” will take place on April 16 in Escondido, April 17 in Santa Paula and April 18 in Exeter.

 

Each meeting will cover the following topics:

  • Overview of how Asian citrus psyllids and HLB spread – Dr. Beth Grafton-Cardwell, Entomologist, University of California Agriculture and Natural Resources
  • What toexpectfromCDFAifHLB is found in or near a commercial grove –CDFA
    • Review regulatory response to the following scenarios:
      • HLB is detected in your grove
      • Grove is within 400 meters of HLB detection
      • Grove is within the 5-mile HLB quarantine
    • Overview of what type of compliance paperwork growers, packers, haulers will need if in the 5-mile HLB quarantine zone
  • The current status of ACP and HLB in California – CDFA

After each meeting, there will be time for attendees to speak directly with the presenters and others, as well as gather information from the day's presentations, during an informal “resource fair.”

Meeting Dates and Locations
Note: RSVP is not required but is encouraged. RSVP for one of the following meetings here.

Tuesday, April 16
9 – 11 a.m.
San Diego County Farm Bureau
420 S. Broadway
Escondido, CA 92025
RSVP Here

Wednesday, April 17
10 a.m. – noon
Santa Paula Community Services Building
530 W. Main St.
Santa Paula, CA 93060
RSVP Here

Thursday, April 18
10 a.m. – noon
Exeter Veterans Memorial Building
324 N. Kaweah Ave.
Exeter, CA 93221
RSVP Here

Questions? Contact us at CitrusInsider.org/contact-us.

 

Phioto:

ACP-On-A-Stick

ACP mounted
ACP mounted

Posted on Sunday, April 7, 2019 at 2:06 PM
Tags: acp meeting (1)

Hedgerows Encourage Food Safety?

Food safety:

Dung beetles and soil bacteria reduce risk of human pathogens

Food safety regulations increasingly pressure growers to remove hedgerows, ponds and other natural habitats from farms to keep out pathogen-carrying wildlife and livestock. Yet, this could come at the cost of biodiversity.

New research published today in the Journal of Applied Ecology encourages the presence of dung beetles and soil bacteria at farms as they naturally suppress E. coli and other harmful pathogens before spreading to humans.

Wild and domesticated pig faeces have been known to contaminate produce in the field, leading to foodborne illnesses. Wild, or feral, pigs especially pose a risk of moving around pathogens as farmers cannot control where or when these large animals might show up.

Matthew Jones, who led the research as part of his PhD project at Washington State University, said: "Farmers are more and more concerned with food safety. If someone gets sick from produce traced back to a particular farm it can be devastating for them."

"As a result, many remove natural habitats from their farm fields to discourage visits by livestock or wildlife, making the farmland less hospitable to pollinators and other beneficial insects or birds", he added.

Dung beetles bury faeces below ground and make it difficult for pathogens to survive. To study how this may aid food safety, the entomologist drove a van full of pig faeces along the US West Coast to follow the planting of broccoli at 70 farm fields during the growing season. Broccoli, much like leafy greens, is susceptible to faecal contamination due to its proximity to the ground and the likelihood of humans consuming it without cooking.

The pig faeces were used to attract dung beetles and see how quickly they would clean up. The experiment was carried out at conventional and organic farms, and farms with or without livestock.

The organic farms seemed to attract a diverse range of dung beetle species that were most effective at keeping foodborne pathogens at bay. At conventional fields or those surrounded by pastureland, a less effective and accidentally introduced species (Onthophagus nuchicornis) outweighed the number of native dung beetles.

"We found that organic farms generally fostered dung beetle species that removed the faeces more rapidly than was seen on conventional farms", said Professor William Snyder of Washington State University.

Dung beetles likely kill harmful bacteria when they consume and bury the faeces. Previous research also suggested that these beetles have antibiotic-like compounds on their body.

To validate these findings, the researchers exposed the three most common species found in the field survey to pig faeces contaminated with E. coli. A 7-day laboratory experiment revealed that Onthophagus taurus and Onthophagus nuchicornis, both of which bury faeces as part of their breeding behaviour, reduced E. coli numbers by > 90% and < 50% respectively.

They also found that organic farming encouraged higher biodiversity among soil bacteria, which decreased the survival of pathogens.

"Bacteria are known to poison and otherwise fight among themselves and the same may be happening here", said Snyder.

These results suggest dung beetles and soil bacteria may improve the natural suppression of human pathogens on farms, making a case for reduced insecticide use and the promotion of greater plant and insect diversity.

"Wildlife and livestock are often seen as something that endanger food safety, but our research shows that reducing on-farm biodiversity might be totally counterproductive", Jones concluded.

"Nature has a 'clean-up crew' of dung beetles and bacteria that quickly remove faeces and the pathogens within them, it appears. So, it might be better to encourage these beneficial insects and microbes."

Read more at:

https://phys.org/news/2019-03-food-safety-dung-beetles-soil.html#jCp

DOI: 10.1111/1365-2664.13365

Jones MS, Fu Z, Reganold JP, et al. Organic farming promotes biotic resistance to foodborne human pathogens. J Appl Ecol. 2019;00:1-11.

More information: Jones MS, Fu Z, Reganold JP, et al. Organic farming promotes biotic resistance to foodborne human pathogens. J Appl Ecol. 2019;00:1-11. DOI: 10.1111/1365-2664.13365

Read more at: https://phys.org/news/2019-03-food-safety-dung-beetles-soil.html#jCp
More information: Jones MS, Fu Z, Reganold JP, et al. Organic farming promotes biotic resistance to foodborne human pathogens. J Appl Ecol. 2019;00:1-11. DOI: 10.1111/1365-2664.13365

Read more at: https://phys.org/news/2019-03-food-safety-dung-beetles-soil.html#jCp
More information: Jones MS, Fu Z, Reganold JP, et al. Organic farming promotes biotic resistance to foodborne human pathogens. J Appl Ecol. 2019;00:1-11. DOI: 10.1111/1365-2664.13365

Read more at: https://phys.org/news/2019-03-food-safety-dung-beetles-soil.html#jCp

dung beetle
dung beetle

Posted on Thursday, April 4, 2019 at 6:51 PM
Tags: food saftey (1), hedgerows (2), pigs (1)

Controlling Soil pH with a Grass?

This is an intriguing article that popped up about how to improve blueberry production in alkaline soils.  High pH soils are a major issues for many of our tree crops along the coast.  pH is what controls the availability of most plant nutrients and what bacteria and fungi grow in the soil, creating the biosphere.   So can growing a grass cover crop in our orchards improve lemon and avocado production?

A lawn is better than fertilizer growing healthy blueberries

Intercropping with grasses is an effective and sustainable alternative to chemical treatments for maximizing blueberry yield and antioxidant content in limey soils.

 

Blueberries are prone to iron deficiency - and correcting it increases their health-enhancing antioxidant content, researchers have discovered.

Published in Frontiers in Plant Science, their study shows that growing grasses alongside blueberry plants corrects signs of iron deficiency, with associated improvements in berry quantity and quality. The effects are comparable to those seen following standard chemical treatment - providing a simpler, safer, cheaper and more sustainable strategy for blueberry farming on sub-optimal soils.

What do superfruits eat?

All soils are rich in iron, but nearly all of it is insoluble.

"Most plants get enough iron by secreting chemicals that make it more soluble," explains senior study author Dr José Covarrubias, Assistant Professor of Agriculture Sciences at the University of Chile. "These iron 'chelators' can be released directly from the roots, or from microbes that grow among them, and allow the iron to be absorbed."

"Blueberries, however, lack these adaptations because they evolved in uncommonly wet, acid conditions which dissolve the iron for them."

As a result, most of the world's relatively dry or alkaline ('limey') cropland is unsuitable for optimal blueberry growth.

"Iron is essential for the formation and function of plant molecules like chlorophyll that allow them to use energy," Covarrubias continues. "That's why iron deficiency shows up as yellowing leaves - and drastically reduces plant growth and yield.

"And in blueberries, iron-dependent enzymes also produce the 'superfruit' antioxidants responsible for their celebrated blue skin and health-enhancing effects."

Strong blueberries must pump iron - but at what cost?

There are two approaches to correcting iron deficiency in blueberries: acidify the soil, or add synthetic iron chelators. Each has its drawbacks, says Covarrubias.

"The commonest industrial approach is soil acidification using sulfur, which is gradually converted by soil bacteria into sulfuric acid. The effects are slow and difficult to adjust - and in waterlogged soils, hydrogen sulfide might accumulate and inhibit root growth.

"Acids can also be added directly via irrigation systems for more rapid acidification - but these are hazardous to farmers, kill beneficial soil microbes, and generate carbon dioxide emissions.

"A commoner strategy among growers is application of iron bound to synthetic chelators - often sold as 'ericaceous fertilizer' - but these are very expensive and leach potentially toxic chemicals into the water table."

A cheaper, safer alternative is needed for efficient large-scale blueberry production. Thankfully, one already exists.

"Grasses - which are well-adapted to poor soils - can provide a sustainable, natural source of iron chelators via their roots when grown alongside fruiting plants. Intercropping with grass species has been shown to improve plant growth and fruit yield in olives, grapes, citrus varieties - and most recently, in blueberries."

A grassroots approach to sustainable blueberry farming

Now, Covarrubias and colleagues have brought intercropping a step closer to the mainstream of blueberry cultivation.

For the first time, they measured the effects of different methods of iron chelation on antioxidant content and other fruit qualities in blueberries.

"In an orchard of 'Emerald' blueberry bushes cultivated in alkaline (pH 8) soil, we compared the effects of five different iron chelation treatments: a 'gold-standard' synthetic iron chelator (Fe-EDDHA), intercropping with grass (common meadow grass or red fescue), cow's blood (Fe-heme), or no treatment (control)."

"We found the association with grasses increased not only the total weight and number of blueberries per plant, but also the concentration of anthocyanins and other antioxidant compounds in their skins, compared to control. The effect sizes were comparable with the proven synthetic chelator Fe-EDDHA, whereas applications of Fe-heme from cow's blood - a fertilizer commonly used in home gardens - had no significant effect."

The beneficial effects paralleled improvement in the plants' iron status (leaf color), which was also comparable between the grass-associated and the Fe-EDDHA-treated plants. None of the treatments had a significant effect on average berry weight

Turf is ready to roll out for healthier blueberries

A potential limitation of intercropping observed in the study was a decrease in berry firmness, since firmer berries are favored by consumers.

"The association with grasses decreased berry firmness compared with control plants, whereas the berries collected from plants treated with Fe-EDDHA reached intermediate values.

"However chemical analysis showed a non-significant trend towards increased ripeness in the berries collected from the intercropped plants, which could account for this small difference."

Intercropped plants also required an additional water supply to maintain a similar soil moisture to other treatments, but plant management was otherwise straightforward and the same across groups. The grasses were kept cropped between 5 and 15cm - a typical range for an attractive mown lawn.

"Our findings validate intercropping with grasses as a simple, effective, sustainable alternative to standard iron correction strategies in blueberries," concludes Covarrubias. "Both commercial and private growers can put this strategy to use right away to boost their blueberry crop and antioxidant content."

###

Please link to the original research article in your reporting: https://www.frontiersin.org/articles/10.3389/fpls.2019.00255/full

Frontiers is an award-winning Open Science platform and leading Open Access scholarly publisher. Our mission is to make research results openly available to the world, thereby accelerating scientific and technological innovation, societal progress and economic growth. We empower scientists with innovative Open Science solutions that radically improve how science is published, evaluated and disseminated to researchers, innovators and the public. Access to research results and data is open, free and customized through Internet Technology, thereby enabling rapid solutions to the critical challenges we face as humanity. For more information, visit http://www.frontiersin.org and follow @FrontiersIn on Twitter.

soil colors
soil colors

Posted on Tuesday, April 2, 2019 at 11:17 AM
Tags: acid (2), alkaline (2), avocado (272), citrus (304), nutrients (20), pH (6), soil (22)

Citrus Thrips Damage Increase?

A local Ojai grower asks why there seems to be more citrus thrips damage to 'Pixie' mandarins this year.  Was it because of the extended bloom due to warmer spring last year?  The hotter summer up there that was more similar to climate in the Central Valley?  Was it due to the Area-Wide Spraying for Asian Citrus Psyllid - ACP?  Or is this a remnant of the Thomas Fire that dumped ash all over the county, disrupting biocontrol agents like lady bird beetles?

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=26095

And what else does fire do to citrus?

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=28315

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=26510

This is classic  thrips damage. In this area, it is not usually a problem.  This year it seems to be more common. It's not always clear what is the main cause of and what all the interactions are that lead up to an outbreak like this.  Just that there is damage now that occurred 10 months ago.

thrips damage pixie
thrips damage pixie

Posted on Thursday, March 28, 2019 at 2:20 PM
Tags: biocontrol (13), citrus (304), citrus thrips (1), mandarin (65)

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