- Author: Ben Faber
There was a lot of odd looking, water-soaked Satsuma fruit showing up this year along the coast. It was showing up as late as March since fruit can hang so much longer along the coast than the Central Valley and hotter areas. It turns out its an abiotic issue and is more associated with the cooler, coastal environment. Recently a "Gold Nugget" mandarin came in that had a very similar look to the rind. This variety doesn't have immediate satsuma parentage, but who knows what is in its past. The disorder is most commonly associated with cool, foggy or rainy conditions. In the fall we had those conditions and maybe that's what set it off. Later, secondary fungi move in to colonize, the depressions that first occur.
- Author: Ben Faber
Recently, I read an article in "Fresh Plaza" about the arrival of large amounts of 'Kinnow' mandarin fruit from Pakistan. http://www.freshplaza.com/article/117470/Discover-Pakistani-kinnow-mandarins-at-Fruit-Logistica-2014#SlideFrame_1
This is a country that is surrounded by countries with huanglongbing. It's also the country where Mark Hoddle, Biocontrol Specialist from UC Riverside, collected Tamarixia radiata , the tiny wasp that is helping control Asian Citrus Psyllid. Pakistan has invested heavily in juice plants just for this industry which was established with this selection that came out of the Citrus Research Station breeding program in the 1930's. It makes me wonder if there might be a significant tolerance to this citrus disease in this mandarin variety. There has been a lot of work by both USDA and U. of Florida evaluating citrus varieties for tolerance to HLB. A wide range of tolerances have been noted. Fred Gmitter along with others are involved with this work and find that under different climatic conditions, resistance can vary. In the 'Kinnow' variety, it looks like there is hope in finding a variety that can be used to breed tolerance into other varieties. The fruit itself is noted for its juiciness and sweetness. But as you can see from the photo, it's got a lot of seeds.
- Author: Ben Faber
UC Riverside and the Citrus Research Board partner to provide:
UC Riverside Citrus Day for Professional Industry members
Thursday, February 20, 2014
8 a.m. to 3:00 p.m.
UCR Agricultural Operations, Riverside, California
For information: (951) 827-5906
Please join us for the 3rd Annual Citrus field day designed for citrus growers and citrus industry representatives. Pending approval, we will be offering 2.5 hours of California Continuing Education
Credit for Pest Control Advisers (PCA).
Presentations, field tours and topics of interest:
Pesticide safety – Vince Samons
Update on ACP and HLB in California – Joseph Morse
Phytophthora diseases of citrus – Jim Adaskaveg
Lemon Varieties for the Desert –Glenn Wright
Understanding factors that influence the eating experience in citrus – David Obenland and Mary Lu Arpaia
Citrus Variety Collection tours of new cultivars and “unforbidden” fruits – Tracy Kahn, David Karp, Tom Shea, and Robert Krueger
Update on Citrus Rootstock Field Demonstration – Mikeal Roose
Barbeque Lunch included.
Registration: $18. Deadline: February 14, 2014. There will be no walk-in registrations. We will email directions and updates to all who have registered.
Space is limited so please register early.
Please register online at
http://form.jotformpro.com/form/40196914861965
To make a tax-deductible contribution to the
Citrus Variety Collection Endowment fund or the Citrus Research Center & Agricultural Experiment Station support fund go to the following link and select College of Natural and Agricultural Sciences then select the specific fund:
https://advancementservices.ucr.edu/GivingForm.aspx
- Author: Ben Faber
'Bitters', 'Carpenter' and 'Furr' trifoliate hybrids are three new citrus rootstocks released in August 2009 by the University of California Riverside. These three rootstocks are hybrids of Sunki mandarin x Swingle trifoliate orange. As rootstocks for citrus, they produce good quality fruit on small ('Bitters') or medium-large ('Carpenter' and 'Furr') trees. They all show good tolerance to Citrus tristeza virus (CTV), but vary in their tolerance of Phytophthora and nematodes. They all produce uniform seedlings due to high levels of nucellar embryony, and are graft compatible with sweet orange, Lisbon lemon and grapefruit. They also appear compatible with mandarins based on observation of 11 year-old satsuma and ‘Pixie’ trees. We are comparing their performance compared to ‘C-35’ as a standard and with ‘sour orange’. These are being grown with ‘Pixie’ and ‘Lisbon’ lemon scions. Sour orange grows well on calcareous, heavy soils and are less prone to nematodes. It turns out that mandarin and lemon are not prone to tristeza virus when grown on sour orange rootstock. Trees will be planted this coming spring. Stay tuned.
- Author: Carol J Lovatt
- Author: Elizabeth J Fichtner
Alternate bearing is typically initiated by adverse climate. Once initiated, in the absence of additional environmental constraints affecting crop load, the bearing status of an orchard alternates between ON and OFF years, with ON years exhibiting less vegetative growth than OFF years. This biennial cycle, however, can be reset by adverse environmental conditions affecting bloom and fruit set. Adverse conditions 8-10 weeks prior to bloom may cause abortion of female flower parts, resulting in a high proportion of staminate (male) flowers that do not give rise to fruit. Additionally, adverse weather conditions at bloom may impact pollination and subsequent fruit set. Any conditions resulting in loss of crop during an anticipated ON year may render the season an OFF year.
For a fuller discussion of this topic, see the full article by Carol Lovatt at:
http://ceventura.ucanr.edu/newsletters/Topics_in_Subtropics45348.pdf
The Topics in Subtropics Newsletter