Posts Tagged: lemon
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
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:
We have had resurgence of broad mite damage on coastal lemons this year. We haven't seen damage like this in a long time. Chlorpyriphos should care of it, but with small orchards, spray drift can be an issue. We looked at releasing the predatoiry mite Neoseiulus californicus. In the lab we challenged broad mite successfully so we took it out to the field. This is not the best time to release, because of the cold weather. Also it's best to release into a rising pest pressure. When there are too many pest mites, it's difficult to get good control. We released at an economic level of about 100 per tree, whihch would cost about $150 per acre. We've counted for 5 weeks and there is little apparent control in the field. ikt's just been too cold to build the population of beneficials. We'll try again next spring if the broad miter is there.
Curlling leaves from mite damage and the small mites hiding in fruit depressions
You see the darndest things in orchards, aside from all the junk that people throw out of their cars. Here's a case where someone had a little time on their hands and tattooed some fruit in the field. Apparently it was some pointed object that scared the skin and then it healed over. Maybe this is a new marketing opportunity for Meyer lemons.
photo by S. Caughey
Biochar is a partially burned organic matter that can be used as a soil amendment. Its use was identified in the Amazon jungles where the terra preta (black earth) was first identified in areas where humans had incorporated the charcoal and improved plant growth was noted. There is a growing industry world-wide to take organic matter and create biochar because of potential environmental benefits, such as reduced greenhouse gas emissions, improved soil fertility, reduced leaching of nutrients and chemicals from plant root zones, and water retention. Biochar could potentially last for hundreds of years once incorporated in the soil. There have been many claims for biochar, but so far there is not a lot of scientific basis for these claims. One of the results recently has been the standardization and testing methods for biochar, so the material can be better characterized and studies can be standardized. The guidelines can be found at this link: http://www.biochar-international.org/sites/default/files/Guidelines_for_Biochar_That_Is_Used_in_Soil_Final.pdf
Biochar has been most notable in soils that are of poor quality which are characteristic of highly leached soils found in the Amazon. The question is can biochar perform in the relatively young soils of California where irrigation and nutrients are better controlled. We are doing a quick and dirty little trial on avocado and citrus to evaluate plant performance in rocky soils, calcareous soils and with trees that are doing “poorly”. If we see some indication that there is something working, we will expand the study with more rigor and more situations.
Photo of Terra Preta from Cornell University's College of Agriculture and Life Sciences
Travel can be enlightening. In Turkey I learned that sour orange rootstock is routinely used with lemon and mandarin scions without any fear of tristeza virus, a formidable disease of oranges. When I heard this I asked Georgios Vidalakis in charge of the UC Clonal Protection Program and a virologist. And he said that it was true and the neat thing is that the rootstock can handle heavy, calcareous soils better than other citrus rootstocks. So we are doing a trial on rootstocks and sour orange is included.
Something else I “learned” was that if you girdle citrus at flowering, the fruit has few or no seeds. Well, I talked to many growers and scientists and they all said the same thing. I went through the citrus literature and I could find no mention of this. I emailed Carol Lovatt, the plant physiologist at UCR and she said that when you alter hormone flows by girdling, who knows what might happen. So we set up a little trial in lemon that flowers pretty much all year long on the coast. Every month we girdle branches with either a hand saw or a girdling knife which make different sized cuts, flagging the branches with different colored tape to identify the girdling date. Over an 18 month period we harvested fruit and cut it to count seeds. And………………………………………there was only a slight difference in seed numbers, a few less in the girdled trees.
The goal of this trial was to see if girdling worked and if so, what was being changed in the tree and if could identify that, then maybe we could develop a nutritional program that would do the same thing. That way we wouldn’t need to girdle. But not everything you hear turns out to be true.