Evolutionary ecology of climacteric
and non-climacteric fruits
Published:15 September 2021https://doi.org/10.1098/rsbl.2021.0352
Fleshy fruits can be divided between climacteric (CL, showing a typical rise in respiration and ethylene production with ripening after harvest) and non-climacteric (NC, showing no rise). However, despite the importance of the CL/NC traits in horticulture and the fruit industry, the evolutionary significance of the distinction remains untested. In this study, we tested the hypothesis that NC fruits, which ripen only on the plant, are adapted to tree dispersers (feeding in the tree), and CL fruits, which ripen after falling from the plant, are adapted to ground dispersers. A literature review of 276 reports of 80 edible fruits found a strong correlation between CL/NC traits and the type of seed disperser: fruits dispersed by tree dispersers are more likely to be NC, and those dispersed by ground dispersers are more likely to be CL. NC fruits are more likely to have red–black skin and smaller seeds (preferred by birds), and CL fruits to have green–brownish skin and larger seeds (preferred by large mammals). These results suggest that the CL/NC traits have an important but overlooked seed dispersal function, and CL fruits may have an adaptive advantage in reducing ineffective frugivory by tree dispersers by falling before ripening.
- Author: Petr Kosina
New online course on diagnosing herbicide injury now available
—Petr Kosina, UC Statewide IPM Program
A brand-new online course on Diagnosing Herbicide Injury focusing on how an herbicide injury situation can arise, what information can help diagnose symptoms during field investigations, and what tools are available to you, is now available from the UC Statewide Integrated Pest Management program (UC IPM).
When unexplained damage is noticed on a crop or other non-weed plant, herbicides are often a primary suspect. That is no surprise because herbicides are very powerful and effective tools used to control weedy plants in a wide variety of locations. However, symptoms of many other plant stresses, such as diseases and nutrient deficiencies or toxicities, can closely resemble the injury symptoms caused by herbicides. Economic implications of herbicide damage can vary–in some cases visible injury may have very little direct economic effect while in others, even slight herbicide symptoms can affect the marketability of affected plants. In addition, the presence of an unregistered herbicide on non-target crops can result in illegal residues which could have both safety and legal consequences.
The new online course was developed by Dr. Brad Hanson and Dr. Kassim Al-Khatib from the Department of Plant Sciences at UC Davis, and UC IPM instructional designers. If you are a grower, pest control adviser, or pesticide applicator, then this course is a great opportunity to learn about how to approach crop injury investigation when herbicide is suspected cause. You will learn how herbicides injure plants, how long herbicide symptoms may last and factors that may influence the time that herbicide injury symptoms are visible, possible scenarios of herbicide exposure based on uniform and variable injury patterns observed in the field, how to prepare samples for the laboratory analysis and more.
The course content is free to anyone who wishes to view it. For those requiring a certificate of completion and continuing education units (CEUs), the regular cost is $30, but we are offering a reduced price of $15 through October 31, 2021. Diagnosing Herbicide Injury course has been approved by the California Department of Pesticide Regulation (DPR) for 1.5 continuing education units (CEU) of Other, Certified Crop Advisor (CCA) for 1.5 units (IPM), and the Arizona Department of Agriculture for 1.0 Credit.
If you are a DPR license or certificate holder with a last name beginning with letters M through Z, then this will be your year to renew. Now is a good time to check out the other UC IPM online training courses offered. All are 50% off the regular price through October 31st. DPR strongly suggests returning renewal packets back to them by October so that your license or certificate can be renewed before it expires. Many of our courses are accredited by DPR for continuing education hours and also by the California Structural Pest Control Board (SPCB), Certified Crop Advisor (CCA), the Western Chapter of the International Society of Arboriculture (WCISA), and the Arizona Department of Agriculture.
Pruning trees is dangerous. You think you know which way that branch is going to drop, and instead it falls right on your head. Good thing you are wearing a helmet, but a big limb is not going to be stopped by a helmet. A recent report out of Penn State developed some statistics on tree “felling' – pruning – which should be noted by anyone cutting trees. https://onlinelibrary.wiley.com/doi/10.1002/ajim.23286 . Where it reads “logging and landscaping”, read avocado pruning. These statistics are just for deaths from trees, not injuries. I couldn't find on-farm statistics of pruning injuries, but, know that farming is one of those high risk activities like other tree-related interactions.
Tree felling — whether by professional loggers in a forest setting or by landscapers in urban and rural landscapes — is the most dangerous job in what are two of the most dangerous industries, according to Penn State researchers who conducted a new study of associated deaths.
The Occupational Safety and Health Administration calls logging “the most dangerous occupation in the United States.” The fatal injury rate for loggers is more than 30 times the rate for all U.S. workers. Tree-care workers also encounter hazards at rates much higher than the average employee.
“This was the first research to look at commercial logging and landscaping services together,” said Judd Michael, Nationwide Insurance Professor of Agricultural Safety and Health and professor of agricultural and biological engineering, College of Agricultural Sciences. “It was a unique and more accurate way to assess fatalities. The commonality, of course, is that workers in both fields fell trees. They do it using very different methods, but either way, it is extremely hazardous work.”
Logging in Appalachia and other regions with forests growing on rough, mountainous terrain continues largely unmechanized, with workers felling trees with chainsaws, standing at their bases; landscapers, on the other hand — because they must control the fall of limbs and trunks — must climb trees with chainsaws and cut sections down.
To reach their conclusions, the researchers analyzed an Occupational Safety and Health Administration database to identify occupational tree-felling fatalities in the United States during a 10-year period — from 2010 through the first half of 2020. They compared data for the two industry segments of logging and landscaping services.
In findings recently published in the American Journal of Industrial Medicine, the researchers reported that there were 314 fatalities over the period. The victims were overwhelmingly male, with the median age being 43. “Struck-by” was the No. 1 event type causing fatalities, with the head being the most frequent body part involved in fatalities.
Falls from elevation was the only event type significantly different between the logging and landscaping industries, Michael noted, adding “but you would expect that, given the nature of the work.” Poor decision-making was listed as a key component of fatal incidents, and in some cases bystanders were fatally injured due to the actions of others.
The number of tree-felling fatalities varied greatly from year to year during the study, and there were no clear trends in fatality rates, Michael pointed out. The reasons for the cyclical rise and fall of tree-felling fatalities are unknown but he suspects they may be driven by weather events. One possible causal factor was whether hurricanes made landfall in the coastal states.
Storm damage may lead to increased fatalities, he explained. Years such as 2012, 2017 and 2018 with abnormally high damage costs from Atlantic storms also saw relatively high numbers of landscaping fatalities that could be associated with storm‐damaged urban trees, while 2014 and 2015 had very quiet hurricane seasons and relatively few fatalities.
“Look at what happened with Hurricane Ida recently, with all the power lines that were down because of downed trees in Louisiana,” he said. “We don't know yet if that will lead to landscape tree-feller deaths, but we suspect large storms lead to more fatalities. Utilities can't restore power without clearing downed trees, so the importance of keeping tree operations safe can't be overstated.”
Getting a better handle on fatality numbers is just an early step in trying to make the job of tree fellers safer, Michael explained. And it is not as simple as just advising that protective equipment should be worn.
“Personal protective equipment is mandated, but that means a hard hat or some chaps on a worker's legs to stop a saw from cutting through,” he said. “But if you have a 1,000-pound limb falling from 10 feet or 50 feet, no equipment is going to protect them. And that's one of our key takeaways — you can have all the protection you want, but it won't help you if you get hit by a tree trunk or large limb. That's why we need to have better decision-making to keep people out of danger.”
There is a need to focus on hazards associated with tree-felling activities so that proactive prevention strategies can be developed, Michael suggested.
“Employers in the landscaping industry should put extra emphasis on fall protection and prevention for those working in elevated positions,” he said. “Greater attention to falling object avoidance for persons working around a tree being felled could also prevent fatalities. Logging companies should strive to adopt mechanized methods for tree felling.”
But fatalities from tree felling are just a fraction of the number of severe injuries incurred while working around trees, Michael added. By focusing on the cause of fatalities, Penn State researchers hope that strategies can be developed to also reduce the number of injuries in these important industries.
More Information on safely working trees:
And KEEP those TOOLS SHARP: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=28916
Santa Barbara County Coastal Gardener
This garden column provides information on home, garden and landscape problems. It was created by Frank Laemmlen Ph.D., Farm Advisor Emeritus in the Santa Barbara County Cooperative Extension Office.
The original column was in question and answer format with 1 or more questions answered in each issue. We have separated each topic and have listed them as fact sheets.
- Can You Rent a Christmas Tree
- Carpet Beetle
- Cloths Moth
- Drugstore Beetle
- Fungus Gnat
- Little Black Ant
- Oak Bark Beetle in the Home
- Patio Plants
- Sap on Table
- Spots on Rubber Plant
- Take care of Your Skin
- Attracting Hummingbirds
- Broadleaved Weed Control in Lawns
- Controlling Oxalis by Replanting
- Controlling Earthworms
- Crude Oil
- Deer Resistant-Tolerant Plants
- Fertilizing Sandy Soil
- Iron Chlorosis
- Lawn Causing Itching and Welts
- Lawn Fertilization and Watering
- Lawn Mowing Heights
- Lawn vs Tree
- Leaf Scorch on Japanese Maple
- Lillies Poisonous to Cats
- Living With Oaks
- Mosses, Alga and Slime Molds
- Mushrooms in Lawns
- Niger Seed in Bird Feed
- Poison Oak
- Propagating Willows
- Pruning Roses and Fruit Trees
- Pruning Trees to Speed Growth
- Queen Palm Problems
- Railroad Ties
- Sparse Foliage and Large Seed Crops on Birch
- Sucker Growth on Roses
- Tip Dieback on Dogwood
- Trees Made Stronger by Bending in the Wind
- Yellow Lawns
Vegetables and Fruit
- Avocado Nutrient Deficiency
- Avocado Fruit Set
- Chilling Hours
- Citrus Fruit Cracking
- Compacted Soil
- Compost and Composting
- Eucalyptus Mulch
- Fertilizing Fruit Trees
- Fertilizing Potted Plants
- Fireplace Ash
- Fruit Splitting
- Growing Avocado from Seed
- Growing a Pineapple from the Top
- Harvesting Avocados
- Harvesting Pears
- Harvesting Potatoes
- Medium for Planter Boxes
- Nectarine Problems
- Planting Trees
- Planting Vegetables
- Pollinating Squash
- Poor Seed Germination
- Pruning Avocados
- Pruning Roses and Fruit Trees
- Rehabilitation of Freeze Damaged Plants
- Root Sprouts
- Stop Olives from Bearing
- Tomato Fruit Set
- Tomato Leaves Turning Yellow
- Tomato Problems
- Walnuts Shriveled and Inedible
- Will Bird Damaged Fruit Cause West Nile Disease
- Author: Rebecca Ozeran
In the 5 years I've been with UCCE, I have received a few recurring weed-related questions. I've certainly had some unique requests, like how to deal with fig trees invading a livestock water pipeline, or whether filaree might be harmful to guinea pigs (it isn't). But often, questions I receive about rangeland or pasture weeds fit under three categories:
- Is this plant toxic to my animals?
- How can I get rid of yellow starthistle?
- What can I plant in my pasture to outcompete all these weeds?
Of course, each question has its own “It depends”-style answer. But today, I want to share the resources I recommend for these Frequently Asked Questions.
Is this plant toxic? (Usually following the question, “What is this plant?”)
- Toxicity varies with plant species, growth stage, part or structure (e.g leaf versus flower) and relative abundance. Toxicity also varies with animal species and size, and what other feed is available. Some plants are toxic at all growth stages and in all parts of the plant (such as oleander) while other plants accumulate toxins at certain times of their growth cycle (such as plants that accumulate nitrate) or affect livestock species differently (such as yellow starthistle).
Fiddleneck, like oleander, accumulates toxins in all plant parts, though the concentration can vary. Fiddleneck seeds and flowers often contain the highest concentrations of alkaloids within a single plant.
- Fortunately, we have an excellent guide that describes common toxic plants and how to reduce risk to your animals: Livestock-Poisoning Plants of California. For plants that aren't listed, you can always contact your local farm advisor for assistance in plant identification and management! If you suspect plants are poisoning your animals, please contact your veterinarian ASAP.
How can I get rid of yellow starthistle?
- While we probably can't eliminate it completely,yellowstarthistle can be managed to reduce its impact on landscapes and livestock. Several usefulresourcesdescribeyellowstarthistle management, and can be freely accessed or downloaded:
- UC IPM Pest Note on Yellow Starthistle, a brief overview of the plant itself and key management strategies
- Yellow Starthistle Management Guide, published through Cal-IPC, probably the most thorough document on yellow starthistle impacts and management tools
- Yellow Starthistle weed report, from Weed Control in Natural Areas in the Western United States, especially handy if you want a concise comparison of management options, or something that is well formatted for printing out
What do I plant to manage pasture weeds?
- Maintaining healthy forage cover is one of the best ways to reduce weed pressure in a grazing or haying area, whether irrigated or not. However, getting good forage established can be more challenging when there are weeds already present. Drought years like this year don't help, either – many deep-rooted broadleaf weeds are doing fine while desirable grasses had a shorter than usual growing season. And, of course, site-specific variations affect what forage plants might be competitive, and what weeds they might have to outcompete.
- Because the answer is more complicated than “buy X seed mix”, I usually refer to the excellent guide, Establishing and Maintaining Irrigated Pasture for Horses. The principles of pasture preparation, including strategies for weed management during pasture establishment, are similar across grazing livestock species. Most of the information in the guide can also apply to dry pastures aside from the specific sections about planning and using irrigation.
Healthy pastures will better outcompete weeds. The species in that pasture will vary across the state. Having sufficient moisture - from rain or irrigation - also impacts weediness!
Now, range and pasture weed questions aren't going to be completely resolved by a single blog post – but I do hope this post is a helpful starting point for anyone who manages rangelands or pastures.
If you have a question that isn't listed in this short FAQ, feel free to reach out! I'm happy to expand this resource. You can comment on this blog, email firstname.lastname@example.org, or message through my program Facebook page.