Posts Tagged: citrus
Tuning up for Pruning Up--Care, Maintenance and Utilization of Hand Pruning Tools
University of California
Fall is passing into winter and the bare sticks in my deciduous fruit orchard are calling me to my annual fruit tree pruning chores. I can prune my entire orchard with very few tools: a good pair of bypass clippers, a similar set of loppers (optional) and a high quality “razor” or “tri edge” saw. Most tools require some maintenance especially the clippers and loppers. Sharpening is the usual need. Clippers are easily sharpened but modern saw blades can not be sharpened by gardeners and should be replaced. Sometimes it is just as easy to buy a new saw, replacing the old one when blade eventually dulls or is bent from over zealous use (illustration 1)
Illustration 1: Tri-edge saw blades are made from stainless steel and are not easily sharpened. When dull or bent they should be replaced
Before using your pruning tools inspect them for signs of damage. Blades should be sharp and unbent. Loppers should have their rubber “bumpers” intact otherwise your knuckles will be smashed after exerting force on a difficult branch. Sharp tools offer less resistance and actually decrease injury to users. One exception here is with the modern “tri-edge” or “razor” saws. These saws can cut so quickly that you may pass through the branch you are cutting and continue on to some part of your anatomy quickly ripping your flesh. I have suffered more cuts (some serious) from these saws than from any other gardening activity. They should be used with careful precision, not with the wild abandon and pruning fervor of the craven academic desperate for real world gardening experience. A thick long sleeved shirt and gloves will also help prevent cuts from hand pruning equipment.
Bypass clippers are so termed because the blade passes by the hook. To sharpen these, find the bevel on the edge of the clippers and align a small file to the same angle of this bevel, and file the bevel until you can feel the sharpness with your finger (Illustration 2). Never sharpen the back side of the bevel—this will create a gap, and every time you cut, a flap of tissue will remain. Back bevel sharpened clippers will require blade replacement or grinding until the back bevel is gone. The hook does not require sharpening, do not attempt to file it. Repeat this process with lopper blades.
Illustration 2: To sharpen bypass clipper blades follow the angle of the bevel. Do not sharpen the flat side of the blade
When you are done pruning for the day, wipe the blades of your clippers and loppers with an oil soaked rag or apply a few drops of oil and rub it into the blade. Most modern saws blades are made from stainless steel and require no oil protection.
As a Cooperative Extension Advisor, one of the most common questions I receive is: “Should I sanitize my clippers between cuts or between uses on various plants?”. Indeed, many publications, extension leaflets, gardening columns, and other sources make broad recommendations to sanitize clippers after every cut. Some articles even compare various products for their killing efficacy. Often blind recommendations are made to sanitize clippers when the pathogen is not even known or specified. It is not necessary to sanitize your clippers when pruning most garden plants and fruit trees. There are a few pathogens that are spread by dirty pruning equipment but published evidence that they are spread by hand pruning equipment (especially clippers) is nil. One exception is palm wilt caused by Fusarium oxysporum f.sp. canariensis which is easily spread by saws. Some of the canker fungi caused by Botryosphaeria can also be spread by pruning equipment. With many of these pathogens, a wound is required for infection so it may not be that the clippers are spreading disease so much as providing an entry point (infection court) so that pathogens have a way to enter.
In my garden, I have never, and will never need to sanitize clippers between cuts. However, conditions vary across the US, and in some places rain, humidity, and temperature are more favorable for disease development. To avoid spreading pathogens, prune during the dormant season, when the likelihood of pathogen activity is lowest. Apply dormant sprays containing copper to limit the onset of new fungal diseases that may enter pruning wounds. If you still feel you need to protect wounds from dirty clippers I like to use the flame from a plumber's torch to sanitize. A few seconds along the cutting edge front and back kills all pathogens (Illustration 3). Similar for a saw but efficacy is increased if the saw gullets are wiped clean with a cloth and then the flame applied. The only time I take these measures is when I know I am working with plants that can be inoculated with pathogens by pruning (which is rare).
Illustration 3: A plumber's torch will rapidly sanitize saws and blades when pathogens are present in plant tissues.
When pruning garden plants, there are a plethora of recommendations on how to make cuts. Rose experts have extolled the virtues of an angled cut so water runs away quickly, flush cuts used to be recommended by arborists as the highest quality cut. These examples are without research foundation. Cuts on woody plants should be angled to produce a circular exposure that is the smallest surface area possible. We abandoned flush cuts many years back because they cut into protective zones that limit decay in trees. Some gardeners feel compelled to cover their cuts with a pruning paint and there is a similar paucity of research to support this practice. Leave pruning wounds unpainted.
WESTMINSTER, Colorado - November 23, 2018 - Herbicides have been instrumental in managing Italian ryegrass, a weed that frequently competes with perennial crops in California. Herbicide-resistant populations have become increasingly commonplace, though, including paraquat-resistant Italian ryegrass found recently in a California prune orchard.
A team of scientists set out to determine if the paraquat-resistant population might also be resistant to other postemergence herbicides. Seven other herbicides commonly used in fruit tree and nut tree crops were included in the study, including clethodim, fluazifop-P-butyl, glufosinate, glyphosate, pyroxsulam, rimsulfuron and sethoxydim.
Researchers found the paraquat-resistant population was also resistant to both clethodim and glyphosate. Among the remaining herbicides, glufosinate, rimsulfuron and sethoxydim were found to deliver the best postemergence control. Unfortunately, though, other populations of Italian ryegrass have developed resistance to the three herbicides, indicating their effectiveness may be short-lived.
"Overreliance on postemergence herbicides from a variety of chemical classes can result in weed populations that exhibit multiple resistances," says Caio Augusto Brunharo, a postdoctoral research fellow at the University of California, Davis. "Effective herbicide-resistance management programs are necessary for sustainable weed control."
The researchers recommended a number of preemergence herbicides as control options for Italian ryegrass in fruit and nut tree crops, including tank mixes containing indaziflam and flumioxazin.
Full text of the article, "Multiple Herbicide-Resistant Italian Ryegrass (Lolium multiflorum) in California Perennial Crops: Characterization, Mechanism of Resistance and Chemical Management" is now available in Weed Science Volume 66, Issue 6.
About Weed Science
Weed Science is a journal of the Weed Science Society of America, a nonprofit scientific society focused on weeds and their impact on the environment. The publication presents peer-reviewed original research related to all aspects of weed science, including the biology, ecology, physiology, management and control of weeds. To learn more, visit http://www.
italaian ryefrass resistance
UC Ag Expert talks about
Date: January 23, 2019
Time: 3:00 PM - 4:00 PM
Contact: Petr Kosina email@example.com
Sponsor: UC Ag Experts Talk
Register in advance for webinar at:
Participants of this webinar will receive 1 hour of 'Other' CE units
Note: This webinar has no fee.
Dr. Beth Grafton-Cardwell, citrus IPM specialist and research entomologist, will discuss the lifecycle, damage to citrus, monitoring, methods of control and export issues associated with Fuller rose beetle. Participants can use the chat function of the webinar to ask questions.
fuller rose beetle
Ground squirrels eat a variety of fresh greens as well as seeds and dried nuts. In spring, ground squirrels prefer greens over seeds and nuts. Once the natural grasses begin to dry and wither, squirrels will actively forage for seeds.
As foragers, squirrels are well-adapted to find sparsely dispersed food, one seed at a time. Once squirrels have had their fill, they will
collect food in their cheek pouches and take it back to the nest to form a cache for later use. Squirrels tend to forage close to their burrow, although they will travel for desirable foods.
How Biology relates to control:
The California ground squirrel prefers to forage for food in the early morning or late afternoon/early evening to avoid the day's heat. In some crop situations, especially nut crops, squirrels may prefer the crop to the point where they will not eat any bait. If the squirrel won't eat the bait, the poison bait method will not work. In this case, an alternative control approach may be necessary (trapping or fumigation).
Understanding these feeding preferences is extremely important when using baits since they are seed based. Also, in irrigated crops or landscape areas, squirrel feeding preferences are influenced by what food is available. For example, the natural vegetation may be dry in early summer and squirrels are actively foraging for seed. If newly sprouted crops are available however, the squirrels may take them with great delight.
The calendar of ground squirrel diet, activity and control measures is adapted from the Best Management Practices for Ground Squirrel Control website http://ipm.ucanr.edu/PMG/PESTNOTES/pn7438.html. Calendar dates are merely an estimation of time; actual time frames may vary according to the weather and location.
Ground squirrels - Spenrophilus sp. of which there are 17 species may cause damage to avocado orchards by eating fruit, branches, and making burrows near or under trees which expose roots and redirect irrigation water. The most common ground squirrel is the California or Beechey ground squirrel Spermophilus beecheyi.
*An adult will weigh from 1 to 2 ½ pounds and is tan in color with flecked or mottled fur.
*Females produce one litter each year, averaging six to eight offspring.
*They are active in the daytime.
*Their diet may consist of green herbage in winter and spring and seeds during the summer and fall.
*They hibernate during cold winters, but are active year-round in avocado growing areas
*Ground squirrels are not repelled by any chemical or physical means. Thus, control through the use of toxic fumigants, poison baits, traps, or shooting is the only effective control measures available
*They are also preyed on by eagles, raccoons, foxes, badgers, weasels, rattlesnakes and clever dogs
more on those cute animals:
While conducting surveys across Merced County, I have noticed diverse ways growers secure the ends of irrigation tubing. Many are attached using some type of stake made of wood or PVC in which the tubing is tied. Other orchards have the lines wrapped around a tree and used as an anchor for the line. Finally, some of them are staked directly into the ground.
Irrigation tubing moves because of expansion and contraction of the plastic caused by temperature changes, as well as, from the water and air moving through the irrigation system. Securing the tubing creates tension that helps prevent the tubing from moving. These keeps the emitters and microsprinkers in place which helps maintain good irrigation efficiency.
There are a few problems with securing the tubes. The first is the added cost and time to first secure the tubing and then maintain how the tubing was secured. Secondly, the lines may contract after fixing, which can pull them off the riser. Finally, the lines, if wrapped too tight, can cut into and girdle the tree. All of these are preventable.
If you do choose to secure the end of your irrigation tubing, below are some considerations to take into account:
- Leave some slack in the tubing: Due to changes in temperature, plastic tubing expands and contracts. When tightly secured tubing contracts, coupling points may become undone (e.g., at the riser) or may cause the plastic in the tubing to stretch, creating weak points that may eventually break.
- Be wary of using trees to secure tubing: While this may cut down on supply costs, make sure it does not begin to girdle the tree.
- Do it right: Since you are taking the time (and money) to secure your tubing, be sure to do it right. There is a lot of power in the contraction and expansion of irrigation tubing, and a poorly installed system will eventually fail.
- Secure irrigation tubing in the winter: Securing tubing on colder days prevents problems related to contraction. Cold tubing that does not have enough slack will just expand and create the slack that was needed. Hot tubing that does not have enough slack will contract and cause problems, as described above
Whether or not you decide to secure your irrigation tubing is up to you. Ultimately, the end goal is a well-irrigated field. Securing irrigation tubing, if done right, is just one thing to help accomplish that goal.
From the Almond Doctor: https://ucanr.edu/sites/sayalmond/The_Almond_Doctor/