- Author: Ben Faber
I recently came across a library of all kinds of images of pests, diseases and crops. It has lots of entries, such as “Bees of the United States”:
https://www.ipmimages.org/browse/projectsubject.cfm?proj=1154
Alkali bee
And images of citrus pests and diseases and even different cultivars of citrus, under “Citrus ID”:
https://www.ipmimages.org/browse/projectsubject.cfm?proj=108
'Xie Shan" citrus cultivar
And even a few avocado images:
https://www.ipmimages.org/browse/Areathumb.cfm?area=277
But there's a heck of a lot more.
Clicking on the different links and their volumes of images will take some time because of the shear number. The images have been collected as a public data base for not only academics, but also for the general public. At present, it's not too easy to search, but it's worth a look.
Here's a list of the different categories that can be perused:
Commodity Groups
Grain Sorghum and Small Grains
Grain Sorghum and Small Grains
Plant Pathogen and Microbe Culture Images
Forestry, Wildlife and Natural Resources
Taxonomy
Biological Controls
Damage Types
Insects
Bark Beetles and Phloem Feeders
Seed, Cone, Flower, Bud and Fruit Damaging Insects
Diseases
Parasitic and Epiphytic Plants
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- Author: Ben Faber
Plant-out-of-place photo galleries:
http://wric.ucdavis.edu/photo_gallery/photo_gallery.htm
http://ipm.ucanr.edu/PMG/weeds_intro.html
Horseweed - Conyza canadensis
Herbicide treatment table for citrus:
http://ipm.ucanr.edu/PMG/r107700411.html
And if you are wondering what herbicide damage might look like on various plant species (this is heavily weighted to annuals and landscape plants):
http://herbicidesymptoms.ipm.ucanr.edu/index.cfm
Blueberry herbicide damage
- Author: Pam Kan-Rice
Roof rats are running rampant in California orchards this year, according to UC Agriculture and Natural Resources scientists.
“In pistachio and other nut orchards, roof rats are burrowing and nesting in the ground where they're chewing on irrigation lines, causing extensive damage,” said Rachael Long, UC Cooperative Extension advisor. “They are also nesting in citrus trees, feeding on the fruit and terrifying field workers when they jump out as people are picking fruit. The chewing pests are also girdling citrus limbs, causing branch dieback.”
The wet winter of 2017 led to lots of weed seeds for rats to eat. “Last season, rats were also nibbling on pomegranates, avocados, and other fruit and nut crops, rendering them unmarketable,” Long said.
Holes in the ground around the base of pistachio trees throughout a Yolo County orchard puzzled the grower.
“We looked for ground squirrels, but never saw any,” Long said. “We set up game cameras, but only got birds and rabbits. We put rodent bait in the holes, but the digging didn't stop.”
Long, the pest detective, cracked the case by consulting Niamh Quinn, UC Cooperative Extension human-wildlife interactions advisor based in Irvine. “She informed us that the damage we were seeing was from roof rats.”
Burrowing roof rats sounds like an oxymoron. While roof rats generally don't burrow in urban environments, their country cousins have been known to burrow.
“It's not true that they don't burrow,” Quinn said. “When I worked as staff research associate for Roger Baldwin, UC Cooperative Extension wildlife specialist, that is mostly what we studied, burrowing roof rats in orchards.”
Control measures
Baldwin said, “It seems to be a good year for rats in a number of different areas and crops throughout the state. I've received more questions and comments about rats this year than perhaps the last 10 years combined. As for bait application, putting bait down burrow systems for rats doesn't usually work too well, so I'm not surprised that approach didn't work. Growers will likely have better luck with bait stations in the trees.”
Because the rats climb, Baldwin suggests attaching bait stations to tree branches.
“In addition, elevating the bait stations will eliminate access to bait for many protected mammal species, such as kangaroo rats,” Long said. “The bait diphacinone grain can be purchased from some ag commissioners' offices. This is what Roger Baldwin said they tested and it worked.”
As for the bait stations, they should be designed so that there isn't any spillage for nontarget animals to eat, Long said.
When roof rat outbreaks occur, rodenticides are often needed to prevent crop damage. However, timing is critical as diphacinone use is highly restrictive and not allowed during the growing season, which is beginning as the weather warms.
“Check the product label for application instructions,” Long reminds growers. “It's the law.”
Identifying the pest
One way for growers to identify whether they have roof rats is by the size of the burrows. The nocturnal pests are active above ground in trees and below ground.
“Roof rats can forage away from their nest, so you won't likely find signs of their activity, such as rat droppings outside their burrow, to help identify them,” Long said.
Ground squirrels are active during the day, so they are more likely to be seen, dig holes about 4 inches in diameter and forage above ground near their burrows. Vole and mouse holes are 1- to 2-inches in diameter. Roof rat holes are typically 3 to 4 inches in diameter and might have nut shells in front of them, for example pistachio or almond shells. Rabbits will feed on seedling crops, but do not dig burrows.
Roof rats are prolific breeders that reproduce year-round, according to Baldwin. Females typically have three to five litters per year with five to eight young, enabling their populations to rapidly increase. The omnivores feed on a wide variety of plant and animal materials, allowing them to adapt to any environment, including urban and agricultural lands.
“Rats are sneaky and hard to spot,” Long said. “If you see damage, including digging in the soil but no wildlife, suspect rats.”
For more information on controlling roof rats, download Quinn and Baldwin's free UC ANR publication 8513, Managing Roof Rats and Deer Mice in Nut and Fruit Orchards at http://anrcatalog.ucanr.edu/Details.aspx?itemNo=8513.
For more information about ground squirrels, download the free UC IPM Best Management Guidelines http://www.groundsquirrelbmp.com or UC IPM Pest Note http://ipm.ucanr.edu/PMG/PESTNOTES/pn7438.html.
And there's more on rats in the orchard:
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=26570
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=24581
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=19525
- Author: Ben Faber
Earthworms are commonly associated with “healthy” soils and in many cases they are good indicators. See a previous blog: http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=23945
In a recent blog, Michigan State University is telling a different story: http://msue.anr.msu.edu/news/the_dirt_about_earthworms
The popular view of earthworms – beneficial creatures that aerate the soil, feed robins and make good fishing bait – may be true in our gardens and tilled farm fields, but in forests it is a different matter.
Earthworms are not native to Michigan and the Great Lakes region, at least not since before glaciers covered the region; they were brought here during European settlement in the 1800s or possibly earlier. Plants, wildlife and forests evolved without any of these creatures around. They are now an invasive species that harms forests.
In gardens and agricultural fields, earthworms help improved soil structure and fertility, but in forests their effects are much different. Hardwood forests without earthworms have a thick layer of slowly decomposing leaves, or “duff” that promotes a rich community of wildflowers, tree seedlings and small animals. Earthworms change that environment dramatically by essentially consuming the duff, thereby destroying habitat and reducing fertility. In contrast to their effect in gardens, earthworms cause forest soils to become more compacted. As a result of habitat loss, fertility declines and soil compaction, these forests may be less productive and have poorer new tree regeneration in the long run.
If that wasn't bad enough, research shows that the combination of excessive browsing by deer (another serious threat to Michigan forests) and high earthworm populations in an area can have a worse effect than either one alone. Also, other invasive species, such as buckthorn, may have an easier time getting established in earthworm-infested areas. Without a diverse forest floor and new seedlings, the long term health of woodlands is threatened.
The connection between climate change and earthworms is complex. A warmer climate and longer growing season may hasten earthworm migration to previously worm-free forests. Introduction of earthworms make them more vulnerable to other climate-related stresses, such as more frequent and longer droughts. Although earthworms may reduce the amount of carbon entering the atmosphere through their soil action, on balance these creatures are a bad deal for northern forests.
Earthworm populations are not the same throughout Michigan forests – some areas have dense populations, others have few or none. They get from place to place very slowly. People, however, can transport them much more quickly on muddy tires, soil moved from place to place, and discarded fishing bait. There is no way to eliminate earthworms once they become established in woodlands.
In California, we have some native species of earthworms, but in many cases, non-native introduced species have come to dominate. The predominant native species belong to the Argilophilus and Diplocardia while many of the non-native are of European in origin in the Lumbricidae family. Many of these non-natives were probably introduced by settlers bringing plants from home, which had soil containing the worms. A survey of California earthworms by the US Forest Service can be found at:
https://www.fs.fed.us/psw/publications/documents/psw_gtr142/psw_gtr142.pdf
This is a wonderful description of earthworm biology and their occurrence in the California landscape.
- Author: Ben Faber
So, I got the question of what a carton of ‘Meyer' lemons weighs
Because different types of fruit are different sized, but usually the container in which it is sold stays the same, the product is going to have a different weight for the same volume. Big fruited pummelos fit fewer fruit and weigh less in a given volume than little kumquats will. However, some varieties are also sold by the weight. California ‘Valencia' oranges for some reason used to weigh 37.5 pounds per carton until 2010 when it was restandardized to 40 pounds. That kind of makes sense.
A local tangerine packer/grower says that they have always packed into half-bushel “cartons” which are 38-pound cartons. More and more the “Cuties” and “Halos” go into 5-pound equivalent cartons.
A California carton is different from a Florida carton which is 4/5 of a bushel box or a ½ field box. There a field box is 1 3/5 bushel or a 2-compartment open-top wooden container equivalent to 90 pounds of oranges or 85 pounds grapefruit or 95 pounds tangerines.
From Google:
A bushel (abbreviation: bsh. or bu.) is an imperial and US customary unit of weight based upon an earlier measure of dry capacity. The old bushel was equal to 2 kennings , 4 pecks or 8 gallons.
The name comes from the Old French boissiel and buissiel, meaning "little box". It may further derive from Old French boise, meaning "little butt".[
The butt was a measure of liquid volume equaling two hogsheads. This equated to 108 imperial gallons (490 l) for ale or 126 imperial gallons (570 l) for wine (also known as a pipe), although the Oxford English Dictionary notes that "these standards were not always precisely adhered to".[1][2]
The butt is one in a series of English wine cask units, being half of a tun.
The tun (Old English: tunne, Latin: tunellus, Middle Latin: tunna) is an English unit of liquid volume (not weight), used for measuring wine,[1] oil or honey. Typically, a large vat or vessel, most often holding 252 wine gallons, but occasionally other sizes (e.g. 256, 240 and 208 gallons), was also used.
So that's what a carton of ‘Meyer' lemons weighs.
Avocados are usually packed into lugs which weigh 25 pounds and can hold a variety of different sized fruit, but they all fit into the same sized carton.