There is culture in agriculture. Mary Lu Arpaia says she spent hours looking at the avocado pictures, along with those of other fruit crops.
The USDA Pomological Watercolor Collection is one of the most unique collections in the Rare and Special Collections of the National Agricultural Library (NAL). As a historic botanical resource, it documents new fruit and nut varieties, and specimens introduced by USDA plant explorers from the late 19th and early 20th centuries.
The collection spans the years 1886 to 1942. The majority of the paintings were created between 1894 and 1916. The plant specimens represented by these artworks originated in 29 countries and 51 states and territories in the U.S. There are 7,497 watercolor paintings, 87 line drawings, and 79 wax models created by approximately 21 artists.
Lithographs of the watercolor paintings were created to illustrate USDA bulletins, yearbooks, and other publications distributed to growers and gardeners across America.
Today, the collection is preserved in NAL's Rare and Special Collections, where it serves as an important research tool for a variety of users, including horticulturists, historians, artists, and publishers. In 2010 and 2011, the entire printed collection was digitized to improve public access to this valuable resource, and to better preserve the paintings by reducing the need for researchers to handle them. Today, the whole collections is searchable.
In 1886, the United States Department of Agriculture (USDA) established the Division of Pomology to oversee the collection and distribution of new varieties of fruits, and to disseminate information to fruit growers and breeders. USDA commissioned artists to create technically accurate illustrations of newly introduced cultivars for the division's publications. In 1887, William H. Prestele was appointed as the first artist for the Division of Pomology. Henry E. Van Deman, division chief, explained the importance of Prestele's appointment in his 1887 Report of the Pomologist:
Over the years, other artists were also assigned to the division and their watercolors were used for lithographic reproductions in USDA publications and as scientific documentation of research results. Although some of the watercolor paintings are not signed, we know of 21 artists (nine of whom were women) who contributed to this important resource.
Lamb's Lemon. Whatever happened to it?
Why are avocado roots coarse, but dense, while grass roots are a fine mat?
It has long been one of the best kept secrets in the underground world: what determines the variation in form and function of plant roots? An international team of researchers, led by scientists from Wageningen University & Research and the German Centre for Integrative Biodiversity Research in Halle-Jena-Leipzig, has revealed the strategies that roots use to invest in their tissues: do-it-yourself or outsourcing. In Science Advances they present a new framework that allows us to understand the variation in form and function in roots. “It felt like discovering a hidden treasure”.
Plants, like many other organisms, follow rules of economics when investing in their tissue. The currency is not money, but carbon and nutrients. This economics gradient flows from ‘live fast, die young' such as the Lathyrus or ginkgo, to ‘slow and steady' as the oak does. This economic theory works well for leaves. It was long assumed that the same principle applied to the roots, but researchers' efforts to deliver proof, failed repeatedly.
Each of us had a piece of the puzzle, but no-one had the whole picture. There it is: You can do it alone, or work together. Plants are just like humans. Liesje Mommer
A new collaboration gradient: an onion outsources
This problem has now been solved using a database of root characteristics of 1781 plant species from around the globe. In addition to the classical ‘fast-slow' gradient, there is a second, independent axis that is essential in understanding the form and function of plant roots. This axis is the ‘operational' gradient for nutrient uptake. It goes from a do-it-yourself strategy with many thin roots, such as followed by the cuckoo flower, to a policy of outsourcing, such as the onion. The onion collaborates intensively with soil fungi, forming a partnership of roots and fungi (mycorrhiza). “Roots that work together with fungi must make room for an 'exchange counter' - sugars go from the plant to the fungi and nutrients go the other way around. That "counter" takes up space in the outer cells of the root, which are therefore thicker than in "do-it-yourselfers", says Prof. Liesje Mommer of Wageningen University & Research. “This new operational axis shows how roots have different ways of functioning.”
Figure: Plant root strategies. Plant roots worldwide vary in their strategy for obtaining nutrients. Do-it-yourselfers have all their equipment on baord. Outsourcers form alliances with soil fungi in exchange for sugars.
This new framework for understanding variations in root characteristics offers recommendations to better understand the way roots work. This insight is useful in future research to predict the subterranean plant response to changing environmental conditions, or to launch new breeding programmes.
Professor Liesje Mommer on how the project was started: “It was a collaboration between renowned researchrs from Europe and the United States, during an inspiring workshop in Leipzig. We knew a treasure was buried underground near the plant roots, and that finding it required collaboration. Each of us had a piece of the puzzle, but no-one had the whole picture. There it is: You can do it alone, or work together. Plants are just like humans.”
The rains are gone and the hills are drying. The weeds in the orchards that aren't being hit by the irrigation water are drying up, as well. During winter and early spring, false chinch bug primarily feeds on foliage, stems, and seeds of wild grasses and cruciferous weeds. When vegetation dries or is cut, or weeds are treated with a herbicide, bugs move in large numbers to feed on virtually any nearby green plants, including irrigated avocados and citrus. These feeding aggregations can be very large. And the calls come in. Why they are called "false" is hard to say, because they can sure seem real.
The false chinch bug (family Lygaeidae) adult (above) is mostly light to dark gray, elongate, and about 0.12 inch (3 mm) long. Females lay eggs on host plants or in cracks in soil. The mostly pale gray nymphs
have inconspicuous reddish to brown abdominal markings. There are from four to seven generations per year. All stages can be present throughout the year.
False chinch bug occasionally causes severe injury on young trees by sucking sap from shoots and young stems. Infested shoots wither and die suddenly after attack, which typically occurs in May and June. Economic damage normally occurs in groves away from the coast only on young trees in border rows adjacent to uncultivated areas or grasslands. Otherwise healthy mature trees tolerate bug feeding.
So what to do? Monitor during late winter and early spring if young avocado/citrus trees are growing inland near unmanaged areas most susceptible to false chinch bug migrations. Before winter weeds dry or are cut, look for bugs on fences and weedy areas adjacent to young trees.
If false chinch bugs are common, consider treating weedy borders to kill bugs before they migrate. Only border trees may need treatment.
There are other insects that can cause these feeding symptoms, such as stinkbugs, and leaf blight can look very similar to the feeding damage that these insects do. So make sure, it is false chinch bug that is causing the problem and not an irrigation issue.
See IPM Guidelines: https://www2.ipm.ucanr.edu/agriculture/avocado/False-chinch-bug/
This is a lousy close up of a nymph
Good photos of adults by Surendra Dara
The tree damage images below were provided by Tom Roberts, Integrated Consulting Entomology
Argentine Ant Management in Citrus (July 8, 2020)
What Are the UC Ag Experts Talking About?
What is involved in the webinars?
A series of 1-hour webinars, designed for growers and pest management professionals, highlighting various pest management and horticultural topics for citrus, avocados, and other subtropical crops. Master Gardeners can benefit from participating, but the pest management methods presented, especially the pesticides, are not to be followed without a clear understanding of their legal use by homeowners.During each session, a UC Expert on the subject makes a presentation and entertains write-in questions via chat during and/or after the presentation. As we develop this program, we may expand to other crops. Both DPR CE units are available, as are CDFA-CCA units