Topics in Subtropics Blog
2018 Pitahaya/Dragon Fruit Production Seminar
San Diego County Farm Bureau
420 South Broadway, Suite 200 | Escondido, CA 92025
Friday - August 24, 2018
7:00am – 4:30pm
TOPICS TO BE COVERED:
- San Diego County Agriculture – Water, Policies and Regulatory Update
- Pitahaya Research Update – Variety Evaluation and Performance, Genetic Characterization
- Irrigation Water Management Strategies and Pitahaya Irrigation
- Pitahaya Post Harvest Management & Sensory Evaluation
- Pitahaya or Dragon Fruit Markets and Marketing - An Overview and Global Perspective
- Pitahaya Orchard Establishment & Economics Considerations
- Pitahaya Fertility Management & Soil Analytical Reports (Tentative)
- Nematode Issues and their Impact for Pitahaya Production
- Insect Pest Management & Pesticide Use Safety for Pitahayas and Other Specialty Crops
- Weeds and Weed Management Strategies for Specialty Crops, including Pitahaya
- Diseases – Diagnosis and Management Strategies for Pitahaya Production
- Hydroponics – An Evaluation of Soilless Substrates for Pitahaya Production (Tentative)
2018 Pitahaya/Dragon Fruit Festival/Field Day
UC South Coast Research and Extension Center
7601 Irvine Boulevard | Irvine, CA 92618
Saturday - August 25, 2016
6:30am – 3:30pm
TOPICS TO BE COVERED:
- Review of Pitahaya Varieties and Hand Pollination Demonstration
- Integrated Pest Management Strategies for Specialty Crops Production
- Pitahaya Irrigation Research and System Design Consideration
- Pitahaya Trellis Systems Demonstration
- Pitahaya Production for Home or Backyard Growers
- Pitahaya or Dragon Fruit and Ice Cream Tasting
REGISTER EARLY. This event has sold out in the past!! Attendance is limited to 60 participants for the seminar on August 24th and 100 for the festival/field day on August 25th. This would also help us plan for handouts and cuttings. No refunds will be issued, but substitutions are allowed.
PRICINGincludes continental breakfast, refreshments, lunch, (Catered by Phil's BBQ on 8/24), pitahaya/dragon fruit ice cream, smoothie tasting, and an information packet:
- Package Registration for Seminar & Festival/Field Day: $80.00,
If paid online with a credit card or post-marked by Friday - August 17, 2018.
No package registrations after this date.
- Seminar Registration ONLY: $60.00,
If paid online with a credit card or post-marked by Friday - August 17, 2018
$70.00 after this date or at the door, if space allows*
- Festival/Field Day Registration ONLY: $ 40.00,
If paid online with a credit card or post-marked by Friday - August 17, 2018
$50.00 after this date or at the door, if space allows*
*Walk-ins will be allowed if space is available, but you MUST have exact change or checks. Credit cards will NOT be accepted day of.
Please be aware that you WILL be turned away if space is not available! NO EXCEPTIONS.
TO REGISTER,please complete the online registration form at:
For registration questions, please contact
Administrative Assistant II
The following article is from the UC ANR Integrated Pest Management website, authored by Cheryl Wilen.
Puncturevine (Tribulus terrestris) is an aptly named summer annual found widely in California. Native to southern Europe, it can grow under a wide range of conditions, but its success is likely due to its ability to thrive in hot and dry conditions where other plants cannot. It can be a major problem in orchards, pastures, turf, and along roadsides and ditch banks. Although it is known to be toxic to sheep, its main weedy characteristic, as indicated by its common names of puncturevine or caltrop, is its spiky seedpods. (A caltrop is a metal device, used to deter passage by vehicles with pneumatic tires or the hooves of horses; it has four projecting spikes so arranged that when three of the spikes are on the ground, the fourth points upward to poke a tire or hoof.) The seeds of puncturevine are enclosed in a hard caltrop-like case that can injure livestock, people, and pets when stepped on and can even puncture bicycle tires. Another common name is "goathead." Growing up in Fresno it was always a problem with bike tires. It seemed that more time was spent tire repairing than riding the bike.
It's distribution is pretty much throughout California and seems more concentrated in Southern California. There have been more calls recently about the plant, but it has been a common complaint for many years.
IDENTIFICATION AND LIFE CYCLE
Puncturevine is a summer annual broadleaf weed that generally grows low to the ground forming dense mats 2 to 5 feet in diameter. The stems radiate out from a central point at the taproot. The plant does not root from the stems. The hairy leaves are opposite each other and divided into four to eight pairs of leaflets that are also opposite each other. Yellow flowers up to 1/2 inch wide with five petals are found in the leaf axils. After the flower is pollinated, a seedpod forms that is a cluster of five flat spiny burrs containing up to five seeds. As the seedpod matures, it turns gray or tan, gets very hard and breaks apart so that the individual spikes, or burrs, can stick into passing animals and tires. These burrs disperse by adhering to tires, shoes and clothing of people, and the fur, feathers, or feet of animals.
Puncturevine germinates in the spring and summer from seeds produced the previous year. Good soil moisture and warm temperatures are needed for germination, but after the plant is established it can tolerate dry soils due to its rapidly produced deep taproot. The plant may start flowering within 3 weeks of germination and flowering will continue throughout the summer. Seeds are primarily dormant in the first season, but may germinate the next spring. Seeds may remain viable in the soil for up to five years. Puncturevine plants cannot tolerate freezing temperatures.
A typical puncturevine plant will produce 200 to 5,000 seeds during one growing season, depending on available soil moisture and other environmental factors. These seeds and those that did not germinate from previous seasons will contribute to the potential weed population the following year.
With its deep taproot, puncturevine competes aggressively for water and nutrients in tree and field crops and turf. Puncturevine in hay will markedly reduce the quality of the product.
When allowed to grow unchecked, puncturevine will develop into a thick mat, hiding the sharp burrs. Even under limited growth conditions, puncturevine's prolific production of the seed burrs creates dangerous conditions for livestock, people, and pets.
Grazing livestock in areas infested with puncturevine is not recommended. The sharp spines of the seed burr can injure the mouth and digestive tract or feet of animals. Puncturevine can be particularly toxic to sheep, causing sensitivity to light resulting in skin lesions and swelling of ears and lips. Severe effects include blindness, necrosis of skin, loss of lips and ears, and death in young animals. Additionally, puncturevine may contribute to nitrate poisoning in sheep and cattle. Symptoms of nitrate poisoning include labored breathing, staggering, tongue and the white of the eyes turning blue, and loss of appetite.
Long-term control of puncturevine can be achieved by reducing the amount of seeds in the soil. This is best accomplished by removing plants before they produce seeds (i.e., before or at flowering) and continuing to do so over several years. Burrs that have dropped after removing the plant may be collected and removed by sweeping or raking the ground. Even patting the ground with a piece of carpet will help collect the burrs. Biological control from two introduced weevils is also very effective, but there may be resurgences every few years as the number of the weevils decline along with the population of the puncturevine.
The primary method of management for puncturevine in the home landscape and garden is removal of seedlings and older plants by hand or hoeing, taking care to also remove any burrs that fall off the plant. Avoid bringing puncturevine into uninfested areas on shoes and the wheels of mowers or carts.
Cultural and Mechanical Control
In most situations, puncturevine is best controlled by hand removal or by hoeing to cut the plant off at its taproot. Monitoring the area and removing the weed throughout the late spring and into the summer will greatly reduce the impact of the weed the next year. Shallow tilling (about 1 inch deep) of seedlings or small plants can be effective in larger areas. Deeper tilling is not recommended since this may bury seeds and they may be able to germinate for several years afterwards. Hand removal, hoeing, or cultivation should be initiated prior to flowering and seed production. Mowing is not an effective method of control since the plant grows low to the ground.
Mulches can be used to control common puncturevine in ornamental plantings, orchards, vineyards, vegetable crops, and gardens, if they screen out all light. To be effective, organic mulches should be at least 3 inches thick. However, puncturevine burrs that fall onto mulch surfaces can establish on the mulch surface due to the puncturevine's deep taproot. Synthetic mulches, which screen out light and provide a physical barrier to seedling development, also work well.
Aeration of compacted sites and planting competitive desirable plants can also reduce the impact of puncturevine by making the area more favorable for the growth of the desired plants and reducing resources available to the weed.
Two weevils, Microlarinus lareynii and M. lypriformis, native to India, France, and Italy, were introduced into the United States as biocontrol agents in 1961. Microlarinus lareynii is a seed weevil that deposits its eggs in the immature burr or flower bud and the larvae feed on and destroy the seeds before they pupate and emerge as adults, disperse, and start the cycle over again. Generation time is 19 to 24 days in the summer in southern California. Microlarinus lypriformis is a stem weevil that has a similar life cycle except that it lays its eggs in the undersides of stems, branches, and the root crown. The larvae tunnel in the pith where they feed and pupate. The adults emerge from holes chewed in the upper surfaces of the stems, branches, and crowns. Adults of both species overwinter in plant debris. Although the stem weevil is slightly more effective than the seed weevil when each is used alone, the weevils are most effective if used together and the puncturevine is moisture-stressed.
Both species of weevils are available for purchase from biological control suppliers but purchase and release is not generally recommended because weevils collected from other areas may not survive at your location. In most California counties where releases would be beneficial, county agricultural commissioners have release programs or can direct you to collection sites where you may be able to collect them yourself. Contact your county agricultural commissioner's office for more information.
Emergence hole of the seed weevil, Microlarinus lareynii, in a puncturevine seed capsule.
Chemical control is generally not necessary for the control of puncturevine in the home landscape. However, in large areas, or places where there was a heavy infestation in previous years so that it's difficult to remove by hand, hoeing, or tilling, herbicides may be used to control puncturevine.
There are few preemergent herbicides that are effective. Products containing oryzalin, benefin, or trifluralin will provide partial control of germinating seeds. These must be applied prior to germination (late winter to midspring).
After plants have emerged from the soil (postemergent), products containing 2,4-D, glyphosate, and dicamba are effective on puncturevine. The smaller or younger the plant, the better the postemergent herbicides work. Dicamba and 2,4-D will injure most broadleaf plants so it is important that they only be applied to the weeds and drift is minimized. They can be applied to lawns without injuring the desired grass. Glyphosate will kill or injure most plants so it should only be used as spot treatments or on solid stands of the weed.
Mouse collection of tasty puncturevine seeds. Thanks to KenGerry
Antarctic fungi found to be effective against citrus canker
Brazilian researchers have identified activity against Xanthomonas citri in 29 fungi isolated from samples collected in Antarctica; one of the compounds inhibited reproduction of the bacterium by up to 98 percent
A research team at the São Paulo State University's Bioscience Institute (IB-UNESP) in Rio Claro, Brazil, has identified 29 fungi with proven action against Xanthomonas citri, a bacterium responsible for citrus canker, an endemic disease in all citrus-producing countries. The origin of the fungi is surprising. They were isolated from samples of soil and marine sediment collected in Antarctica.
"These fungi live in isolated conditions and proliferate under inhospitable conditions including low temperatures and high levels of ultraviolet radiation," says Daiane Cristina Sass, a Professor at UNESP who heads a project engaged in a search for microorganisms that produce compounds with antibacterial action for use in agriculture, with support from the São Paulo Research Foundation - FAPESP.
"How have they adapted to survive in an environment so hostile to life? We wanted to see if they produced molecules with unique structures that protected them from infections and might therefore be capable of antibacterial action." Sass wrote an article published in Letters in Applied Microbiology - jointly with IB-UNESP colleagues Lara Durães Sette and Henrique Ferreira, among others - which shows some of the research's results.
More efficiency on fighting citrus canker
Although the bacterium can be combated in several ways, none is sufficient to eradicate the disease. Therefore, new chemical or biological methods of protecting citrus groves have to be pursued.
The disease is controlled directly by growers. The recommended measures include spraying trees with copper-based products and replacing infected trees with healthy new plantings derived from more resistant varieties. Control of the citrus leaf miner (Phyllocnistis citrella) is also advisable. The wounds made by larvae of this moth in feeding on the plant exacerbate citrus canker by serving as an entry point for X. citri.
"The main method for combating citrus canker consists of spraying trees with copper compounds. The downside is that when even small amounts are used for a long period, copper accumulates in the fruit, soil and water, eventually contaminating the entire environment. For this reason, we're looking for new compounds that are less aggressive to the environment and also less harmful to humans," Sass explained.
Collection and isolation of the Antarctic fungi
On the extent of the Sass-headed project and its research on biotechnology, the team came up with the idea of investigating the collection of fungi curated by Professor Sette, which resulted from Antarctic summer expeditions to the South Shetland Islands in 2013 and 2015 as part of Project Microsfera, conducted under the aegis of the Brazilian Antarctic Program (PROANTAR) and sponsored by the National Council for Scientific & Technological Development (CNPq).
Sette leads the project "Marine and Antarctic mycology: diversity and environmental application", also supported by FAPESP.
Sette isolated 33 filamentous fungi from samples collected in soil under rotten wood on Deception Island and 53 filamentous fungi from marine sediments at a depth of 20 meters in Admiralty Bay, King George Island. All fungal strains are kept at UNESP's Microbial Resource Center (CRM).
The FAPESP-funded research found that 29 of the 86 Antarctic fungi they isolated (19 of marine origin and ten terrestrial) contained compounds with proven action against X. citri.
Isolating the compounds produced by the fungi and verifying their antibacterial activity involved several stages. The process began with isolation of the fungi, which were then grown for several days in culture dishes with nutrients.
The fungi were cultured in liquid medium and shaken for 20 days at 15 °C. The solid biomass was separated from the liquid portion, and both parts were submitted to processing with solvents to obtain intracellular and extracellular extracts.
The researchers obtained 158 extracts. Each extract was diluted at several concentrations (2.10 mg/ml-0.02 mg/ml) and tested against X. citri. In the case of the soil fungi, most of the extracts with antibacterial action were intracellular in origin, while for the marine fungi, only the extracellular extracts hindered the bacterium's growth.
"We wanted to determine the lowest concentration of each extract that inhibited growth in 90% of cases," Sass said.
Some (12) of the extracts affected bacterial growth at lower concentrations than the highest tested, and ten of these inhibited growth in more than 90% of cases at concentrations of 1.5 mg/ml-1.0 mg/ml.
"At maximum concentration, one extract inhibited growth by up to 98%, and another inhibited it by about 80% at 0.52 mg/ml," Sass said. "It's important to note that we're talking about extracts [which contain varying amounts of molecules]. If an extract contains only one compound that's responsible for this bioactivity, the compound may display good antibacterial activity at much lower concentrations."
Twenty of the isolated fungi with action against X. citri belonged to the genus Pseudogymnoascus and were extracted from terrestrial and marine samples. Next came Penicillium (five), followed by Cadophora (two), Paraconiothyrium (one) and Toxicocladosporium (one), all extracted from marine sediments.
Having identified the extracts with action against X. citri, the researchers are now working to find out which chemical compounds give them this antibacterial capability.
"We expect to identify and purify some of these bioactive compounds, as well as to complete toxicology testing on them, within 18 months or less," Sass said.
The researchers plan to patent the compounds they identify. They also hope to persuade pesticide manufacturers to develop commercial products for combating citrus canker based on these compounds.
Twenty of the isolated fungi with action against X. citri belonged to the genus Pseudogymnoascus and were extracted from terrestrial and marine samples. Next came Penicillium (five), followed by Cadophora (two), Paraconiothyrium (one) and Toxicocladosporium (one), all extracted from marine sediments./h1>
A recent request from the San Diego area has prompted the reposting of this blog by Guy Kyser, UC Davis Plant Sciences Specialist
A neighbor asked me to identify a robust perennial that keeps coming up in his garden. It had long, tropical-looking leaves and floppy racemes with small white flowers. This was a new one for me. Turned out it was common pokeweed (Phytolacca americana), a native of eastern North America. In the south some people eat it (poke salad), and a few southerners probably brought it west as a garden vegetable. But the whole plant is toxic if improperly prepared, so it's the fugu of weeds.
A couple of weeks later my daughter brought home a stalk of purple berries and asked if she could eat them. “No,” I said, “they contain numerous saponins and oxalates.” I began to wonder if there's more pokeweed around than I realized.
Then Gillies Robertson of Yolo RCD sent photos of a purple-berried plant found along a slough near Grimes. Common pokeweed again.
Pokeweed is in the Phytolaccaceae. This weed can grow to 10 feet tall. It dies back in winter then reemerges from the ground in spring, growing from a fat fleshy storage root. The leaves are large, 3 inches to a foot long and 1 to 5 inches wide, often with reddish stalks and lower veins. From August to October, pokeweed produces racemes of white flowers followed by reddish-purple berries. In its natural state, all parts of the plant, especially the root, are toxic to humans. Birds can eat the berries but sometimes act funny afterwards.
This plant can be found in most of the contiguous states. In drier regions, it prefers gardens and irrigated areas. Southerners with pokeweed experience suggest controlling it by digging up as much of the taproot as possible and/or by cutting off the stalks and painting the stubs with concentrated glyphosate (e.g. Roundup). Either way, treatments will probably have to be repeated until the plant's storage reserves are worn down. And it's a good idea to deal with pokeweed before it produces berries and seeds.
Since this is the first year I've seen it, and since I suddenly ran into it in three locations within a few weeks, I'm guessing that the common pokeweed population is expanding. This plant seems robust enough to cause some trouble if it becomes established in natural riparian areas.
It's been quiet for awhile, just odd winter weather and fire and ash and hot hot heat andsuddenly we see a beautiful insect we haven't seen in a while. Jarrell Larmon is a PCA who was nosing around in a Satsuma orchard and he turned up a Barnacle Scale, the likes we havent seen in about 4 years. Pretty little thing. Last time it came under pretty good biological control in no time.
This is the image from USDA
a PCA here in Ventura, recently found an unusual scale in lemon here. It is barnacle scale with a typically long Latin name - Ceroplastes cirripediformis. It is unlikely to be any worse than other scales, but it's something to keep our eyes on. This is one of the soft scales, often called wax scales because of the wax they produce. It turns out that this has been described as being in Southern California for years, but some years they are just more present. For more on "Wax" scales see the University of Florida site:
or our UC IPM website
And this is the scale that Jane found.