- (Focus Area) Agriculture
- Author: Ben A Faber
- Posted by: Gale Perez
Rely® 280 Herbicide Available for Use in California Avocado Groves
The California Department of Pesticide Regulation (DPR) has approved the herbicide Rely® 280 (glufosinate-ammonium) for use in avocado groves in California. Rely® 280 is a post-emergence broad-spectrum herbicide for use against broadleaf and grassy weeds. Glufosinate-ammonium is an excellent alternative to glyphosate, especially for those weeds that have developed glyphosate resistance.
The California Avocado Commission provided funding for Dr. Peggy Mauk, extension professor for subtropical horticulture at the University of California, Riverside, to conduct efficacy trials with glufosinate-ammonium and the IR-4 program provided funding for the required phytotoxicity (crop safety) trials. “Glufosinate-ammonium is an effective broad-spectrum herbicide,” said Mauk. “The weed that is the biggest problem here in Riverside is mare's tail or hairy fleabane (Erigeron bonariensis). Glufosinate will kill it depending on the application timing and size of the plants. Treating for weeds is also going to be seasonal… the spring is usually worse because spring rains bring a lot of weeds, especially this past year.”
Dr. Mauk's phytotoxicity trials found minimal damage, assuming sound application practices are followed. “Spray applications should not be made when there is a breeze,” Mauk emphasized. “If the wind carries the herbicide onto the plants, there can be some leaf discoloration. The discoloration appears as occasional purple spots on the leaves. There is not widespread damage. We also never saw any discoloration on the avocado fruit.”
General questions about this registration can be directed to CAC's Research Director Dr. Tim Spann at tim@spannag.com or (423) 609-3451. For specific questions regarding the use of Rely® 280, growers should contact their Pest Control Advisor.
Original source: Topics in Subtropics blog | May 31, 2024
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- Author: Ben A Faber
Florida's citrus industry has long been susceptible to freezes, hurricanes, and disease. A series of devastating freezes in the 1970s and 1980s caused production to shift to more southern regions of the State. Then after near-record output in the 2003/04 season, subsequent events decreased Florida's orange output at an average rate of 6 percent a year. Between 2004 and 2005, 4 hurricanes reduced the size of the orange crop and further spread citrus canker, a bacterial disease damaging to tree health and fruit quality, to previously unaffected areas. The Florida citrus industry faced an additional challenge in 2005, when citrus greening disease, a bacterial disease deadly to citrus trees, was first detected in its commercial groves. Citrus greening disease leads to premature fruit drop, unripe fruit, and eventual tree death. With no known cure, citrus growers use a variety of management strategies to protect young trees, increase tree immune response, sustain grove health, and improve fruit marketability. While these management strategies can partially offset yield losses, they increase the costs of production. Hurricanes in 2017 and 2022 dealt further damage to Florida's citrus industry. Since 2003/04, bearing acreage of Florida's orange trees has declined at an average rate of 3 percent per year. In April 2024, USDA forecast Florida's orange 2023/24 production at 846,000 tons, 19 percent higher than the previous year but the second-lowest harvest in nearly 90 years. This chart updates information in the USDA, Economic Research Service Fruit and Tree Nuts Outlook, published in March 2023.
From USDA: https://www.ers.usda.gov/data-products/chart-gallery/gallery/chart-detail/?chartId=109051
- Author: Kathy Keatley Garvey
Oh, there ain't no bugs on me
There ain't no bugs on me
There may be bugs on some of you mugs
But there ain't no bugs on me
You can hear it on YouTube.
UC Davis distinguished professor James R. Carey of the Department of Entomology and Nematology, drew national news media coverage in 1991 when he declared that the medflies are "established" here, that the "recurring outbreaks" are not caused by tourists continually bringing infested fruit to California in their airline baggage.
Today Carey says that California's fruit fly invasion is in "crisis mode."
The professor will present a Department of Entomology and Nematology seminar on "California's Fruit Fly Invasion Crisis" at 4:10 p.m., Monday, June 3 in Room 122 of Briggs Hall. It also will be on Zoom. The Zoom link:
https://ucdavis.zoom.us/j/9 5882849672.
"After seven decades of near-continuous outbreaks in scores of California cities, tephritid fruit fly invasions (e.g., Mediterranean, oriental, peach, and Mexican fruit flies) are reaching critical mass, with many of the annual eradication programs morphing into below-the-radar, never-ending fruit fly control programs," Carey says in his abstract. "Permanent establishment of any one of these tropical species has the potential to shut down the multi-billion dollar domestic and foreign markets for hundreds of California fruit and vegetable crops."
"I will present an overview of the long-developing crisis, discuss lessons learned from analysis of fruit fly detection databases, and argue that, in order to have any chance at stemming this ever-rising tide, CDFA and the USDA urgently needs to switch from their historic, ad hoc eradication strategy to a new one that is evidence-based and far more scientific."
Carey served on the CDFA's Medfly Scientific Advisory Panel from 1987-1994, testified to the California Legislature "Committee of the Whole" in 1990 on the Medfly Crisis in California, and authored the paper "Establishment of the Mediterranean Fruit Fly in California" (1991, Science 258, 457).
Carey is a fellow of four professional societies: the Entomological Society of America, the American Association for the Advancement of Science, the California Academy of Sciences, and the Gerontological Society of America. He is former director (2003-13) of a 11-university consortium funded by the National Institute on Aging (NIH/P01) on the evolutionary ecology of lifespan.
- Author: Luis Espino
I received several calls and comments about issues with tadpole shrimp this spring. While this pest is well known to growers and PCAs, it can still be difficult to manage during planting time. Mistiming of insecticide application can result in shrimp damage. Tadpole shrimp develop fast, and really fast when it is warm. This spring was warmer than last year during mid to late May, when most of the rice was being flooded and planted. If a field takes long to flood and seed, the shrimp have more time to develop and may injure seedlings as soon as they start germinating in the field. What shrimp size can injure rice? If you can see the shrimp, they can injure rice. However, larger shrimp will cause more injury than smaller shrimp. The figure below shows how, in a field infested with TPS, the stand is reduced more the later the field is seeded after flood (DAF).
Some of the fields where shrimp injury occurred this year are fields where pyrethriods do not control shrimp anymore. In these fields, Dimilin is working well. However, remember that Dimilin may take a few days longer to clear up the shrimp than pyrethroids and copper, especially when the shrimp are large.
When shrimp injury occurs soon after seeding, they will feed on the emerging coleoptile and radicle, completely consuming these tissues. When this happens, seeds won't recover. If only some of the tissue is consumed, seedlings may be able to continue growing once the shrimp is controlled. The picture below shows seedlings where the coleoptile and radicle have been consumed compared to two uninjured seedlings at the bottom of the picture.
If a field is damaged by tadpole shrimp, reseeding is an option. Some trials conducted a couple of years ago by Bruce Linquist showed that the optimum stand is about 25 plants/ft2. Rice plants can compensate when the stand is reduced. For example, when the stand is reduced to 12.5 plants/ft2 (half the optimum), yield is reduced only 10%. In general, reseeding should be considered when the stand is reduced to 10 plants/ft2 or less. Draining the field before reseeding increases the likelihood of establishment of the reseed, but it may not be possible in all cases. When reseeding, use a higher seeding rate to increase the chances of establishment and make sure the shrimp have been controlled. As a grower told me a few years ago, remember that reseeding is a bit of a gamble.
- Author: Ben A Faber
Rely® 280 Herbicide Available for Use in California Avocado Groves
The California Department of Pesticide Regulation has approved the herbicide Rely® 280 (glufosinate-ammonium) for use in avocado groves in California. Rely® 280 is a post-emergence broad-spectrum herbicide for use against broadleaf and grassy weeds. Glufosinate-ammonium is an excellent alternative to glyphosate, especially for those weeds that have developed glyphosate resistance.
The California Avocado Commission provided funding for Dr. Peggy Mauk, extension professor for subtropical horticulture at the University of California-Riverside, to conduct efficacy trials with glufosinate-ammonium and the IR-4 program provided funding for the required phytotoxicity (crop safety) trials. “Glufosinate-ammonium is an effective broad-spectrum herbicide,” said Mauk. “The weed that is the biggest problem here in Riverside is mare's tail or hairy fleabane ( Erigeron bonariensis). Glufosinate will kill it depending on the application timing and size of the plants. Treating for weeds is also going to be seasonal…the spring is usually worse because spring rains bring a lot of weeds, especially this past year.”
Currently, growers must have a copy of the DPR approved supplemental label in their possession when using Rely® 280. The DPR-approved label has a stamp on it with the wording "LABELING ACCEPTABLE State of California Department of Pesticide Regulation Pesticide Registration" and can be downloaded here. This supplemental label expires on December 1, 2025, and BASF, Rely® 280's manufacturer, anticipates that all old product will be used by that date and new product with avocado listed on the package label will be fully in the supply chain by that date.
Dr. Mauk's phytotoxicity trials found minimal damage, assuming sound application practices are followed. “Spray applications should not be made when there is a breeze,” Mauk emphasized. “If the wind carries the herbicide onto the plants, there can be some leaf discoloration. The discoloration appears as occasional purple spots on the leaves. There is not widespread damage. We also never saw any discoloration on the avocado fruit.”
General questions about this registration can be directed to CAC's Research Director Dr. Tim Spann at tim@spannag.com or 423-609-3451. For specific questions regarding the use of Rely® 280 growers should contact their Pest Control Advisor.