Posts Tagged: agriculture
Watch Out for Fruit Flies
California inundated with invasive fruit flies
Bodil Cass
Extension Subtropics Entomologist, Dept of Entomology, UCR
California is experiencing an unusually high number of invasive fruit fly infestations. There are seven active regional quarantines in different areas of the state for four different species of exotic fruit flies in the family Tephritidae: Medfly (Ceratitis capitata) and Tau fly (Zeugodacus tau) in Los Angeles, Queensland fruit fly (Bactrocera tryoni) at the border of Ventura/Los Angeles, and four separate quarantine areas for the Oriental fruit fly (‘OFF'; B. dorsalis) in Riverside/San Bernardino, Contra Costa, Sacramento, and Santa Clara counties. A quarantine just ended following the successful eradication of an infestation of Mexfly (Anastrepha ludens) in San Diego County.
The OFF infestation in San Bernardino/Riverside is especially serious in terms of the unprecedented number of flies found and the many acres of commercial production affected. For this species, six male flies/one mated female/one larva triggers a quarantine, but here we have detected more than 500 adult flies and are still finding more, even during winter. The affected area, including more than 550 square miles, encompasses not just residential properties but an important agricultural region with commercial farms. Farmers in the area are bringing in more trained pesticide applicators, and facing crop losses, delayed harvests, disruption to integrated pest management practices for other pests, and increased costs as they act to mitigate the damage. The unfortunate proximity of the epicenter of the outbreak to agricultural production is necessitating some problem solving and adaptation of mitigation protocols as we race to stop the fly population from establishing.
The quarantine boundary is also approaching the edge of the California Citrus State Historic Park and the University of California Riverside campus, with fly finds less than two miles from active subtropical fruit and biological control research plots, the Givaudan Citrus Variety Collection, and citrus trees of historical importance. Researchers are gauging how the infestation and mitigation protocols might impact current experiments being conducted, including delayed harvest dates, and scrambling to adapt research plans accordingly.
Usually, we have one or two small exotic fruit fly quarantines per year, so the current situation is a strain on resources statewide. The number of areas invested and the severity of the OFF infestation in San Bernardino/Riverside are stretching resources thin as the Department of Agriculture pulls insect detection specialists and staff from other projects to help place more traps, enact compliance agreements, and visit residential properties. San Bernardino County is providing yard signs to help encourage residents not to move produce while the quarantine is in effect.
Exotic fruit flies are one of the most serious threats to food production in the state, with the estimated economic cost of any one of these Tephritidae species becoming established running into the $100 of millions through crop losses, additional pesticide use, and collapse of export markets. These flies are of concern because the larvae/maggots feed on fresh fruit and vegetables prior to harvest. The immature flies chew through the fresh fruit, and it rots on the tree or vine, or drops prematurely to the ground. Fruit infested with large maggots is not marketable to consumers and not fit for human consumption. They are much more damaging than other flies, like smaller Drosophila species that develop on fruit that has already matured, been harvested and is in compost. Tephritidae flies are also highly polyphagous, with some species attacking more than 100 types of fruit, vegetables, and nuts, including the major food crops produced in the state; citrus, avocado, dates, tomatoes, bell peppers, figs, grapes, cucurbits and many specialty crops are all at risk.
We have a long-standing success record of keeping fruit flies out of the state, and fully expect to achieve eradication of all the current infestations through an approach that consists of biological control (mating disruption by sterile insect release), chemical control (targeted pesticide baits), and physical control (destruction of infested fruit from the current season and restrictions on movement of fruit from infested areas). If you have questions about a fruit fly quarantine/eradication, or if you think you have fruits and vegetables infested with fruit fly larvae, call the CDFA Exotic Pest Hotline at 1 (800) 491-1899, contact your local Agricultural Commissioner, or the University's Cooperative Extension. More information specifically for growers is available at regional Farm Bureau meetings and on the CDFA website: https://www.cdfa.ca.gov/plant/PE/InteriorExclusion/current_grower_info.html#INTRO
Image of Oriental Fruit Fly
oriental fruit fly image
Avocado Field Day
You may have missed it, or you may want to relive it. Here's a video of the June 25 Avocado Field Day at Jackson Ranch in North San Diego County:
Field Day at Jackson Avocado Ranch
avocado cluster
A Strawberry FaeireTale
The way the strawberry industry grows plants really makes them a subtropical plant. The industry is located along the coast from Monterrey to San Diego, with the bulk around Salinas, Santa Maria and Oxnard. Oleg Daugovish looks after this industry from our office in Ventura. He's written a story that illustrates the whole industry, from where the mother plants are grown near Mt Shasta to the fields along the coast. It's a story that every Caifornia kid should read about.
Mt Shasta
Estimating Avocado Water Requirement
Satellite-based irrigation tools to manage irrigation water more precisely in avocado groves
Ali Montazar, UCCE Irrigation and Water Management Advisor
in San Diego, Riverside, and Imperial Counties
The water requirement of a crop must be satisfied to achieve optimum potential yields. The crop water requirement is called crop evapotranspiration and is usually represented as ETc. By combining reference evapotranspiration (ETo) and the proper crop coefficient (Kc), crop water use (ETc) can be determined as ETc = ETo × Kc. ETo is an estimation of evapotranspiration for short grass canopy under a well-managed, non-stressed condition. ETo is the main driver to estimate or forecast crop water needs. There are user-friendly satellite-based irrigation tools available that may assist growers to schedule irrigation more effectively. These tools provide ETo forecast for up to six days in the future or/and actual ET at the scale of individual fields. This article introduces three satellite-based irrigation tools including FRET, IrriSAT, and OpenET. A comparison of the estimated daily crop water needs utilizing OpenET tool and actual ET measured for a period of 150-day is also presented for an avocado grove in the San Pasqual Valley, Escondido.
Read more about this study: https://ceventura.ucanr.edu/Com_Ag/Subtropical/?newsletteritem=100493
A screen dump of cumulative ET (inch) for the entire western states in 2021. You may zoom on the OpenET map to find your orchard for a specific time (daily, monthly, yearly) and explore the data.
OPEN ET map
Microirrigation Clogging Troubleshooting Guide
Microirrigation systems include microsprinklers for tree crops, drip emitters for trees, vines, and some row crops, and drip tape for row and field crops. Microirrigation systems apply water to the soil through emitters that are installed along drip lines and contain very small flow passages. Microirrigation systems can apply water and fertilizers more uniformly than other irrigation methods. This uniformity results in potentially higher yields, higher revenue, and reduced irrigation operating costs.
Uniformity, a performance characteristic of irrigation systems, is a measure of the evenness of the applied water throughout the irrigation system. Distribution uniformity (DU), sometimes called emission uniformity (EU), is an index that describes how evenly or uniformly water is applied throughout the field. A uniformity of 100% means the same amount of water was applied everywhere. Unfortunately, all irrigation systems apply water at a uniformity of less than 100%, and thus some parts of a field receive more water than others. Field evaluations have shown that microirrigation systems have the potential for higher uniformity than other irrigation methods. However, clogging reduces the uniformity of applied water in microirrigation systems, thus increasing the relative differences in applied water throughout a field.
The small flow passages in the emitters and microsprinklers make microirrigation systems highly susceptible to clogging. Clogging reduces the uniformity of the applied water and decreases the amount of applied water. Clogging also decreases the amount of salt leaching around the lateral line in saline soils.
The objective of this web site is to provide information to irrigators about the causes of clogging and the methods for preventing or correcting clogging problems in microirrigation systems. Among the topics covered are the sources of clogging, chlorination, preventing chemical precipitation, filtration, flushing, and monitoring microirrigation systems.
This web site is divided into sections to allow the users to more quickly access the information they want. For example, if you already know you have a clogging problem and you want to solve it, go to the section Solutions to Existing Clogging Problems - "I have a problem and I want to solve it".
https://micromaintain.ucanr.edu/
avocado irrigation 2